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International Journal of Universal Pharmacy and Bio Sciences 3(3): May-June 2014

INTERNATIONAL JOURNAL OF UNIVERSAL

PHARMACY AND BIO SCIENCES IMPACT FACTOR 1.89***

ICV 5.13*** Pharmaceutical Sciences RESEARCH ARTICLE……!!!

FORMULATION AND IN-VITRO EVALUATION OF ATOMOXETINE

HCl IMMEDIATE RELEASE TABLET

Zaz Saba Abdulraheman*, Dr. M.R. Patel, Dr. K.R.Patel

Shri B.M Shah College of Pharmaceutical Education and Research, Modasa (Arvalli):- 383315.

KEYWORDS:

Atomoxetine HCl;

Immediate release tablet;

KyronTM

T-134; KyronTM

T-314; Crospovidone.

For Correspondence:

Zaz Saba

Abdulraheman*

Address:

Shri B.M Shah College

of Pharmaceutical

Education and Research,

Modasa (Arvalli):-

383315.

Email:

[email protected]

ABSTRACT

In the present investigation was to formulate tasteless complexes of

Atomoxetine HCl with Kyron™

T-134 and to formulate tasteless

complex into immediate release tablets for the treatment of Attention-

deficit hyperactivity disorder (ADHD). Tasteless DRC were prepared

using combination of Kyron™

T-134 and drug in different ratio (1:1)

and evaluated for different factor affecting DRC on Atomoxetine HCl

loading efficiency. A 32 full factorial designs was used for optimizing

the Concentration and evaluated for various parameters and analyzed

using ANOVA and Surface Response Methodology. The study

conclusively significant taste masking of API. Maximum drug loading

was obtained at drug-resin ratio 1:1, temperature 60ºC, pH 6-7, soaking

time 30 min, stirring time 4-5 hr. The result of 32 full factorial design

showed that A5 was selected as best factorial batch, as compare to other

factorial batches. Batch A5 containing 3% of KyronTM

T-314 and 3%

of CP showed to be palatable with minimum in vitro disintegration time

(20 sec), minimum wetting time (17 sec) and percentage drug release

(99.98%) within 30 min. The studies indicate the formulation was taste

masked drug can be formulated in to immediate release tablet with view

to enhance patient compliance & to obtain faster onset of action.

According to 32

full factorial designs it was finalized that A5 proved as

an optimal batch. Batch A5 remains stable after one month accelerated

stability study. Drug and excipients are compatible to each other was

confirmed by FTIR study.

mailto:[email protected]



INTRODUCTION:

Oral routes of drug administration have wide acceptance up to 50-60% of total dosage forms. The

most popular solid dosage forms are being tablets and capsules; one important drawback of this

dosage forms for some patients, is the difficulty to swallow. Traditional tablets and capsules

administered with an 8-oz. glass of water may be inconvenient for some patients. For example, a

very elderly patient may not be able to swallow a daily dose of antidepressant. An eight year- old

child with allergies could use a more convenient dosage form than antihistamine syrup. A

Schizophrenic has difficulty to take conventional tablet under his or her tongue to avoid their daily

dose of an atypical antipsychotic. Immediate release tablets are a perfect fit for all of these patients.

Recently Fast dissolving formulation is popular as NDDS because it is safest, most convenient and

an economical method of drug delivery having the highest patient compliance. [1,2,3]

Immediate

release tablet are disintegrate or dissolve rapidly in the patient’s mouth offers the ease of oral

administration and benefits of increased patient’s compliance and for young children, the elderly

and patients having swallowing difficulties(dysphagia) and tremor of extremities or mentally

retarded. When tablet introduction into the mouth, these tablets dissolve or disintegrate in the

mouth in the absence of additional water. FDT are designed to dissolve in the saliva usually within

<60 seconds. [4]

FDT are prepared by various techniques, mainly direct compression, lyophilization, moulding,

spray drying, sublimation [5,6,7,8]

etc. Usually superdisintegrants are added to facilitate the break up

or disintegration of tablet into smaller particle than can dissolve more rapidly[9,10,11].

MATERIALS AND METHODS

Atomoxetine HCl was obtained from Sun Pharmaceutical Industries Ltd., KyronTM

T-134 and

KyronTM

T-314 was obtained from Corel Pharma Chem., Ahmadabad, AmberliteTM

IRP-64 was

obtained from Rohm & Haas India Pvt Ltd., Crospovidone was obtained from Orbicular

Pharmaceutical Tech. Pvt Ltd., Microcrystalline Cellulose pH 102, Magnesium Stearate and Talc,

Aerosil were obtained from Orbicular Pharmaceutical Tech. Pvt Ltd., Aspartame was obtained from

Lesar Chemicals, Ahmedabad.

METHOD:

1. Identification

Determined by infrared absorption spectrophotometry. Compare the spectrum with that obtained

with the reference spectrum of Atomoxetine HCl.



UV Absorption Spectroscopy- Atomoxetine HCl solution of 100 µg/ml in 0.1N HCl was

scanned in the range of 200-400 nm. The λmax for Atomoxetine HCl was found to be 270 nm

as shown in the Figure 1

Figure 1: UV Spectra of Atomoxetine HCl

Melting Point: The melting point of Atomoxetine HCl was found to be 168 ℃±1℃ using

capillary method and was comparable with the standard value (168- 169℃)

Solubility: Atomoxetine HCl was highly soluble in water. This reiterates the fact that

Atomoxetine HCl is a BCS CLASS 1 drug

Organoleptic Properties: This includes recording of colour, odour and taste of the new drug

using descriptive terminology. Drugs generally have a character odour and taste.

Colour: White to practically white solid

Taste: Extremely bitter taste (As per review literature)

Odour: Odourless

2. Drug excipient compatibility study:

Fourier transforming infrared (FTIR)

Drug-excipients interaction play important role in the release of drug from formulation. FTIR

has been used to study the physical and chemical interaction between the drug and chemical

used. FTIR spectra of Atomoxetine HCl, drug resin complex (DRC) with KyronTM

T-134,

Crospovidone, KyronTM

T-314, Mannitol, Microcrystalline Cellulose pH 102 were recorded

using KBr mixing method on FTIR instrument of the institute (FTIR-8400S, Shimadzu,

Kyoto, Japan)



3. Spectrophotometric Method for Estimation of Atomoxetine HCl

The calibration curves for estimation of Atomoxetine HCl in the dissolution medium were

prepared in demineralized water (DM water), 0.1N HCl, pH 6.8 phosphate buffer.

Preparation of standard calibration curve for Atomoxetine HCl in demineralized water:

100 mg of Atomoxetine HCl was transferred in 100 ml volumetric flask. In that volume was adjusted

to 100 ml by addition of DM water to get stock solution of concentration 1000 µg/ml. The stock

solution was serially diluted with DM water to get drug concentration in range of 25-150 µg/ml.

The absorbance of the solution was measured against DM water as a blank at 270 nm using

double beam UV visible spectrophotometer. The graph of absorbance v/s concentration

(µg/ml) was plotted and data was subjected to linear regression analysis in Microsoft Excel®

.

The results of standard curve preparation are shown in Table 1 and Figure 2 standard curve

for Atomoxetine HCl in DM water.

Table 1: Absorbance measurements for Atomoxetine HCl in DM water at 270 nm

Figure 2: Standard curve of Atomoxetine HCl in DM water at 270 nm

y = 0.005x + 0.004R² = 0.999

0

0.2

0.4

0.6

0.8

1

0 25 50 75 100 125 150 175

Avg. Abs. Linear (Avg. Abs.)Concentration (µg/ml)

Ab

sorb

an

c

Concentration

(µg/ml)

Absorbance

Test 1 Test 2 Test 3 Avg. Abs.

0 0.000 0.000 0.000 0.000

25 0.146 0.148 0.150 0.148 (±0.002)

50 0.278 0.279 0.275 0.276 (±0.002)

75 0.405 0.403 0.401 0.403 (±0.002)

100 0.534 0.532 0.530 0.532 (±0.002)

125 0.678 0.672 0.672 0.675 (±0.003)

150 0.817 0.813 0.814 0.815 (±0.002)

Correlation coefficient= 0.999

Absorbance = 0.0054*Concentration + 0.0047

Values in parenthesis indicate standard deviation with n=3



Preparation of standard calibration curve for Atomoxetine HCl in 0.1N HCl:

100 mg of Atomoxetine HCl was transferred in 100 ml volumetric flask. In that volume was

adjusted to 100 ml by addition of 0.1N HCl to get stock solution of concentration 1000

µg/ml. The stock solution was serially diluted with 0.1N HCl to get drug concentration in

range of 25-175 µg/ml. The absorbance of the solution was measured against 0.1N HCl as a

blank at 270 nm using double beam UV visible spectrophotometer. The graph of absorbance

v/s concentration (µg/ml) was plotted and data was subjected to linear regression analysis in

Microsoft Excel®

. The results of standard curve preparation are shown in Table 2 and Figure

3 standard curve for Atomoxetine HCl in 0.1N HCl.

Table 2: Absorbance measurement of Atomoxetine HCl in 0.1NHCl at 270 nm

Concentration

(µg/ml)

Absorbance


0 0.000 0.000 0.000 0.000

25 0.123 0.124 0.125 0.124 (±0.001)

50 0.241 0.237 0.239 0.239 (±0.002)

75 0.356 0.350 0.354 0.353 (±0.003)

100 0.488 0.487 0.491 0.489 (±0.002)

125 0.601 0.603 0.602 0.602 (±0.001)

150 0.739 0.737 0.741 0.739 (±0.002)

175 0.837 0.838 0.839 0.838 (±0.001)


Absorbance = 0.0048*Concentration- 0.0006


Figure 3: Standard curve of Atomoxetine HCl in 0.1N HCl at 270 nm

y = 0.004x - 0.000R² = 0.999

0

0.2

0.4

0.6

0.8

1

0 25 50 75 100 125 150 175 200


Ab

sorb

an

e



Preparation of standard calibration curve for Atomoxetine HCl in 6.8 pH phosphate

buffer:

100 mg of Atomoxetine HCl was transferred in 100 ml volumetric flask. In that volume was

adjusted to 100 ml by addition of 6.8 pH phosphate buffer to get stock solution of

concentration 1000 µg/ml. The stock solution was serially diluted with 6.8 pH phosphate

buffer to get drug concentration in range of 25-175 µg/ml. The absorbance of the solution

was measured against 6.8 pH phosphate buffer as a blank at 270 nm using double beam UV

visible spectrophotometer. The graph of absorbance v/s concentration (µg/ml) was plotted

and data was subjected to linear regression analysis in Microsoft Excel®

. The results of

standard curve preparation are shown in Table 3 and Figure 4 standard curve for Atomoxetine

HCl in 6.8 pH phosphate buffer.

Table 3: Absorbance measurement of Atomoxetine HCl in 6.8 pH phosphate buffer at 270

nm

Concentration

(µg/ml)

Absorbance


0 0.000 0.000 0.000 0.000

25 0.112 0.106 0.110 0.109 (±0.002)

50 0.227 0.228 0.229 0.228 (±0.001)

75 0.337 0.331 0.335 0.334(±0.002)

100 0.458 0.462 0.464 0.461 (±0.002)

125 0.587 0.589 0.588 0.588 (±0.001)

150 0.704 0.703 0.705 0.704 (±0.001)

175 0.806 0.808 0.802 0.805 (±0.002)


Absorbance = 0.0047*Concentration - 0.0054




Figure 4: Standard curve of Atomoxetine HCl in 6.8 pH phosphate buffer at 270 nm

4. Preparation of taste masking complex [12,13,14,15,16,17,18]

A. Preparation of drug raising complex (DRC) by batch method

The drug: resin was taken in the ratio 1:0.5, 1:1, 1:1.5 and 1:2. The resin (KyronTM

T-134,

AmberliteTM

IRP-64) was dissolved in demineralized water (qs) taken in container 1 and stirred for

30 to 60 mins. The pH of resin solution was adjusted to 6.5 to 7 by using 1M KOH. Now accurately

weighted drug (as per ratio) were added slowly and stirred for 4-5 hours. During stirring, pH of

solution was checked and adjusted to 6.5-7 by using 1M KOH. After 4-5 hours, the DRC was

separated by dispersion by filtration and washed with 3 portions of demineralized water. Complex

was dried at 50-60ºC and then evaluated for test and drug loading efficiency.

B. Characterization of DRC

The DRC solution was filtered through Whatman filter paper and the filtrate was dried to obtain

complex in powder form for characterization.

Drug-resin loading efficiency:

DRC was prepared using the above method. The filtrate obtained was diluted up to 3 times using

DM water. Absorbance was measured using UV double beam spectrophotometer at 270nm

Au/As=Cu/Cs........................ (1)

Where,

Au= Absorbance of unknown, As= Absorbance of standard

Cu= Conc. of unknown, CS= Conc. of standard

Drug content:

Drug content was determined by dissolving 20 mg equivalent of Atomoxetine HCl in 100ml

of 0.1N HCl and analyzing diluted sample by UV-visible spectrophotometer at λmax 270 nm

using 0.1N HCl as a blank.

y = 0.004x - 0.005R² = 0.999

0

0.2

0.4

0.6

0.8

1

0 25 50 75 100 125 150 175 200


Ab

sorb

an



In-vitro taste evaluation:

Taste of DRC was studied in-vitro by determining drug release in simulated salivary fluid (SSF)

(pH 6.8) to predict release in human saliva. DRC, equivalent to 20mg of API was placed in 10 ml

of SSF and shaken for 60 seconds. The amount of drug released was analyzed using UV visible

spectrophotometer at 270 nm. The ratio in which minimum of drug release takes place was taken as

optimized ratio for further study.

Molecular properties:

Molecular properties on complexation were studied by infrared spectroscopy (IR). IR spectra of

this sample were obtained by KBr disc method in the range of 4000-400 cm-1

with resolution 1 cm-1.

Drug release from DRC:

Drug release from DRC in 0.1N HCl was determined using a USP type II dissolution apparatus.

Accurately weighted DRC equivalent to 20 mg of Atomoxetine HCl was added to 900ml of 0.1N

HCl for 30 minutes (50 rpm, 37ºC). From that 5 ml of sample was withdrawn, filtered and

analyzed. Further 5 ml of 0.1N HCl was added to dissolution apparatus to maintain sink condition

C. Optimization of Drug Resin Complex:

Effect of temperature on dug loading:

The DRC stirred in 10 ml of demineralized water in a 100 ml beaker, was performed at 25-30ºC,

40ºC, 50ºC, 60ºC, 70ºC and 80ºC using temperature controlled magnetic stirrer for 4-5 hr. The

volume of filtrate was made up to 40 ml with demineralized water washing with DRC. The amount

of bound drug was estimated spectrophotometrically (at 270 nm) from the unbound drug in filtrate.

Effect of pH on drug loading:

The DRC stirred in 10 ml of demineralized water in a 100 ml beaker, was performed at different pH

1-8 using pH strip paper for 4-5 hr. The volume of filtrate was made up to 40 ml with

demineralized water washing with DRC. The amount of bound drug was estimated

spectrophotometrically (at 270 nm) from the unbound drug in filtrate.

Effect of soaking time of resin on drug loading:

The DRC stirred in 10 ml of demineralized water in a 100 ml beaker. Different batches with a

soaking time starting from 0 to 150 minutes were processed. The amount of bound drug was

estimated spectrophotometrically (at 270 nm) from the unbound drug in filtrate.

Effect of stirring time on drug loading:

The DRC stirred in 10 ml of demineralized water in a 100 ml beaker. Different batches with a

stirring time starting from 30 minutes to 6 hour were processed. The amount of bound drug was

estimated spectrophotometrically (at 270 nm) from the unbound drug in filtrate.



5. Optimization of Superdisintegrants in Atomoxetine Hcl Immediate Release Tablet Using 32

Full Factorial Design:

It is desirable to develop an acceptable pharmaceutical formulation in shortest possible time using

minimum number of man-hours and raw materials. Traditionally pharmaceutical formulations are

developed by changing one variable at a time approach. In addition to the art of formulation, the

technique of factorial design is an effective method of indicating the relative significance of a

number of variables and their interactions. The number of experiments required for these studies is

dependent on the number of independent variables selected and response measured for each trial.

A 32 randomized full factorial design was adopted to optimize the variables. In this design two

factors were evaluated, each at 3 levels, and experimental trials were performed at all 9 possible

combinations. The amounts of superdisintegrants, X1 (KyronTM

T-134) and X2 (Cross povidone),

were selected as independent variables. The disintegration time (Y1), Wetting time (Y2), and Drug

release at 5 min (Y3) were selected as dependent variables. The low (-1), medium (0) and high (+1)

are the values of X1 (KyronTM

T-134) and X2 (Cross povidone) respectively. All the possible

batches of factorial design are shown in Table 4.10, Table 4.11, Table 4.12, and Table 4.13. A

statistical model incorporating interactive and polynominal terms was utilized to evaluate the

response.

Y= b0 + b1X1 + b2X2 + b12X1X2 + b11X1X1 + b22X2X2 ................ (2)

Where Y is the dependent variable, b0 is the arithmetic mean response of the 9 runs, and bi is the

estimated coefficient for the factor X. The main effect (X1 and X2) represents the average result of

changing one factor at a time from its low to high value. The interaction term (X1X2) shows how

the response changes when two factors are change simultaneously. The polynominal term (X1X1,

X2X2) are included to investigate nonlinearity. Statistical treatment was carried out to the factorial

design batches using Microsoft Excel®

(2010), Statistica (version 8) and sigmastat (version 305).

Table 4: Different variable for factorial design

32 FULL FACTORIAL DESIGN

Independent variables Dependent variables

X1 X2 Y1 Y2 Y3

Conc. of

KyronTM

T-

314

Conc. of Cross

povidone

Disintigration

time

Wetting time Drug release

at 5 min.



Table 5: Selection of level for independent variable

Coded Value X1 (Conc. of KyronTM

T-

134)

X2 (Conc. of

Crospovidone)

-1 2 2

0 3 3

1 4 4

Table 6: Decoded and coded value for factorial design

Batches Coded value Actual value

X1 X2 X1 X2

B1 -1 -1 2 2

B2 -1 0 2 3

B3 -1 1 2 4

B4 0 -1 3 2

B5 0 0 3 3

B6 0 1 3 4

B7 1 -1 4 2

B8 1 0 4 3

B9 1 1 4 4

Table 7: Batches of 32 factorial design

Ingredients Batch (mg)

A1 A2 A3 A4 A5 A6 A7 A8 A9

DRC (1:1) eq.

40

eq.

40

eq.

40

eq.

40

eq.

40

eq.

40

eq.

40

eq.

40

eq.

40

KyronTM

T-

314

2% 2% 2% 3% 3% 3% 4% 4% 4%

CP 2% 3% 4% 2% 3% 4% 2% 3% 4%

Mannitol 56.0 54.5 53.0 54.5 53.0 51.5 53.0 51.5 50.0

Avicel 37.5 37.5 37.5 37.5 37.5 37.5 37.5 37.5 37.5

Aspartame

(2%)

3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0

Mg

Stearate

(1%)

1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5

Talc (2%) 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0 3.0

Aerosil

(1%)

1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5

Total weight of one tablet is 150 mg



6. Precompression Evaluation of Powder Blend [19,20]

:

Bulk Density(Db):

It is the ratio of total mass of powder to the bulk volume of powder. It was measured by pouring the

weighed powder (passed through standard sieve # 20) into a measuring cylinder and initial weight

was noted. This initial volume was called the bulk volume. From this the bulk density was

calculated according to the formula mentioned below. It is expressed in gm/ml and is given by

Db = M/Vb........................ (3)

Where, M is the mass of powder; Vb is the bulk volume of the powder

Tapped Density(Dt):

It is the ratio of total mass of the powder to the tapped volume of the powder volume was measured

by tapping the powder for 750 times and the tapped volume was noted. It is expressed in gm/ml and

is given by

Dt = M/Vt........................ (4)

Where, M is the mass of powder;

Vt is the tapped volume of the powder.

Carr’s Index (Compressibility) %:

It indicates powder flow properties. It is expressed in percentage and is given by

CI = [(Dt – Db)*100]/Dt ........................ (5)

Where, Dt is the Tapped Density of the powder

Db is the Bulk Density of the powder

Hausner’s Ratio:

Hausner’s ratio is an indirect index of ease of powder flow. It was calculated by the following

formula

Hausner’s ratio = Dt/D ........................ (6)

Where, Dt is the Tapped Density

Db is the bulk Density.

Lower Hausner’s ratio (<1.25) indicates better flow properties than higher ones.

Table 8: Effect of Carr’s Index and Hausner’s Ratio on flow property

Flow Character Carr’s Index (%) Hausner’s Ratio

Excellent <10 1.00-1.11

Good 11-15 1.12-1.18

Fair 16-20 1.19-1.25

Passable 21-25 1.26-1.34

Poor 26-31 1.35-1.45

Very poor 32-37 1.46-1.59

Very very poor >38 >1.60



Angle of Repose(θ):

The friction forces in a loose powder can be measured by the angle of repose (θ). It is an indicative

of the flow properties of the powder. It is defined as maximum angle possible between the surface

of the pile of powder and the horizontal plane.

θ = tan-1

(h/r)........................ (7)

Where, θ = Angle of repose

h = height of the powder cone in cm

r = radius of the powder cone in cm

Table 9: Effect of Angle of repose on flow property

Angle of Repose (θ) Type of Flow

<20 Excellent

20-30 Good

30-34 Passable

>35 Very poor

The powder mixture was allowed to flow through the funnel fixed to a stand at definite height (h).

The angle of repose was then calculated by measuring the height and radius of the heap of powder

formed. Care was taken to see that the powder particles slip and roll over each other through the

sides of the funnel.

7. Post compression Evaluation [19,20]

:

Diameter:

It was measured by verniercalipus. It is expressed in mm.

Thickness:

It was measured by verniercalipus. It is expressed in mm.

Hardness / Crushing strength:

Hardness or tablet crushing strength (force required to break a tablet in a diametric compression)

was measured using Monsanto Hardness tester. It is expressed in kg/cm2. Tablets require certain

amount of strength or hardness and resistance to friability, to withstand mechanical shocks of

handling in manufacture, packing, and shipping.

Weight Variation Test:

Twenty tablets were taken and their weight was determined individually and collectively on a

digital weighing balance. The average weight of one tablet was determined from the collective

weight. Not more than two tablets deviate from the percentage given below from the average

weight and none deviate by more than twice the percentage shown. The Pharmacopoieal

Specification of weight variation is given in table 10.



Table 10: Pharmacopoieal Specification of weight variation

Average Weight of Tablet(mg) % Deviation

80 mg or less ±10

80-250 ±7.5

250 or more ±5

Friability:

Friability of the tablet determined using friabilator. This device subjects the tablet to the combined

effect of abrasion and shock in a plastic chamber revolving at 25rpm and dropping a tablet at a

height of 6 inches in each revolution. Pre weighted sample of tablets was placed in the friabilator

and were subjected to the 100 revolutions. Tablet were de-dusted and reweighed, the loss in the

weight of tablet is the measure of friability and is expressed in percentage as

F = (Winitial – Wfinal) / Winitial*100........................ (8)

Content Uniformity:

Drug content from the tablets was determined by taking three tablets from each formulation.

Tablets from each formulation were accurately weighed and powdered in a mortar. Accurately

weighted a quantity of the powder equivalent to about 20 mg of Atomoxetine HCl dissolved in 100

ml of 0.1 N HCl in 100 ml volumetric flask. It was shaken for 15 min and filtered. The absorbance

of the resulting solution was measured at the maximum at about 270 nm and found the amount of

the Atomoxetine HCl using the calibration curve method.

In-Vitro disintegration time:

The In-Vitro disintegration time was determined using USP disintegration test apparatus. A tablet

was placed in each of the six tubes of the apparatus with lid on upper side and the time (second)

taken for complete disintegration of the tablet in distilled water at 37º ± 5ºC with no palatable mass

remaining in the apparatus was measured.

In-Vitro drug release:

Dissolution study was conducted to determine the drug release from the tablets using USP apparatus

type-II (paddle type) with the conditions as

Dissolution medium: 900 ml 0.1N HCl

Temperature: 37º ±0.5ºC

RPM: 50 rpm

A 5 ml sample was withdrawn at 5 minutes time intervals and replaced by an equal volume of 0.1

N HCl. Sample withdrawn was filtered through whatmann filter paper (0.45 micron). The amount



of Atomoxetine HCl released was analyzed at 270 nm using a Shimadzu UV 1800 double beam

spectrophotometer (Shimadzu, Kyoto, Japan)

Wetting time:

It is closely related to the inner structure of the tablets and to the hydrophilicity of the excipients. To

measure wetting time, five circular tissue papers of 10 cm diameter are placed in a petridish with a

10 cm diameter. 10ml of water containing eosin, a water soluble dye, is added to petridish. A tablet

is carefully placed on the surface of the tissue paper. The time required for water to reach upper

surface of the tablet is noted as a wetting time. To check for reproducibility, the measurement was

carried out six times and the mean value calculated.

Water absorption ration:

A piece of tissue paper folded twice was placed in a small petridish containing 6ml of water. A

weighed tablet was put on the paper and time required for complete wetting was measured. The

wetted tablet then re-weighed. Water absorption ratio, R was determined using following equation.

R = 100(Wa –Wb) / Wb........................ (9)

Wb = The weight of the tablet before keeping in the petridish

Wa = The weight of the tablet after keeping in the petridish

Stability Study ( Temperature Depedent):

FDA and ICH specifies the guidelines for stability testing of new drug products, as a technical

requirement for registration of pharmaceutical for human use (ICH guideline).The samples of

optimized batch were kept at 40°C ± 5°C and 75% relative humidity for one month in HDPE bottle.

The samples were withdrawn and analyzed for physical evaluation, assay and dissolution.

8. COMPARISON OF OPTIMIZED BATCH WITH MARKETED FORMULATION:

The developed optimized tablet formulation was compared with marketed formulations given in

Table 11. In vitro release profile was considered for comparison with marketed product. The in

vitro release profile of optimized formulation was compared with marketed formulations for

similarity Similarity factor (f2) and dissimilarity factor (f1).

Table 11: Marketed Formulations:

Brand Name Company

AXEPTA INTAS

8.1 Similarity factor (f2):

The Similarity factor (f2) given by SUPAC guidelines for a modified release dosage form was used

as a basis to compare dissolution profiles. The dissolution profile is considered to be similar when



f2 is between 50 and 100. The dissolution profile of products were compared using an f2 which is

calculated from following formula, Where, n is the dissolution time and Rt and Tt are the reference

(here is the dissolution profile of Atomoxetine HCl) and test dissolution value at time (t).

Dissolution profile of optimized batch was compared before and after stability study for calculation

of similarity factor.

𝒇𝟐 = 𝟓𝟎 × 𝐥𝐨𝐠 𝟏 + 𝟏

𝒏 𝒘𝒕 𝑹𝒕 − 𝑻𝒕

𝟐 𝒏𝒕=𝟏

−𝟎.𝟓 × 𝟏𝟎𝟎 ...... (10)

Where, n is the dissolution time and Rt and Tt are the reference (here is the dissolution profile of

Atomoxetine HCl) and test dissolution value at time (t). Dissolution profile of optimized batch was

compared before and after stability study for calculation of similarity factor.

Table 12: Similarity factor f2 and its significances

Similarity Factor (f2) Significance

< 50 Test and reference profiles are dissimilar

50-100 Test and reference release profiles are similar

100 Test and reference release profiles are identical

>100 The equation yields a negative value

8.2 Dissimilarity factor (f1):

The dissimilarity factor (f1) calculates the present difference between the two curves at each time

point and is a measurement of the relative error between the two curves:

𝒇𝟏 = 𝑹 −𝑻

𝑹 × 𝟏𝟎𝟎 ........................ (11)

Where, n is the dissolution time and Rt and Tt are the reference (here is the dissolution profile of

Atomoxetine HCl) and test dissolution value at time (t).

Dissolution profile of Optimized batch was compared before and after stability study for calculation

of similarity factor. The values should lie between 0-15. For curves to be considered similar f1

values should be close to 0.

9. ACCELERATED STABILITY STUDY OF OPTIMIZED BATCH

The purpose of stability is to provide evidence on the quality of a drug substance or drug product

which varies with time under the influence of a variety of environmental factors such as

temperature, humidity and light. The stability studies were carried out on the most satisfactory

formulations as per ICH guidelines Q1C. The optimized formulation sealed in vial with rubber cap

and kept in stability chamber maintained 40 ± 2°C and 75% relative humidity for one month. At the



end of studies were analyzed for drug content, wetting time, disintegrating time, hardness, friability

and in vitro drug release.

Results and Discussion:

Drug excipients compatibility study using FTIR:

Figure 5: FTIR Spectra of Atomoxetine HCl

Figure 6: FTIR Spectra of Atomoxetine HCl resin complex (DRC)

The Atomoxetine HCl exhibits peak due to C-N stretching of secondary amine (3500 – 3300 cm-

1). The infrared spectra of Atomoxetine HCl, Kyron

TM T-134 and Atomoxetine HCl- Kyron

TM T-

134 complex (DRC) are depicted. A peak at 3500 – 3300 cm-1

represents C-N stretching of

secondary amine. The absence of peak at 3500 – 3300 cm-1

in DRC confirms the complexation

drug with resin. The peak at 3362 cm-1

in DRC was corresponding to –OH stretching deign

absent, which signifies that during DRC formation here, was interaction of the amino group of

5007501250175022502750325037501/cm

20

30

40

50

60

70

80

90

100

%T

Atomoxetine HCl

5007501250175022502750325037501/cm

15

22.5

30

37.5

45

52.5

60

67.5

%T

Atomoxetine HCl resin complex

Secondary amine

group present

Secondary amine group

absent



Atomoxetine HCl with the carboxylic group of KyronTM T-134. Figure 6 was observed that there

were no changes in the main peaks in the FTIR spectra of pure drug and DRC.

Figure 7: FTIR Spectra of DRC + Formulation.

Figure 7 was observed that there were no changes in these main peaks in the FTIR spectra of a

mixture of drug resin complex and polymers. From the observation it was concluded that no

physical or chemical interactions of Atomoxetine HCl with other ingredients.

PRELIMINARY SCREENING OF TASTE MASK COMPLEX:

Characterization of DRC

Drug-resin loading efficiency

Filtrate diluted up to 40 ml

UV absorbance at 270 nm

Table 13: DRC ratio and corresponding absorbance for IER

Ratio (Drug:

Iron

Exchange

resin)

Absorbance (Aº) (Au)

KyronTM

T-134 AmberliteTM

IRP-64

1:0.5 0.450 (Dilution Factor 10) 0.156 (Dilution Factor 100)




5007501250175022502750325037501/cm

20

30

40

50

60

70

80

90

100

%TAtomoxetine HCl

Atomoxetine HCl resin complexAtomoxetine HCl+ Resin+ Superdisintegrant

Atomoxetine HCl



Calculation of drug resin loading efficiency:

Inputs:

Ratio= 1:0.5

Absorbance (KyronTM

T-134) = 0.450

Dilution = 10 ml

Equation:

Au/As=Cu/Cs

Au= Absorbance of unknown

As= Absorbance of standard

Cu= Concentration of unknown

Cs= Concentration of standard

Calculation:

Au = 0.450 ºA

As = 0.532 ºA

Cs = 100 µg/ml

Au/As=Cu/Cs

0.450/0.532 = Cu/100

Cu = (0.450/0.532)*100

Cu = 84.586 µg/ml

Cu = 84.586µg/ml * 10 (Dilution factor)

Cu = = 845.86µg/ml

Total filtrate = 40 ml

Cu in total filtrate

= 845.86µg/ml * 40 ml

= 33,834.58 µg

=33.83 mg

Total amount of bound drug = Total amount of used drug - Amount of unbound drug

Total amount of bound drug = 200 mg -33.83 mg

Total amount of bound drug = 166.17 mg

Drug loading Efficiency = Total amount of bound drug * 100 / Total amount of used drug

Drug loading Efficiency = 166.17 * 100 / 200

Drug loading Efficiency = 83.08



Table 14: Results of DRC ratio and corresponding absorbance

Ratio

(Drug:

Iron

Exchange

resin)

KyronTM

T-134 AmberliteTM

IRP -64

Absorbance

(Aº) (Au)

Drug

loading

efficiency

(%)

Absorbance

(Aº) (Au)

Drug

loading

efficiency

(%)

1:0.5 0.450 83.08 0.156 41.35

1:1.0 0.181 93.19 0.153 42.50

1:1.5 0.148 94.43 0.802 69.85

1:2.0 0.149 94.40 0.643 75.82

From the result Table 14 indicated that maximum drug loading efficiency 93.19% obtained in 1:1

ratio of Atomoxetine HCl: KyronTM

T-134. KyronTM

T-134 was gave the good drug loading

efficiency as compared to AmberliteTM

IRP -64.

Drug content

The results are shown in Table 15. It indicated that % drug content in DRC was found from 86.72

to 90.28 with using KyronTM

T-134 as a taste masking agent. As compared with KyronTM

T-134 to

AmberliteTM

IRP-64, which showed lesser amount of % drug content.

Table 15: Percentage drug content in DRC

Ratio (Drug: Iron

Exchange resin)

% Drug Content

KyronTM

T-134 AmberliteTM

IRP-64

1:0.5 86.72 47.85

1:1.0 90.28 58.32

1:1.5 87.25 65.30

1:2.0 88.47 70.04

In-vitro taste evaluation:

Drug release was observed in SSF (pH 6.8 phosphate buffer) from complexes with the drug-

polymer ratios of 1:0.5, 1:1, 1:1.5 and 1:2 were found to be result Table 16. According to result

Table 16 indicated that 1:1 ratio of DRC with KyronTM

T-134, which showed lesser amount of %

drug release (7.91%), were considered the best ratio DRC with significant masking of bitter taste

Table 16: Drug release of DRC IN pH 6.8 phosphate buffer (SSF)

Ratio (Drug:

Iron Exchange

resin)

% Drug release in pH 6.8 phosphate buffer

KyronTM

T-134 AmberliteTM

IRP-64

1:0.5 14.20 21.04

1:1.0 7.91 14.02

1:1.5 8.20 10.78

1:2.0 8.45 9.44



Molecular properties:

The Atomoxetine HCl exhibits peak due to C-N stretching of secondary amine (3500 – 3300 cm-1

)

in Figure 6. The infrared spectra of Atomoxetine HCl, KyronTM

T-134 and Atomoxetine HCl-

KyronTM

T-134 complex (DRC) are depicted. A peak at 3500 – 3300 cm-1

represents C-N stretching

of secondary amine. The absence of peak at 3500 – 3300 cm-1

in DRC confirms the complexation

drug with resin. The peak at 3362 cm-1

in DRC was corresponding to –OH stretching deing absent,

which signifies that during DRC formation here, was interaction of the amino group of

Atomoxetine HCl with the carboxylic group of KyronTM

T-134.

In Vitro Drug release from DRC:

Atomoxetine HCl release from DRC 1:1 (Atomoxetine HCl: KyronTM

T-134) was observed in

average salivary pH of 6.8 (Table 16), and at gastric pH of 1.2 (Table 17), separately. The DRC is

stable in salivary pH for a period of administration. The amount released is insufficient to impart

bitter taste while the formulation passes through the mouth to further parts of the gastrointestinal

tract. From the result Table 17 showed that 83-99% of Atomoxetine HCl was released within 30

minutes.

Table 17: Drug release from DRC 1:1 (Atomoxetine HCl: KyronTM

T-134)

Time(min) %cumulative drug release

0 0

5 83.43

10 87.55

15 90.78

20 96.78

25 99.38

30 99.98

Figure 8: Drug release from DRC 1:1 (KyronTM

T-134) in 0.1N HCl

0%

20%

40%

60%

80%

100%

0 5 10 15 20 25 30

CP

R

Time (mins)%cumulative drug release



OPTIMIZATION OF DRC

Effect of temperature on drug loading:

Table 18: Effect of temperature on DRC 1:1 (Atomoxetine HCl: KyronTM

T-134)

Temperature (ºC) % Drug binding

25-30 93.19

40 80.76

50 85.84

60 90.98

70 88.96

80 87.46

Efficient drug loading on KyronTM

T-134 occurred uniformly in the experimental temperature range

25-80 ºC as shown in Table 18. According to table indicated that maximum drug loading showed in

25-30 ºC temperature. There were no major changes % drug loading showed in result table 18.

Effect of pH on drug loading:

Table 19: Effect of pH on DRC 1:1 (Atomoxetine HCl: KyronTM

T-134

pH % Drug binding

1-2 7.52

2-3 32.36

3-4 44.89

4-5 61.88

5-6 75.57

6-7 93.19

7-8 73.158

Table 19 shows the effect of pH of resin dispersion on the %drug loading. The complexation was

enhanced with increasing pH from 5-8 (near to pKa of Atomoxetine HCl). The pH of the solution

affects both solubility and the degree of ionization of drug and resin. The maximum drug loading

was obtained in pH 6-7. The decreased complexation at lower pH is due to excess H+

ions in the

solution

Effect of soaking time of resin on drug loading:

Table 20: Effect of soaking time of resin on DRC 1:1 (Atomoxetine HCl: KyronTM

T-134)

Soaking time v(min) % Drug binding

0 40.18

10 67.68

20 82.98

30 93.19

60 86.46

90 74.44

150 76.4

Results of effect of soaking time on drug loading are shown in Table 20. The results reveal that a

30 min swelling time of KyronTM

T-134 in demineralized water gave the maximum Atomoxetine



HCl loading of 93.19%. This may result of maximum swelling and hydrating properties of KyronTM

T-134 that affect the rate of ion exchange. Less drug-loading efficiency may be observed in

unswollen resin matrix.

Effect of stirring time of resin on drug loading:

Table 21: Effect of stirring time of resin on DRC1:1 (Atomoxetine HCl: KyronTM

T-134)

Soaking time % Drug binding

30 min 87.52

1 hr. 89.16

2 hr. 89.46

3 hr. 91.76

4 hr. 93.19

5 hr. 92.40

6 hr. 90.26

The equilibrium ion exchange in solution occurs stoichiometrically and hence is affected by stirring

time. The percentage drug loading is checked a stirring time of 30 min to 6 hr. According to result

Table 21 showed that increasing the stirring time above 4hr did not further increase the

complexation values. Hence, contact time 4 hr between drug and resin could be optimized to

equilibrate the ion exchange process to achieve maximum drug loading. This study indicated that

the optimum ion exchange could be completed in a period of 4 hr.

FORMULATION OF IMMEDIATE RELEASE TABLETS FOR OPTIMIZATION OF

VARIABLES USING FACTORIAL DESIGN:

Pre-compression parameters of Factorial Batches:

The evaluation was carried out for the parameters like bulk density, tapped density, Carr’s index,

Hauser’s ratio and angle of repose as per the procedure described in Preformulation study. The

results are given in Table 22

The results of the Hauser’s ratio (less than 1.18) and the angle of repose (23º-29

º) reflected that the

powder blend had good flow property. So the flow of the prepared mass from the hopper was able to

fill the die completely for compression. The Carr’s index obtained was 11-20% so that showed good

compressibility of mass. After the lubrication the blend was ready for compression had good flow

property and excellent compressibility.



Table 22 Pre-compression parameters of Factorial batches

Formulation Bulk

density

(mg/ml)

Tapped

density

(mg/ml)

Carr’s

index (%)

Hauser’s

ratio

Angle of

repose ( º )

A1 0.463±0.03 0.529±0.03 12.47±0.01 1.14±0.01 26.37±0.04

A2 0.474±0.01 0.549±0.04 13.67±0.01 1.16±0.03 25.24±0.03

A3 0.438±0.02 0.501±0.02 12.44±0.03 1.14±0.02 27.03±0.02

A4 0.463±0.03 0.526±0.02 11.91±0.04 1.14±0.02 29.05±0.01

A5 0.461±0.03 0.534±0.03 13.50±0.01 1.16±0.04 25.09±0.02

A6 0.434±0.06 0.514±0.02 15.56±0.02 1.18±0.02 23.07±0.04

A7 0.465±0.03 0.525±0.03 11.46±0.03 1.13±0.02 26.56±0.04

A8 0.456±0.04 0.521±0.04 12.66±0.04 1.14±0.01 24.18±0.02

A9 0.449±0.04 0.526±0.03 14.47±0.06 1.17±0.02 27.26±0.04

Results are the mean of three observations ± SD(n=3)

The results of the Hauser’s ratio (less than 1.18) and the angle of repose (23º-29

º) reflected that the

powder blend had good flow property. So the flow of the prepared mass from the hopper was able to

fill the die completely for compression. The Carr’s index obtained was 11-20% so that showed good

compressibility of mass. After the lubrication the blend was ready for compression had good flow

property and excellent compressibility.

Post-compression parameters of Factorial Batches:

All the physical evaluation parameters were tested for all the batches including Weight variation,

Thickness, Hardness, Friability, Content Uniformity, Disintegration time, Wetting time and water

absorption ratio as a part of optimization. The results are given in Table 23

All the prepared tablets showed acceptable pharmaceutical properties. The hardness values of

formulations were within the range of 4-5 kg/cm2. Friability values of all formulations were less

than 1% was an indication of good mechanical resistance of the tablets. In determinations of tablet

weights, according to the IP less than 7.5% weight variation is acceptable in the tablet formulation

having average weight between 80-250. All formulations were found to be within IP limits as per

weight variation test. The uniformity of content was found to be within pharmacopoeial limits of

90-110%. All the batches have disintegration time within official limit of less than 3 min.



Table 23 Post-compression parameters of Factorial Batches

Formulation A1 A2 A3 A4 A5 A6 A7 A8 A9

Wt. variation*

(%)

154

±1.23

152

±1.09

151

±1.12

149

±1.17

151

±1.25

150

±1.32

148

±1.38

153

±1.15

149

±1.17

Thickness

(mm)

2.95

±0.33

2.98

±0.42

3.02

±0.64

3.12

±0.23

2.96

±0.43

3.05

±0.69

3.10

±0.63

3.02

±0.61

3.08

±0.55

Hardness

(kg/cm2)

4.0

±0.35

4.2

±0.44

4.3

±0.52

4.1

±0.39

4.0

±0.50

4.4

±0.64

4.2

±0.37

4.4

±0.38

4.3

±0.42

Friability

(%)

0.33

±0.27

0.39

±0.26

0.26

±0.37

0.35

±0.46

0.38

±0.56

0.27

±0.30

0.29

±0.25

0.26

±0.61

0.34

±0.69

Content

Uniformity(%)

98.23

±0.64

99.92

±0.32

99.54

±0.54

98.65

±0.38

99.88

±0.65

98.97

±0.42

99.75

±0.39

99.85

±0.55

98.25

±0.58

DT#

(sec)

52

±0.6

42

±0.7

38

±0.5

26

±0.3

20

±0.5

24

±0.4

36

±0.3

32

±0.1

42

±0.5

Wet. Time

(sec)

46

±0.3

38

±0.8

35

±0.5

22

±0.7

17

±0.6

21

±0.4

33

±0.7

27

±0.8

38

±0.5

WAR

(%)

84

±0.8

72

±0.9

62

±0.5

53

±0.7

92

±0.3

79

±0.8

82

±0.5

75

±0.6

70

±0.4

Results are the mean of three observations ± (n=3),

*Results are the mean of three observations ± (n=20) #Results are the mean of three observations ± (n=6)

All the prepared tablets showed acceptable pharmaceutical properties. The hardness values of

formulations were within the range of 4-5 kg/cm2. Friability values of all formulations were less

than 1% was an indication of good mechanical resistance of the tablets. In determinations of tablet

weights, according to the IP less than 7.5% weight variation is acceptable in the tablet formulation

having average weight between 80-250. All formulations were found to be within IP limits as per

weight variation test. The uniformity of content was found to be within pharmacopoeial limits of

90-110%. All the batches have disintegration time within official limit of less than 3 min.

Wetting time of immediate release tablet is another important parameter, which needs to be

assessed, to give an insight into the disintegration properties of the tablet. A lower wetting time

implies quicker disintegration of the tablet. Form the wetting time study it was reported that a linear

relationship exists between wetting time and disintegration time. By studying the water absorption

ratio, it was reported that as the disintegration time decreases water absorption ratio increases. All

the evaluated batches, formulation containing combination of KyronTM

T-314, CP used in different

concentration. From all the batches evaluated formulation containing A5 KyronTM

T-314: CP (3:3)

formulation gives good results i.e. showed minimum disintegration time and wetting time.



Table 24 In vitro drug release of all prepared batches

Cumulative percentage release

Time

(min.)

A1 A2 A3 A4 A5 A6 A7 A8 A9

0 0 0 0 0 0 0 0 0 0

5 68.35 65.98 53.36 87.32 95.92 84.23 59.32 75.28 78.45

10 70.69 70.36 65.39 88.05 96.07 86.17 75.45 79.64 78.27

15 76.57 72.58 69.86 88.56 96.27 87.54 77.52 81.85 79.95

20 79.68 74.96 71.88 90.17 97.37 88.29 78.25 82.57 81.96

25 83.23 75.65 73.63 92.58 98.56 89.05 80.57 83.85 83.77

30 87.36 77.65 75.69 94.92 99.98 89.27 82.90 85.69 86.93

Figure 9 In vitro release studies of A1-A5 Formulation for factorial batches

Figure 10 In vitro release studies of A6-A9 Formulation for factorial batches

In vitro release studies of Factorial bate:

From the dissolution profile of all the batches it was found that there was fast drug release at initial

state of dissolution. The initial rise in the drug release was dependent upon the affectivity and

0

20

40

60

80

100

120

0 5 10 15 20 25 30

A1 A2 A3 A4 A5Time (min)

CP

R

0

20

40

60

80

100

120

0 5 10 15 20 25 30

A6 A7 A8 A9

Time(min)

CP

R



concentration of superdisintegrant. The bursting effect of superdisintegrant showed rise (shoot) in

the drug release. From this study it was reported that decrease in the disintegration time showed

faster drug release. Among the nine batches A5 batch containing combination of 3% KyronTM

T-

314 and 3% CP in 3:3 ratio which is selected as optimized batch because of its lowest disintegration

time and highest drug release. Stability study was performed on formulation A5.

RESULTS OF STATISTICAL ANALYSIS

Results of dependable variables

Table 25 Results of dependable variables

Batch Disintegration

Time (sec.)(Y1)

Wetting Time

(sec)(Y2)

Drug release at 5

min.(%)(Y3)

A1 52±0.6 46±0.3 68.35

A2 42±0.7 38±0.8 65.98

A3 38±0.5 35±0.5 53.36

A4 26±0.3 22±0.7 87.32

A5 20±0.5 17±0.6 95.92

A6 24±0.4 21±0.4 84.23

A7 36±0.3 33±0.7 59.32

A8 32±0.1 27±0.8 75.28

A9 42±0.5 38±0.5 78.45

From all above findings and results of dependable variables it was found that the batch A5

containing combination of 3% KyronTM

T-314 and 3% CP in 1:1 ratio which is selected as

optimized batch because of its lowest disintegration time, wetting time and highest water

absorption ration and 95.92% drug release at 5 min.

Results of 32 Factorial Design Batches:

32 factorial design was employed to study the effect of combination of independent variables i.e. X1

(KyronTM

T-134) and X2(Cross providence) on dependent variables Y1 (disintegration time), Y2

(Wetting time), Y3 (Drug release at 5 min.). A statistical model incorporating interactive and

polynomial terms was used to evaluate responses.

Y= b0 + b1X1 + b2X2 + b12X1X2 + b11X1X1 + b22X2X2........................ (12)

Where Y is the dependent variable, b0 is the arithmetic mean response of the 9 runs, and bi is the

estimated coefficient for the factor X. The main effect (X1 and X2) represents the average result of

changing one factor at a time from its low to high value. The interaction term (X1X2) shows how

the response changes when two factors are change simultaneously. The polynomial term (X1X1,

X2X2) are included to investigate nonlinearity. Statistical treatment was carried out to the factorial

design batches using Microsoft Excel®

(2010), Statistical (version 8) and sigma stat (version 305).



Table 26 Summary of results of regression coefficient

Coefficient for Disintegration Time

Model b0 b1 b2 b11 b22 b12 R2

P

FM 20 -3.66 -1.66 17 5 5 0.991 0.0024

p-Value 0.0003 0.0091 0.0714 0.0005 0.0177 0.0067 - -

RM 20 -3.66 - 17 5 5 0.971 0.0023

Coefficient for Wetting Time


P

FM 16.55 -3.5 -1.16 16.16 5.16 4 0.981 0.0085

p-Value 0.0019 0.0279 0.2745 0.0017 0.0421 0.0335 - -

RM 16.55 -3.5 - 16.16 5.16 4 0.970 0.0026

Coefficient for drug release at 5 min.


P

FM 93.97 4.226 0.175 -22.3 -7.22 8.53 0.988 0.0043

p-Value 1.61E-

05

0.024 0.872 0.001 0.025 0.006 - -

RM 93.97 4.226 - -22.36 -7.221 8.53 0.988 0.0004

FM: Full model, RM: Reduced model

The polynomial equation can be used to draw conclusions after considering the magnitude of

coefficient and the mathematical sign it carries (i.e., positive or negative). Table 27 shows the result

of the analysis of variance (ANOVA), which was performed to identify insignificant factors. The

high values of correlation coefficient for all variables (Table 26) indicate a good fit, i.e., good

agreement between the dependent and independent variables.



Table 27 Calculation for testing the model in portions

For Disintegration time

DF SS MS F F Cal. F Crit.

DF =(1,3)

Regression FM

RM

5 825.33 165.06 74.28 7.50 10.127

4 808.66 202.16 34.65

Error FM

RM

3 6.6666 2.2222 -

4 23.333 5.8333 -

For Wetting time


DF =(1,3)

Regression FM

RM

5 721.77 144.35 31.43 1.77 10.127

4 713.61 178.40 32.51

Error FM

RM

3 13.777 4.5925 -

4 21.944 5.4861 -

For Drug release at 5 min.


DF =(1,3)

Regression FM

RM

5 1503.256 300.6512 50.223 0.032 10.127

4 1503.072 375.768 82.848

Error FM

RM

3 17.958 5.9862 -

4 18.142 4.5356 -

DF: degree of freedom, SS: sum of squares, MS: mean of squares, F: Fischer’s ratio,

R2: regression coefficient, FM: full model, RM: reduced model.

Full and reduced model for Disintegration time:

The full model for disintegration time (equation 13) was developed by using the coefficient. The

significance level of coefficient b2 was found to be p = 0.0714, hence it was omitted from the full

model to generate the reduced model (equation 14).

The results of statistical analysis are shown in table 26. The coefficients b1, b12, b11 and b22 were

found to be significance at p<0.05, hence they were retained in the reduced model. The reduced

model was tested in portions to determine whether the coefficient b2 contribute significance

information for the prediction of disintegration time or not. The results for testing the model in

portions are shown in table 27. The critical value of F for α = 0.05 is equal to 10.127 (do = 1, 3).

Since the calculated value (F = 7.50) is less than critical value, it may be concluded that the b2 do

not contribute significantly to the prediction of disintegration time and therefore can be omitted

from the full model. The values for disintegration time (Table 25) for all the 9 batches (A1 to A9)

showed a wide variation (i.e. 20 to 52) indicate that the values of disintegration time strongly

dependent on the selected independent variables.



Full model: 20.00 - 3.66 X1 - 1.66 X2 + 5.00 X1X2 + 17.00 X1X1 + 5.00 X2X2 ..(13)

Reduced model: 20.00 - 3.66 X1 + 5.00 X1X2 + 17.00 X1X1 + 5.00 X2X2...........(14)

Here negative sign of X1 coefficient indicate that with increase in the concentration of KyronTM

T-

314, there was a decrease in the disintegration time of the product & negative sign of X2 coefficient

indicate that with increase in the concentration of cross povidone, there was a decrease in the

disintegration time. When compare to X2, X1 will decrease disintegration time.

Figure 11: Response surface plot for Disintegration time

From the response surface plot of disintegration time, it was observed that as X1 (conc. of

KyronTM

T-314) goes from -1 to 1 the disintegration time initially increases then decrease and

then again increases. Minimum disintegration time is observed for 0 value. For X2 the

disintegration time does not vary as the values change from -1 to 1. Hence X2 (conc. of Cross

povidone) does not have an impact.

Using 32

factorial design the regression analysis and response surface plot (Figure 11) it is

observed that KyronTM

T-314 with combination of Cross povidone is effective to decrease the

disintegration time which is desirable. From the full model generated for disintegration time, it

can be concluded that X2 should not be selected for lower disintegration time. The X1X2

coefficient suggests that the interaction between X1 and X2 has significant effect on disintegration

time. Combination of X1 and X2 is very effective to decrease the DT.

Full and reduced model for Wetting time:

The full model for wetting time (equation 15) was developed by using the coefficient. The

significance level of coefficient b2 was found to be p = 0.2745, hence it was omitted from the full

model to generate the reduced model (equation 16).






information for the prediction of wetting time or not. The results for testing the model in portions

are shown in table 27. The critical value of F for α = 0.05 is equal to 10.127 (df = 1,3). Since the

calculated value (F = 1.77) is less than critical value, it may be concluded that the b2 do not

contribute significantly to the prediction of wetting time and therefore can be omitted from the

full model. The values for wetting time (Table 25) for all the 9 batches (A1 to A9) showed a wide

variation (i.e. 17 to 46) indicate that the values of wetting time strongly dependent on the selected

independent variables.

Full model: 16.55 – 3.5 X1 – 1.16 X2 + 4 X1X2 + 16.16 X1X1 + 5.16 X2X2......(15)

Reduced model: 16.55 -3.5 X1 +4 X1X2 + 16.16 X1X1 + 5.16 X2X2.................(16)

Here negative sign of X1 coefficient indicate that with increase in the concentration of KyronTM

T- 314, there was decrease in the wetting time of the product & negative sign of X2 coefficient

indicate that with increase in the concentration of cross povidone, it will decreases in the wetting

time. When compare to X2, X1 will decrease wetting time.

Figure 12: Response surface plot for Wetting time

From the response surface plot of wetting time, it can be concluded that as X1 (conc. of KyronTM

T-314) goes from -1 to 1 the disintegration time initially increases then decreases and then again

increase. Minimum wetting time is observed for 0 value. For X2 the wetting time does not very as

the values change from -1 to 1. Hence X2 (conc. of Cross povidone) does not have an impact.

Using 32



T-314 with combination of Cross povidone is effective to decrease the

wetting time which is desirable. From the full model generated for wetting time, it can be

concluded that X2 should not be selected for lower wetting time. The X1X2 coefficient suggests



that the interaction between X1 and X2 has significant effect on wetting time. Combination of X1

and X2 is very effective to decrease the wetting time.

Full and reduced model for Drug release at 5 min.:

The full model for drug release at 5 min (equation 17) was developed by using the coefficient.

The significance level of coefficient b2 was found to be p = 0.872, hence it was omitted from the

full model to generate the reduced model (equ.18).




information for the prediction of drug release at 5 min or not. The results for testing the model in

portions are shown in table 27. The critical value of F for α = 0.05 is equal to 10.127 (df = 1, 3).

Since the calculated value (F = 0.032) is less than critical value, it may be concluded that the b2

do not contribute significantly to the prediction of drug release at 5 min and therefore can be

omitted from the full model. The values for drug release at 5 min (Table 25) for all the 9 batches

(A1 to A9) showed a wide variation (i.e. 53.36 to 87.32 %) indicate that the values of

disintegration time strongly dependent on the selected independent variables.

Full model: 93.97 + 4.226 X1 + 0.175 X2 + 8.53 X1X2 – 22.3 X1X1 – 7.22 X2X2….. (17)

Reduced model: 93.97 + 4.226 X1 + 8.53 X1X2 – 22.36 X1X1 – 7.221 X2X2 …… (18)

Here positive sign of X1 coefficient indicated that as the increase the concentration of KyronTM

T-

314, there was increase the drug release at 5 min. of the product & positive sign of X2 coefficient

indicate that with increase concentration of cross povidone, it will increase the drug release at 5

min. When compare to X2, X1 will increase drug release at 5 min.

Figure 13: Response surface plot for drug release at 5 min.



From the response surface plot of drug release at 5 min., it was observed that as X1 (conc. of

KyronTM

T-314) goes from -1 to 1 the drug release at 5 min. initially decreases then increases and

then again decreases. Maximum drug release at 5 min. is observed for 0 value. For X2 (conc. of

Cross povidone) goes from -1 to 1 the drug release at 5 min. initially decreases then increases and

then again decreases. As results of 0 values gives increase drug release at 5 min so, at 0 value X1

and X2 both give significant effect.

Using 32



T-314 with combination of Cross povidone is effective to increase the

drug release at 5 min which is desirable. The X1X2 coefficient suggest that the interaction between

X1 and X2 has significant effect on drug release at 5 min. Combination of X1 and X2 is very

effective to increase drug release at 5 min.

COMPARISON OF OPTIMIZED BATCH WITH MARKETED FORMULATIONS:

Optimized batch was compared with Axepta marketed product for dependable variables and in

vitro drug release.

Table 28 In vitro drug release of optimized batch (A5) and marketed product.

% Cumulative percentage drug release

Time (min.) A5 Axepta film coated

conventional tablet

0 0 0

5 95.92 8.39

10 96.07 13.35

15 96.27 21.65

20 97.37 26.65

25 98.56 30.26

30 99.98 34.56

Similarity Factor (f2) = 18.66

Dissimilarity Factor (f1) = 76.91



Figure 14: In vitro drug release of optimized batch and marketed product

Table 29 Comparison of optimized batch (A5) with marketed formulations

Batch DT (sec.) Wetting time

(sec)

Drug release

at 5 min (%)

Water abs.

Ratio (%)

A5 20 17 95.92 92

Axepta 270 220 8.39 70

After comparison of different parameters between optimized batch and marketed product, shown

in table 28, it was clearly seen that in all the way developed optimized batch (A5) is far better

than marketed product evaluated. It has least disintegration time and least wetting time, least

water abs. ratio and drug release as faster than marketed product.

Moreover, in vitro release profile of optimized batch (A5) was compared with marketed product

for similarity factor (f2) and dissimilarity factor (f1). For all the marketed product value for f2 are

less than 50 (18.66) and for f1 value are more than 15 (76.91) indicating no similarity between

optimized batch and marketed product which proved the superiority of optimized batch against

marketed product.

RESULTS OF ACCELERATED STABILITY STUDY:

In order to determine the change in in vitro release profile on storage, stability study of

formulation A5 was carried out at 40 ± 2°C in a humidity jar having 75% relative humidity.

Sample evaluated after one month showed no change in in vitro drug release pattern as shown in

Table 30.

0

20

40

60

80

100

120

0 5 10 15 20 25 30

F5 Axepta film coated conventional tablet

Time (min.)

CP

R



Table 30 In vitro Dissolution data of Batch A5 after Accelerated stability study

Time (min) %CPR (Initial) %CPR (After storage at

40 ± 2°C for one month)

0 0 0

5 95.92 90.63

10 96.07 92.56

15 96.27 93.43

20 97.37 95.57

25 98.56 96.90

30 99.98 97.25

Similarity Factor (f2) = 84.28

Dissimilarity Factor (f1) = 3.05

Figure 15: In vitro drug release of optimized batch A5 before and after Accelerated stability

study

Tablet Parameters of batch A5 after Accelerated stability study:

Table 31 Tablet parameters of batch A5 after Accelerated stability study

Parameters Zero time After one month

Hardness (kg/cm2) 4.0±0.50 3.9±0.23

Friability (%) 0.38±0.56 0.30±0.45

Content Uniformity (%) 99.88±0.65 99.15±0.65

Disintegration time (sec) 20±0.5 23±0.28

Wetting time (sec) 17±0.6 21±0.31

Water abs. ratio (%) 92±0.3 90±0.67

Results are the mean of three observation ± SD (n=3)

0

20

40

60

80

100

120

0 5 10 15 20 25 30 35

%CPR (Initial) %CPR (After storage at 40 ± 2°C for one month)

Time (min)

CP

R



From the results of evaluation of batch A5 after stability study, reveals that there is no significant

difference in to the drug content and in vitro release of drug when compare with the prior results

and the values of similarity factor was 84.28 (Table 30) indicating good similarity of dissolution

profile initially and after stability studies. Hence, the prepared Atomoxetine HCl immediate release

tablet was found stable at 40±2°C/75%RH.

CONCLUSION:

During the last decade, immediate release tablet that disintegrate or dissolve rapidly in the patient’s

mouth offers the ease of oral administration and increased patient’s compliance. This is specially

useful for young children, elderly patients having swallowing difficulties (dysphagia) and mentally

retarded patients. When administered into the mouth, these tablets dissolve or disintegrate in the

absence of additional water. Thus taste masking of oral pharmaceutical has become a potential tool

to improve patient compliance and commercial success of the product. Ion exchange resins are

solid and suitably insoluble high molecular weight polyelectrolyte that can exchange their mobile

ions of equal charge with the surrounding medium. The resulting ion-exchange is reversible and

stoichiometric.

Molecular properties of resinate were studied using FTIR, which suggested complexation between

drug and resin. The complexes were successfully formulated in to immediate release tablets. Two

IER (KyronTM

T-134, AmberliteTM

IRP-64) were used in order to determine most suitable IER. It

can be concluded that KyronTM

T-134 in the ratio of 1:1 (Drug: IER) led to 93.19% drug loading

efficiency, 90.28% drug content and 7.91% drug release in phosphate buffer (SSF) having pH 6.8.

So, DRC can predict the drug release in SSF and better patient compliance. KyronTM

T-134 IER in

1:1 ratio offers successful taste masking of Atomoxetine HCl.

Three supersdisintegrant (SSG, KyronTM

T-314, and CP) were screened at different concentration

(2%, 3%, 4%) in order to determine most suitable superdisintegrant. Among these, KyronTM

T-314

and CP were selected and tried for further study.

To evaluate whether combination of superdisintegrants gave far better results or not, 32 full

factorial design was applied. Based on the results of different dependant variables and response

surface plot it was finalized that batch A5 containing 3% of KyronTM

T-314 and 3% of CP proved

as an optimal batch. The various formulations were compared with respect to in vitro disintegration

time and in vitro release profile. The formulation A5 was found to be palatable with in vitro

disintegration time of 20 sec and wetting time of 17 sec. Dissolution studies showed 99.98% of

drug release within 30 min. Finally we can conclude that immediate release tablet of Atomoxetine

HCl had been successfully prepared and evaluated.



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