International Journal of Pharma and Bio Sciences V1(2)2010 ... · interactions of paracetamol with...

International Journal of Pharma and Bio Sciences V1(2)2010

MOLECULAR INTERACTION STUDY OF ANTIBIOTIC

DOXYCYCLINE HYCLATE WITH LINOLEIC ACID

1

www.ijpbs.net Medicinal Chemistry

C.ROUMANA*1AND G. VELRAJ1

1Department of Physics, Periyar University, Salem-11.

* Corresponding Author [email protected]

ABSTRACT Molecular Interaction of antibiotic Doxycycline hyclate with unsaturated fatty acid, the linoleic acid

have been investigated using dilute solution viscosity and ultrasonic techniques at ambient temperature

303 and the physiological temperatures 310 and 313K in the presence of solvent ethyl methyl ketone.

The temperatures 310 and 313K are favouring interaction between Doxycycline Hyclate and linoleic

acid. The interaction between the antibiotic and the linoleic acid is found on the basis of solute-solute

and solute-solvent interactions. Thus the antibiotic exhibits high structural specificity and the structure

of the drug play an important role in exhibiting liphophilic interactions.

KEYWORDS Interaction, Linoleic acid, antibiotic, viscosity, ultrasonic

INTRODUCTION

The growing interest in the study of molecular scale

interactions of drug with other biomolecules is due

to the fact that these interactions are the key to

understand the structural or characteristic property

of drug molecules. The non-newtonian Doxycycline

hyclate a member of tetracycline antibiotic family

exhibits metalloproteinase activity and shows

equilibrium between bioactive zwitterionic and non-

ionic conformation at physiological temperatures1.

In the presence of organic solvent Doxycycline

hyclate acquires non-ionic form which is suitable

for lipid solubility of the drug and penetrates the

cell membrane2. These interactions may leads to

antibiotic resistance and toxicity. Thus it is of

specific interaction type.

Therefore, the interaction between macromolecule

Doxycycline hyclate and the fatty acid, linoleic acid

may be attempted through dilute solution

viscometric technique and ultrasonic the effective

and established techniques to identify the solute-

solute and solute-solvent interactions in system.

Arun Kumar Misra et.al.,3 have attempted the

interactions of paracetamol with fatty acids through

viscometric technique. Conformity of

macromolecular interactions was reported by many

workers using ultrasonic technique4,5

. Varadarajalu

et.al.,4 and Singh and Singh

6 have suggested the use

of ultrasonic velocity and viscosity measurement

for investigating polymer interactions. In the

mailto:[email protected]


www.ijpbs.net 2 Medicinal Chemistry

present study, the viscosity and ultrasonic

techniques were employed in Doxycycline hyclate /

Linoleic acid blends at the ambient temperature

303K and physiological temperature 310 and 313K.

MATERIALS AND METHODS

Doxycycline hyclate (Dox) (C22H24N2O8. HCl.1/2

C2H5OH.1/2H2O) of molecular weight 512.94

manufactured by Yangzhou huashu winsome

pharmacy Co.Ltd., China and supplied by Prime

Research laboratory (India) Pvt. Ltd., Chennai and

Linoleic acid of molecular weight 280.5

manufactured by merck specialities private Ltd.,

have been employed in the present study. 0.1%w/v

binary solutions of Doxycycline hyclate and

unsaturated linoleic acid (La) in ethyl methyl ketone

(EMK) were prepared. Using the binary solutions,

the blends of Dox/La of different compositions

were prepared. The relative viscosities were

measured using an Ubbelohde suspended level

viscometer for the binary solutions and blends of

Dox/La at temperatures 303K, 310K and 313K. The

Ultrasonic velocity measurements have been

performed by an ultrasonic interferometer operating

at frequency 2MHz and supplied by Mittal

enterprises New Delhi. The temperature is

maintained at 303K, 310K and 313K by a

thermostat, with a thermal stability of ±0.05°C. The

density of the solutions was measured using 10ml

standard specific gravity bottle.

THEORY

Viscometric Analysis

Based on additive law Huggin’s equation expresses

the specific viscosity (ηspe) as a function of

concentration if one of the components is alone in

solution,5

ηspe/C = [η] + KH [η]2 C -------- (1)

Where [η] is the intrinsic viscosity and K’ is the

Hugggin’s constant. If KH = b/[η]2, where b is the

interaction coefficient, then eq. (1) becomes

ηspe/C = [η] + bC ------------ (2)

Chee [7]

extended the Huggin’s equation for a

ternary system of solute A, solute B in common

solvent and gave the interaction parameter,

µ = ∆B / {[η]B - [η]A}2

---- (3)

Where [η]A and [η]B are the intrinsic viscosities for

the pure component solutions.

The blend is miscible if µ ≥ 0 and immiscible when

µ < 0.

Sun. et. al.,8 Suggested a new criterion, ‘α’

Km in the Huggin’s coefficient for the blends.

According to Sun. et. al’s for a ternary system, there

are three types of interaction that might contribute

to the value of Km: long-range hydrodynamic

interaction of pairs of single molecules given by

Km1; the formation of double molecules given by

Km2; and intermolecular attraction or repulsion

given by Km3. Thus, the overall Km turns out to be

Km = Km1 + Km2 +Km3 ----------(4)

In the absence of strong special interactions that would encourage aggregation, and at

sufficiently low concentrations, the second term Km2 can be neglected. Reabbrevating, Km3 as α and

rearranging the final equation then yields. α = Km – Km1 ----------------(5)

2 22 2

2

2A A B B A B A BA B A Bm

A BA B

K W K W K K W WK

W W

-------------------------(6)

Km is the experimentally obtained Huggins constant. The parameter α indicates the nature and

strength of the intermolecular interaction (α>0, attraction; α<0, repulsion). The sign of the parameter

α can be used to predict the solute-solute interaction, when α≥0 and α<0 indicates blend-solvent

interaction.

Jiang and Han9 revised Sun’s criterion by substituting an expression for total interaction

existing in the system Km, illustrated as in equation (7).

2 22 2

2

2A A B B AB A BA B A Bm

A BA B

K W K W K W WK

W W

-----------------------(7)

Then the new criterion β for the resultant interaction



2

2 A BA B

A BA B

K W W

W W

-----------------------------------(8)

Where 1

2AB AA BBK K K K

The criteria β≥0 indicates solute-solute interactions and β<0 is for blend-solvent interactions.

Ultrasonics Studies

Ultrasonic velocity (u) and density (ρ) are the observed parameters. These parameters were

employed to calculate the parameters,

Adiabatic Compressibility β = 1/uρ m2/N --------- (1)

and Free length Lf = K √β Å -----------(2)

Where, k = 93.875 + 0.345* T *10^-8,

T = absolute temperature.

RESULTS AND DISCUSSIONS

Viscosity technique

The Huggin’s plots of ηspe/C versus concentration C for 0.1%w/v solutions of Doxycycline Hyclate,

and Linoleic acid and for the blends of Dox/La at compositions for temperatures 303, 310 and 313K

were drawn and shown in graphs 1, 2 and 3 respectively.

Graph 1 Graph 2 Huggins plot at 303K Huggins plot at 310K

The plot is used to find the interaction parameter

and intrinsic viscosity at 310K

The plot is used to find the interaction parameter

and intrinsic viscosity at 303K



Graph 3

Huggins plots at 313K

The values of viscometric parameters the, interaction parameter b, intrinsic viscosity [η] and the

Huggin’s constant KH for 0.1%w/v binary solutions at temperature 303K, 310K and 313K are

summarized in Table 1. The values of the derived, the chee7 parameter µ, the Sun.et.al,

8 parameter α

and the improved parameter β for the blends of Dox/La at 303, 310 and 313K are summarized in the

Table 2.

Table 1.

The values of b, [η], KH of 0.1% solutions of Doxycycline hyclate and

Linoleic acid in common solvent ethyl methyl ketone at 303, 310 and 313K

Temperature 303K 310K 313K

solutions [η]

dl/g b KH

[η]

dl/g b KH

[η]

dl/g b KH

0.1%

Doxycycline

hyclate

0.119 30.823 2191.31 1.565 -44.94 -18.34 1.342 -31.76 -17.63

0.1%

Linoleic acid 0.352 24.992 201.59 0.228 9.923 191.21 0.69 -21.47 -45.09

The plot is used to find the interaction parameter b and

intrinsic viscosity at 313K



The intrinsic viscosity [η] and the interaction parameter b of 0.1% solution of Doxycycline

hyclate and linoleic acid are positive at 303K. The positive value of b suggests the interaction

between the groups that are present in the system. The positive value of [η] indicates the solubility of

the solute components10

. At temperatures 310 and 313K, [η] remains positive but the interaction

parameter b negative suggesting the dominance of solute-solvent interactions.

Table 2. The values of µ, α and β parameters at 303, 310 and 313K

At 303K, the parameters α and β are negative at all compositions. These parameters claim

blend-solvent interactions as per the criteria. The above discussed positive and negative values of α, β

and µ are in agreement with the reported observations 11, 12

.

At 310K and 313K the parameters α and β are positive at all compositions and indicates the

solute-solute interaction of Dox/La. The chee parameter µ exhibits the contradictory results with α

and β at all temperatures and compositions. Similar contradictory behavior of µ is common and

available in literature.8

Compositions

Doxy :

linoleic acid

303K 310K 313K

µ α β µ α β µ α β

9:1 169.380 -1475.137 -238.93 -12.401 76.297 1.15 2.499 10.199 0.08

8:2 449.780 -1060.558 -313.81 -6.684 42.960 0.34 30.453 9.680 0.32

7:3 370.197 -792.566 -316.44 -7.360 92.518 6.27 -4.854 10.046 1.04

6:4 125.068 -594.145 -279.41 -12.401 128.007 15.33 -4.955 19.417 5.57

5:5 212.776 -475.761 -240.47 -12.738 259.404 51.11 -22.066 22.541 8.92

4:6 59.132 -358.636 -184.52 -7.544 51.003 8.15 -37.136 4.830 2.29

3:7 -161.824 -322.746 -143.75 -12.447 191.422 67.04 -1.119 17.174 9.93

2:8 -89.560 -218.900 -86.48 6.079 298.533 139.58 -5.901 28.158 15.27

1:9 -218.535 -216.280 -44.82 -6.301 270.841 150.06 -23.306 46.231 16.75



The behavior of free length with compositions at 303 K The behavior of free length with compositions at 310

K and 313K.

Ultrasonic technique

In order to further confirm the identified solute-solute interactions, the behavior of (u), (κ)

and (Lf) of Doxy/La blend solutions are depicted in graphs 4, 5, 6 and 7 respectively for the

temperatures 303K, 310K and 313K.

Graph 4 Graph 5

Behaviour of ultrasonic velocity and compressibility Behaviour of ultrasonic velocity and compressibility

Graph 6 Graph 7

Behaviour of free length Behaviour of free length

The behavior of ultrasonic velocity and adiabatic

compressibility with compositions at 303 K.

The behavior of ultrasonic velocity and adiabatic

compressibility with compositions at 310 K and 313 K.



From the behaviours of the parameters it is clearly evident that the variation is non-linear at

303K and indicates solute-solvent interactions in the blend. The criterion of linear behavior in u, κ

and Lf in the blend of Dox/La at temperatures 310 and 313K and establishes solute-solute interaction

between Dox and La. These observations are in agreement with the results obtained through dilute

solution viscometric technique. Varadarajulu et. al. 4 Singh and Singh et. al.,

6 somanathan et. al.,

13

Paladhi and Singh, 14

Murali mohan et.al.,15

have employed the Viscometric and Ultrasonic

techniques to identify the solute-solute and solute-solvent interactions in the polymer blends and

established the criteria.

The Doxycycline exhibits liphophilicity with non-ionic nature. The non-ionic confirmation of

Doxycycline hyclate predominates in organic solvent which provides a suitable structure for linoleic

acid to interact.

Figure 1: Stucture of Linoleic acid

Figure 2: Structure of Doxycycline Hyclate

The structure of Linoleic acid and

Doxycyline hyclate are shown in figure 1 and 2

respectively. The Linoleic acid interaction through

ester carbonyl C=O at hydroxyl of Doxycycline

hyclate at C3 through a dipole-dipole interaction

which makes the Doxycycline hyclate as an inactive

non-ionic molecule.

CONCLUSIONS In the present investigation the dilute

solution viscosity and ultrasonics successfully have

investigated the molecular interactions between

Doxycycline hyclate and linoleic acid. At

physiological temperature 310 and 313K the

interactions are favoured between Doxycycline and

Linoleic acid and these interactions are absent at

room temperatures. These molecular interactions are

at the physiological temperatures might leads to the

formation of antibiotic resistance and toxicity.



REFERENCES 1. John J. Stezowski, Chemical-structural

properties of tetracycline derivatives 1.

Molecular structure and conformation of the free

base derivatives, J. Am. chem soc., 98:19,

pp.6012-6018, (1976).

2. William. O. Foye, Principles of medicinal

chemistry, second edition, 38, (1981).

3. Arun Kumar misra, Manju misra, Gopal

madanlal Panpalia and Avinash keshav dorle,

Interaction study of Paracetamol with saturated

and unsaturated fatty acids Pharmaceutical

development and technology, 12, 423-428,

(2007).

4. A. Varada rajulu, R. Lakshminarayana reddy, S.

M. Raghavendra, S. Akheel Ahmed, Miscibility

of PVC/PMMA blend by the ultrasonic and

refractive index method Eur. Polym. J., 35 1183-

1186, (1999)

5. S. Ravichandran and K. Ramanathan, Ultrasonic

Velocity Studies and Allied Parameters of

Polyacrylamide/Polyethyleneglycol (600) and

Polyacrylamide/Polyvinylalcohol Blend Solution

at Low Concentrations, Polymer-Plastics

technology and engineering,47; 164-168, (2008).

6. Y.P. Singh and R. P. Singh, Compatibility

studies on polyblends of PVC with chlororubber-

20 and its graft polyblends by ultrasonics, Eur.

Polym. J., 20, 201-205, (1984).

7. K. K. Chee, Determination of polymer-polymer

miscibility by viscometry, Eur. Polym. J. 26 (4)

pp. 423-426, (1990).

8. Zhi nhua Sun, Wei Wang and Zhiliu Feng,

Criterion of polymer-polymer miscibility

determined by viscometry, Eur.Polym. J., 28, pp.

1259-1261, (1992).

9. Jiang, W.H., Han, S. J., An improved criterion of

polymer-polymer miscibility determined by

viscometry, Eur. Polym. J. 34, pp.1579-1584,

(1998).

10. M.L. Miller, The structure of Polymers,

Reinhold book corporation, New York 184,

(1966).

11. Murat Barsbay, Ali Guner, miscibility of dextran

and poly (ethylene glycol) in dilute aqueous

solutions. II. Effect of temperature and

composition, J. App.Polym.Sci, 100, pp.4587-

4592, (2006).

12. Ayse Z. Aroguz, Yasemin Kismir, Viscometric

study on the miscibility of

polystyrene/brominated polystyrene blends,

Eur.Polym. J., 43, 410-415, (2007)

13. N. Somanathan, A. Sanjay, V. Arumugam, J.

App.Polym.Sci, Compatibility studies on

polystyrene and poly-n-butyl methacrylate, 83,

2322-2330, (2002).

14. Paladhi R, Singh RP. Miscibility and interaction

studies on some aqueous polymer blend

solutions by ultrasonic and rheological

techniques, J. App.Polym.Sci 51, pp.1559-1565,

(1994).

15. Y. Murali mohan, P.S. Keshava murthy and K.

Mohana raju, Miscibility studies of hydroxyl-

terminated poly (butadiene) (HTPB) and

glycidyl azide polymer (GAP), J. Pure Appl

Ultrason. 27 119-124, (2005).

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