Formulation and Characterization of Extended-Release Nevirapine Solid Dispersions Running Title: Extended Release Nevirapine Solid Dispersions

The bioavailability of a drug is usually determined by its aqueous solubility and lipid permeability. Nevirapine is an antiretroviral drug that belongs to the BCS II with poor solubility but high permeability. This study was carried out to improve the dissolution of nevirapine and also to formulate extended-release nevirapine tablets. Nevirapine: PEG 4000 were combined in different ratios to produce physical mixtures and solid dispersions. Micromeritics studies were carried out on the particles of the solid dispersions and the physical mixtures. These physical mixtures and solid dispersions were then compressed into tablets. Micromeritic studies showed that the particles had fair to poor flow qualities, particle sizes were between 0 -20 µm. Organoleptic results showed round white tablets. The formulated tablets and the commercial brand passed the hardness test, PM1 and SD1only failed the friability tests. PM1 and the commercial brand displayed properties of an immediate-release tablet with disintegration times below 15 minutes and all drugs were released before 2 hours. Dissolution efficiency showed that the solid dispersion tablets with the highest concentration of polymer had the best DE. Compared with the physical mixture counterpart, the solid dispersions had a better dissolution and drug release. The PEG 4000 helped in extending the release of nevirapine drugs as seen by the extended-release of the nevirapine: PEG 4000 batches and the solid dispersion technique improved nevirapine dissolution