Dissolution of Slightly Soluble Powders under Sink Conditions III: Transport of Drug Solution across Screens and Membrane Barriers

Abstract

Transport studies were carried out with a three-compartment apparatus developed for dissolution studies of slightly soluble powders under sink conditions. Effects of different pore-size screens and membrane barriers, propeller placement, and rate of agitation were investigated. Experiments were also carried out to study the effect of temperature and the presence of polysorbate 80 in the dissolution medium. Screens and barriers proved to be potential hindrances to the transport of drug molecules in solution. Increases in the barrier pore size and rate of agitation decreased the time for development of equilibrium across the barriers. The presence of an additional impeller, above and close to the barrier, was found to be much more effective than rate of agitation alone. An increase in the temperature of the system also lowered the equilibrium time, while the presence of polysorbate 80 in the dissolution medium increased the time for equilibration.