Optimization and In Vivo Evaluation of an Oral Dual Controlled-Release Tablet Dosage Form of Insulin and Duck Ovomucoid

The objectives of the present study were to (1) optimize the release rate of insulin from compressed microparticulates and (2) compare the in vivo hypoglycemic effect of optimized insulin microparticulates with compressed enzyme inhibitor (duck ovomucoid) and without inhibitor. A 3-factor, 15-run Box Behnken design was used to construct polynomial models correlating the dependent and independent variables. Independent processing variables were rate of addition of the alcoholic Eudragit© L100 dispersion, volume of the antisolvent, and compression pressure. Responses were cumulative percent of insulin released from 1–6 hours. Insulin and ovomucoid release was simultaneously analyzed by high-performance liquid chromatography. They demonstrated variable release rates, which were optimized to the Higuchi's square root of time model to release the insulin and the inhibitor over 6 hours. The relationship between dissolution profiles and process parameters were demonstrated by contour and response surface plots. In vivo hypoglycemic effect was evaluated in rabbits in a 3-way crossover design. Cocompressed microparticulates of insulin and duck ovomucoid displayed a 3.2-fold greater hypoglycemic effect when compared with a similar preparation without ovomucoid. This study demonstrated the potential benefits of dosage forms with dual controlled-release mechanisms for both the protein and enzyme inhibitor.