USP dissolution apparatus 3 (reciprocating cylinder): instrument parameter effects on drug release from sustained release formulations.

The United States Pharmacopoeia dissolution apparatus 3 (reciprocating cylinder) was evaluated with respect to effects of changes in instrument parameters on drug release rate from six hydrophilic matrix formulations and one coated-bead formulation. Reciprocation rate had the largest effect on time to 50% release for all matrix formulations. Top mesh size had an effect on release rate for those formulations having an erosion component to the drug release mechanism. Bottom mesh size had no effect on release rate. For the coated-bead formulation, no parameter had an effect on release rate. In an assessment of the hydrodynamics of the reciprocating cylinders, conditions equivalent to the 50 rpm paddle and 100 rpm basket were determined to be at the extreme low end of the available reciprocation rate range.