Capsule Part 2
- Formulation of Hard gelatin capsule (HGC)
- TYPES OF MATERIALS FOR FILLING INTO HARD GELATIN CAPSULE
- LOCKING AND SEALING OF CAPSULE
- SOFT GELATIN CAPSULE
Formulation of Hard gelatin capsule (HGC)
• Gelatin – Finished HGC normally contain equilibrium moisture content 12-15%. The relative humidity (RH) 35-65% and temp. 15-25℃ during the storage of capsule.
• Opacifing agent :- used in HGC : titanium dioxide . opaque capsules are employed for either protection from light or to conceal the contents.
• Preservatives :- methyl paraben (lipid soluble) and propyl parabens(aqueous soluble)
Solubility limits of empty capsules :-
• Water resistance :- fails to dissolve in H2O at 20-30℃ in 15 minute.
• Acid solubility :- dissolve in less than 5 minutes in 0.5% w/w aqueous HCl at 36-38℃.
TYPES OF MATERIALS FOR FILLING INTO HARD GELATIN CAPSULE :-
• DRY SOLIDS :- powder, pellets, granules
• SEMI SOLIDS :- Suspensions or pastes
• LIQUIDS :- non-aqueous liquid
Capsule filling principle :-
• Auger fill principle :-
• Empty capsule :- rectifying unit
• Rectifier descends the capsule such that caps are turned up and bodies down.
• From rectifying unit these are placed one by one in filling ring kept on rotating mode.
• The lowering is rotated with a suitable speed and the hopper containing powdered drug is held over this ring
• The auger drives the drug into bodies
Vibratory fill principle :-
• The feed is placed in the feed hopper and the capsule bodies are passed under it
• A perforated resin plate is placed in the feed hopper
• Due the vibrations of the resin plate
• The powder flow freely through the pores into bodies
• Osaka machines follows this principle
• Piston –tamp principle :-
• These piston tamps alter the shape of powder by compressing the powder to form slugs
• These plugs are transferred into the empty capsule bodies with the application of slight pressure
• Finally the bodies are ejected from the machine. Compression force 50-200
Vacuum fill principle :-
• It consists of an open ended cylinder.
• The upper end of this is fitted with a piston.
• The open end is placed in bulk powder.
• Vaccum is applied & the piston is moved upward by sucking the predetermined amount of powder which results in filling of the cylinder.
Filling of HGC :-
• Punch method
• Hand filling or semi automatic capsule
• Automatic filling machine
Various filling machine :-
• Hofliger and karg
• Zanasi nigris
• Macofar SAS
LOCKING AND SEALING OF CAPSULE :-
BANDING :- placing gelatin color bands at meeting point of caps and the bodies
MOISTENING :- moistening the inner surface of caps with luke warm gelatin solution.
Spot welding :- spot welding the joints which leaves a ring like appearance at the point of sealing.
Thermal welding :- applying wetting solution. At the meeting point which causes lowering of M.P. at applied area. Finally they are sealed at a temp. 40-45℃.
By using coni-shap capsule :- grooves help to lock the caps with the bodies.
Finishing of capsule :-
• Cloth dusting :- capsule are rubbed with cloth.
• Polishing :- Pan polishing :- Acela-cota pan is used to dust and polish which is lined with cheese or a poly urethane cloth.
• Finishing of capsule :-
• Brushing :- Capsules are feed under soft rotating brush..
• Sorting :- roto sort :- 1,50,000 capsule/hr.
SOFT GELATIN CAPSULE (SGC) :-
Soft gelatin capsule are one piece hermetically sealed soft gelatin shells containing a liquid, suspension or semi solid.
It contains a drug that is encapsulated, dissolved, solubilized or suspended in a liquid vehicle having various shapes, size and colors
Best size and shape for convenient oral use in human is 9 minims round, 16 minim oval and 20 minim oblong.
Composition of SGC :-
GELATIN :- Ideal substance for capsulation. Bloom strength : 150-250gm, viscosity :- 2.5-4.5 cp and iron content not greater than 15 ppm.
PLASTICIZER :- Glycerin USP, Sorbitol USP, and their combination.
The ratio of dry plasticizer to dry gelatin measures the hardness of the capsule shell.
Hardness of gelatin shell
Dry weight of plasticizer / dry weight of gelatin
PRESERVATIVE :- Methylparaben : propylparaben (4:1), sorbic acid (0.2%)
COLORANTS :- FD&C water-soluble dyes, certified lakes, pigments.
OPACIFIER :- Titanium dioxide
FLAVORING AGENT :- Ethyl vanillin , essential oils.
FUMARIC ACID :- to aid solubility and to reduced aldehyde tanning of gelatin