In vitro evaluation of a morphine polymeric complex: flowability behavior and dissolution study.

The purpose of this research was to perform a granulometrical and flow properties study of a morphine polymeric complex and determine the influence of 3 variables--particle size of complex, pH value, and ionic strength of the dissolution medium--on the dissolution behavior. The morphine-Eudragit L complex was produced in aqueous medium from morphine hydrochloride saturated solution and Eudragit L 30D diluted until 12% wt/vol and partially neutralized (40%). To determine the rheological behavior of the complex, several rheological tests were developed: bulk and tapped densities, Hausner ratio, angle of repose, and flow rate. The results corresponding to the technological study suggest that the 100- to 250-microm fraction can be considered as free flowing powder. In relation to the dissolution behavior of the complex, the results indicate that the ionic strength has been detected as the most influencing factor when values below physiological conditions are used. In conclusion, no technological problems for the production of further solid dosage forms are expected. Furthermore, no changes in the dissolution profiles of the complex have been detected when ionic strength values are inside the physiological range.