Bioavibility Studies of Ocular Gels of Pilocarpine Microspheres

Egg albumin microspheres containing pilocarpine nitrate were prepared by heat stabilization method. Factors affecting size and encapsulation efficiency were optimized to obtain microspheres in the size range 1 to 12 μm to make them undetectable by eyes and big enough to entrap drug efficiently. Encapsulation efficiency was found to be 62.5%. In vitro release of drug from microspheres followed spherical matrix mechanism. Microspheric gels were prepared by triturating drug-loaded microspheres with Carbopol-940 gels. Biological response of microspheric gels and suspension were measured by reduction in intraocular pressure. Comparative evaluations were made by preparing plain gels of same drug concentration. Bioavailability parameters of all the formulations were studied and comparisons were made.