Page 65 - Pharmaceutics III_ 02-06-01304_Fall 2025_ Pharm D_Electronic book
P. 65
Enteric Coating Evaluation:
• Resistance to gastric medium (no softening, cracking).
• Disintegration in intestinal fluid within specified time.
• Uniform coating thickness.
Sustained Release Coating Materials:
Type Example Mechanism
Water-insoluble Ethyl cellulose Diffusion control
Water-permeable HPMC, HPC Swelling control
pH-independent acrylic Eudragit RS, RL Controlled diffusion
Lipid materials Glyceryl monostearate, waxes Matrix release
Applications:
• Prolonged therapeutic effect.
• Minimized side effects.
• Improved patient compliance.
Microencapsulation in Tablets and Capsules:
Microencapsulation involves coating individual particles or droplets with thin polymer film.
Techniques:
1. Coacervation-phase separation.
2. Fluid-bed coating.
3. Spray drying.
4. Interfacial polymerization.
Applications:
• Controlled release.
• Taste masking.
• Protection from oxidation and moisture.
• Separation of incompatible materials.
Tablet Evaluation – Additional Physical Tests:
1. Uniformity of thickness:
64
