Formulation and In-vitro Evaluation of Mucoadhesive Microspheres Loaded With Stavudine using Hydrophilic Macromolecular Polymers

Stavudine (D4T, thymidine) is an FDA-approved drug for clinical use in the treatment of HIV infection, AIDS and AIDS-related conditions either alone or in combination with other antiviral agents. The stavudine has a very short half life (0.8 to 1.5hr) with rapid absorption. The side effects of stavudine are dose dependent and a reduction of the total administered dose reduces the severity of the toxicity. Stavudine is typically administered orally as a capsule and oral solution. Dosage forms that are retained in the stomach would increase the absorption, improve drug efficiency and decrease dose requirements. The objective of the present study was to formulate and evaluate mucoadhesive microspheres of stavudine using a combination of sodium alginate with hydrophilic mucoadhesive polymers like carbopol 934 and chitosan. The prepared microspheres were evaluated for preformulation and post-formulation parameters. The prepared microspheres were found to be spherical, discrete and free flowing. The surface was found to be rough due to the entrapment of some part of the drug on the surface of the microspheres. The particle size was found to be in the range of 806.19 μm to 842.37 μm. The percentage encapsulation efficiency was found to be in the rage of 94.92 % to 98.16%. All the microspheres showed good mucoadhesive property with optimum swelling index. The in-vitro drug release was found to be in the range of 94.57% to 97.95% at the end of 12th hour. All the studies concluded that carbopol mucoadhesive microspheres are better than chitosan mucoadhesive microspheres loaded with stavudine in all the evaluated parameters.