Page 56 - Pharmaceutics III_ 02-06-01304_Fall 2025_ Pharm D_Electronic book
P. 56
4. Wetting agents: sodium lauryl sulfate (improves dissolution).
5. Adsorbents: colloidal silica, Mg oxide, kaolin (for liquid absorption).
Controlled Release in Capsules:
Achieved by filling differentially coated pellets or matrix granules inside capsule shell.
• Immediate-release pellets: uncoated.
• Sustained-release pellets: polymer coated.
• Release controlled by diffusion or dissolution.
Pelletization for Capsules:
Methods:
1. Extrusion-spheronization: forms uniform spherical pellets.
2. Powder layering: builds drug on inert cores.
3. Solution/suspension layering: spraying solution onto cores.
Advantages:
• Uniform flow and packing.
• Better coating and controlled release.
• Reduced dose dumping.
Enteric-Coated Capsules:
Provide protection to drug and gastric mucosa; same principles as enteric-coated tablets.
Testing:
• Should resist 0.1 N HCl for 2 hours.
• Should disintegrate in phosphate buffer pH 6.8 within 60 min.
Capsule Shell Substitutes (Non-gelatin):
Used for vegetarian or religious requirements.
Examples:
• Hydroxypropyl methylcellulose (HPMC).
• Pullulan (from starch).
• Starch-based or carrageenan shells.
Advantages:
55
