Capsules are defined as the solid dosage form which contains the drug substances enclosed in the hard or soft container usually made up of the gelatin.
FORMULATION OF HARD GELATIN CAPSULES (HGC)
- On hydrolysis, gelatin gives 18 amino acids (glycine and alanine most common).
- There are two types of gelatin:
- a) TYPE A (Acid hydrolysed gelatin): Produced by acid hydrolysis (Isoelectric point near to pH 9.
- TYPE B (Base hydrolysed gelatin): Produced by alkaline hydrolysis (Isoelectric point near to pH 4.5.
Solubility limits of empty capsule:
- a) Water resistance : Fails to dissove in water at 20 – 30 Degree c in 15 minutes.
- b) Acid solubility : dissolve in less than 5 minutes in 0.5% aqueous HCL at 36-38 degree Celsius.
Equipment for filling of HGC :
- 1. Lilly park devis
- 8.Perry /Accofil
Equipment for de-dusting of HGC :
- Rotosort ; Mechanically sorts out unfilled joined capsules, loose caps
- Erweka KEA : For both de dusting and polishing
- Seidender equipment: uses a belt for visual inspection
FORMULATION OF SOFT GELATIN CAPSULES (SGC)
Soft gelatin capsules (SGC) contain a drug that is encapsulated dissolve, solublize or suspended in liquid vehicle
Composition of SGC:
- 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 (0.4 = hard, 0.6 = medium, 0.8 = soft).
3. Opacifier: Titanium dioxide in the concentration range 0.2- 1.2 %.
4. 1% Fumaric acid: To increase the acid solubility and reduce the aldehydic tanning of gelatin.
6. Essential Oils: 2% for odour and taste.
- Iron and content should not be more than 15PPM.
- Various coating like salol, shellac, cap also modifies the solubility of gelatin.
- It is an empirical gel strength measure, molecular weight of gelatin , which gives an identification of the firmness of the gel.
- It is measured in a bloom gelometer, which determine the weight in grams required to depress a standard plunger ( 0.5 inches in diameter) a fixed distance into 4 mm deep into 6.66% w/w gel held at 10 degree c for 17 hr.
- Bloom strengths in the range of 150-280 g are considered suitable for capsules.
- Viscosity is determined using 6.66% w/w of gelatin solution in water at 60 degree c using capillary pipette.The range Must be in 25-45 mill poise.
- Base absorption is defined as the minimum amount of base or vehicle in grams required per gram of solid drug to from a mixture which easily can be encapsulated in SGC.
- Base absorption : weight of base (grams)/ Weight of drug
- M/G Factor = (BA+S/D) * 16.23 minims
- BA = Base absorption Value
- S = Solid Drug
- D = Density of Mixture
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