Utility of Different Lipids and Effect of Soya Lecithin on Sustained Delivery of Zidovudine via Biodegradable Solid Lipid Microparticles: Formulation and in-vitro Characterization

Background: Zidovudine (Azidothymidine, AZT) is widely used in the treatment of Acquired Immuno Deficiency Syndrome (AIDS) and related conditions, either alone or in combination with other antiviral agents to combat HIV. AZT is a Biopharmaceutical Classification System (BCS) class III drug and has various disadvantages. Thus, AZT is a potential candidate for delivery via lipid-based drug delivery system. Materials and Methods: In the present work, solid lipid microparticles (SLMs) of Zidovudine were developed for sustaining the drug release, to overcome or to reduce the hepatic metabolism and to ensure optimal bioavailability. A total of sixteen formulations of Zidovudine loaded solid lipid microparticles in two groups viz., one with tripalmitin and another with trimyristin were prepared by emulsion-solvent evaporation method. Results: The average particle size and entrapment efficiency of the prepared SLM varied between 5.48 μm-10.64 μm and 46.92 % and 58.39% respectively. The release of zidovudine from the SLM varied between 70.47% and 100% at the end of 24 hrs. 80% of the drug release which is required for obtaining the optimal therapeutic concentration was achieved by SLM 8. Conclusion: Formulation SLM 8 was considered best with maximum sustainability in the drug release along with maintaining therapeutic optimum. The formulation was found stable under stressed conditions.