Encapsulation_ Problem and Remedies

Encapsulation

Presentor : Bhushan Ghike

INTRODUCTION Capsule are solid dosage form in which one or more medicaments are enclosed in water

soluble, biodegradable shell made up of Gelatin.

Hard Gelatin capsule are also referred as “ Dry Filled Capsule” (D.F.C) as there shell is hard

and consist of two sections used for filling of dry material in body capsule.

Advantage of Capsule for oral administration

Easy to swallow due to their smooth and slippery nature

Easy to handle and carry

Can mask the unpleasant taste, color and odour of drug using tasteless shell

Better bioavailability than tablet and faster onset of action

The shell are physiologically inert and easily digest in the GI tract

Soft gelatin capsules

• Consist of a continuous gelatin shell surrounding a liquid core.- formed, filled, and sealed in one operation.

- oblong, spherical, elliptical in shape.

- The capsule shell consists of gelatin, water and plasticizer.

*Plasticizer makes the shell elastic.

e.g. glycerol, sorbitol and propylene glycol

Advantages:

1- Improved drug absorption.

2- Easy to swallow.

3- Avoids dust handling problems during manufacture

and better operator safety.

4- Overcome problems with manufacture (e.g. oils, low melting point drugs) as compressed tablet.

5- Dose uniformity for low-dose drugs.

6- Good product stability (drugs are protected against oxidative degradation by lipid vehicles and gelatin

shells).

Hard Gelatin Capsule It consists of two pieces in the form of cylinders:

the shorter piece “cap” and

the longer piece “body”.

The shells consist largely of gelatin, sugar and water.

• Gelatin Type B:produced by basic hydrolysis of bovine (cattle) bones

Type A: produced by acid hydrolysis of animal skins

• Water : contains 12 - 16 % moisture

• Dyes and Other Colorants

water soluble dyes – e.g. erythrosine

pigments – e.g. iron oxides , titanium dioxide (make

the capsule opaque to provide protection against light)

• Preservative

• Capsule shell Typically filled with dry solids

powders

granules

pellets

tablets

The fill weight = body volume x powder tapped bulk density

Dosator Tube Principle

Dosator consists of a tube, open at one end, within which is a moveable piston

The dosator is plunged into a bed of particulate solid contained in a hopper

Powder enters the open end of the dosator and is then consolidated by a downward movement of the piston to form a plug

The dosator is then withdrawn from the hopper, taking the plug with it, and is positioned over the body of the capsule shell.

The piston again moves downwards, ejects the plug into the capsule body and the upper part of the shell is then fitted

Cohesive powder is required with the aid of lubricant e.gMagnesium Stearate

Tamping Principle

Number of holes bored in dosing disc, all except one being closed by base plate

Powder flow into 1st hole and is compressed by a tamping pin 1

This hole is then moved to position two; further powder flows in and is compressed again, this time by tamping pin 2.

This is repeated until the last hole is reached after excess powder has been scraped off

The dosating disk positions the plug of powder over a capsule body

The plug is then ejected by a piston, and the upper part of the shell is fitted

The tamping pins are spring loaded to avoid the application of an excessive force. The resultant plugs are fragile and of high porosity and hence dispersion and dissolution of the contents after ingestion are facilitated.

Introduction to Capsule machine & Main assembly

Turret Assembly Station 1: capsule are oriented and loaded into cap/body bushes and separated

Station 2: Body bush segments moves out

Station 3: For pellet/tablet filling optional

Station 4: Powder filling

Station 5: Ejection of Unopened

Station 6: Capsule closing

Station 7: Ejection of filled capsule

Station 8: Cleaning of cap and body bushes by air & vacuum section

Capsule filling problem & RemediesProblem Probable cause Remedies

Capsule does not enter the magazine

Baffle plate not setting properly

baffle plate required to be open for the capsule to flow from hopper to reservoir. For big capsule (0/00) the gate require to be open more than small size capsule

Damage magazinebecause of damage marks on magazinecan be rectify by smoothening of magazine

Machine speed is slow

This also leads to entry problem of capsule in magazine slots. Ideally machine should be run at high speed. Generally machine speed below 50/60 spm would cause this problem.

Damage capsule

damage capsule prevents entry of othergood capsule from entering the magazinepass the blue plastic chord from the bottom hole of magazine or from slot of magazine and push all a way through so that capsule come out from the entry hole of magazine

Foreign particle in the magazine

look for any foreign particle like plastic piece, formulation traces etc. in the magazine slots. Clean the magazine with compressed air if required

Capsule filling problem & RemediesProblem probable cause remedies

capsule does not enter the rectifier block

capsule stored overnight and without climatic control

This may be due to improper room condition or the capsules having been affected by improper storage condition. In this case some of the capsules stick to each other preventing them to be transferred the magazine slots.

Magazine non alignment withrectifier block

Magazine alignment with the rectifier block could have shifted or not set right. Align to the rectifier block using gauge (Figure 1)

Capsule getting damage during loading

Alignment of rectifier block with bushes Verify visually if rectifier block is in alignment with cap/body bush. Use alignment gauge if any doubt. (Figure 2)

Capsule filling problem & Remedies

Problem probable cause remedies

Loss of cap during transfer

High vacuumVery high vacuum sometimes results in loss of cap.Try to reduce vacuum by adjusting throttle value but make sure that u do not reduce it so low that capsule non separation is observed.

Mis alignment of cap and body bush kindly check the alignment of cap and body bushvisually. Use alignment gauge if any doubt

Capsule non separation

Insufficient vacuum or incorrectvacuum pump

Kindly ensure Machine require proper capacity pump with delivery end pressure up to 24 inch of mercury. If you are using a pump with wrong capacity it will leads to non separation of capsule

Leakage through filtersin case of vacuum drops kindly check filters on the vacuum pump. Cleaned and/or replace it if required

cap body bush mis alignment

a mis alignment of cap and body bush can cause non separation. Check for all station if problem is general and for specific station if problem is at particular station.

worn out bushesif non separation occur in specific bushes and cleaning does not help, replace these bushes with new one.

Loss of spring tension at top slide

poor spring tension at the top side or sluggish movement of the top slide probably caused by pin results in improper closing of cap/body bush holder plate. Replace it


Target weight not achieved

incorrect target weight with respect to selected capsule size

Check for the variation in physical parameters like Tapped density, moisture content, particle size distribution & Flow properties of the formulation

Improper slug formation due to incorrect setting parameters

1) improper slug formation could be a results of insufficient tamping of the powder. Please ensure that tamping block 1 to 5 are place along the direction of rotation of dosing disc.2) If weight does not increase by tamping of tamping block the powder quantity in the dosing disc may be insufficient. This may leads to insufficient powder flowing in the holes of dosing disc and contributing less fill weight.3) improper selection of dosing disc for the respective formulation4) support springs of the some tamping piston might ever been crack or close during operations. such piston will not sustain the pressure and will not therefore not generate enough pressure to press the powder which results in low weight.

Insufficient binding if proper slug is not form, part of powder could be lost before delivery to the capsule

Poor flow of product

Poor flow of the powder in the dosing disc will results in insufficient powder flowing in the disc cavity.Depending on the nature of the formulation, a flap is used for pushing the powder to the areas where it does not flow.

formulation is sticky

contrary to the loos powder where slug is not getting formed or maximum tamping still does not form a proper slug, the powder could be sticky or hygroscopic.Check the tamping pins for any powder sticking to that

Capsule filling problem & Remedies

Problem probable cause remedies

weight variation

wrong selection of dosing disc thicknesskindly select proper dosing disc for filling of powder fully on to the capsule shell

Incorrect gap between1) dosing disc and supporting pad Gap is NMT 0.1 mm (fig:1)

2) Tamping pin and body bush to be maintained at 0.2 to 0.4 mm

3) dosing disc and wiper block Gap is NMT 0.1 mm (fig:2)

4) dosing disc and body bush to be maintained at 0.8 to 1.0 mm (fig: 03)


capsule lock length variation

excess joined length

check for the standard locking lengthlocking length of capsule from supplier# 00: 23.5 mm , # 0: 21.8 mm, #1: 19.5 mm, #2: 18.0 mm#3: 15.8 mm, #4: 14.5 mm, #5: 11.4 mm

Improper setting of closing plate

check for the gap between closing unitrubber sheet and capsules. The gap should be between 0.5 to 0.8 mm (fig:01)

Damage rubber sheet of closing plate

wear off of capsule closing unit rubber sheet specially at the point where capsule strike the sheet would lead this problem. Replace with new one.

Incorrect setting of closing plateThe flap should be visually parallel tothe cap bush lock plate.

Check to ensure that capsule are hitting the center of the rubber sheet and not he edge. If so capsule would slip off the edge and fail to lock properly.


Denting excess closing/lock length

excessive closing length setting will results in dent of the body dome. This creates resistance of the body to entre the cap lock portion. If this resistance is high (when slug is hard) it leads to denting.Ensure correct size disc is used and also ensure correct amount of dose is filled in capsule.

Telescopic

Mis alignment of cap and body bush

Misalignment of cap/body in one of bodybushes is the most common and primary cause of denting and telescopic. Align cap/body bush to bush gauge.

Closing pin not in center of body bushes

check pin straightness using gauge pin. If bent replace with new one

damage rubber sheet of closing plate

wear off capsule closing unit rubber sheet specifically at point where capsule strike the sheet would lead to telescopic. Replace if required

Encapsulation_ Problem and Remedies

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