Pharmaceutical availability of papaverine hydrochloride from spray-dried products prepared with cellulose phthalates.

Papaverine hydrochloride suspensions in acetone/methanol (1:1) solutions of cellulose acetate phthalate, hydroxypropylmethyl cellulose phthalate HP 50 and HP 55 were spray-dried by means of Aeromatic, type Strea-1 device. Encapsulated particles were characterized by drug content, average volume-surface, flow rates, and porosities. Encapsulated products were compressed with and without additives (10% corn starch, 3% talc and 1.5% magnesium stearate). Dissolution tests of the compressed tablets in water were evaluated. The results of the dissolution of papaverine hydrochloride from directly compressed encapsulated particles were linearized by the Higuchi model, while for compressed tablets containing adjuvants a third root of undissolved drug vs. time model was used. The kind, quantity and technology of compressed tablets production influenced the drug release.