PREPARATION AND EVALUATION OF MUCOADHESIVE MICROCAPSULES OF ACYCLOVIR FOR ORAL CONTROLLED RELEASE

Abstract

Mucoadhesive microcapsules become adhesive on hydration and hence used for localizing the drugs to a particular target site of gastrointestinal tract (GIT) for prolonged period of time. Acyclovir [9-(2-hydroxyethoxymethyl) guanine] (ACV), is a synthetic purine nucleoside analog derived from guanine which is considered as the first agent to be licensed for the treatment of herpes simplex virus (HSV-1, HSV-2) infections and is the most widely used drug for infections such as cutaneous herpes, genital herpes, chicken pox,varicella zoster infections through interfering with DNA synthesis and inhibiting viral replication. Acyclovir has low bioavailability of 20%. It undergoes hepatic metabolism and its elimination half-life is 2-3hrs.Therefore the possible way by which this can be overcome is by formulating a sustained release mucoadhesive formulation.The mucoadhesive microcapsules of Acyclovir (F1-F16) were successfully prepared by Emulsion Solvent Evaporation method using polymers Sodium Alginate, Sod CMC, HPMC K4M and Carbopol 940. FTIR studies did not reveal any significant drug interactions.The prepared microcapsules had good spherical geometry with smooth surface as evidenced by scanning electron microscopy. The average particle size of mucoadhesive microcapsules of Acyclovir was found to be in the range of 289±2.28µm to 399±3.12µm.The formulation F16 was selected as the best formulation as it showed Percentage yield (97.6%), Entrapment efficiency (87.5±0.32%), Mucoadhesion test (70±3.32%)  and  Swelling index (74.6±2.24%). The In-vitro drug release (F16) was found to be (98.12±0.24 %) at the end of 12 hours. The formulation F16 followed Zero order kinetics with Higuchi mechanism. The optimized formulation F16 stored at elevated temperature such as 25⁰C/60% RH and 40⁰C/75% RH for 3 months. The results of accelerated stability studies revealed no significant changes were observed in drug entrapment efficiency, swelling index and invitro of drug release studies. Based on all the above evaluation parameters it was concluded that the formulation F16 acyclovir microcapsules was found to be the best formulation among all the formulations and can be used in the treatment of herpes simplex virus (HSV-1, HSV-2) infections.