ABSTRACT
Dissolution testing is an in vitro procedure designed to discriminate important differences in components, composition, and=or method of manufacture between dosage forms (1). A dissolution test for solid oral dosage forms, utilizing a rotating basket apparatus, was first included in the United States Pharmacopeia (USP) 18 in 1970. The current USP (2) includes general methods for disintegration, dissolution, and drug
release. The disintegration and dissolution tests are intended primarily for immediate release solid oral dosage forms, the former controlling the time taken for a tablet or capsule to break down and the latter controlling release of the active ingredient(s). The drug release test is intended for application to modified release articles including delayed and extended release tablets; seven apparatus are described, the choice being based on knowledge of the formulation design and actual dosage form performance in the in vitro test system. Specific guidance is given with regard to the utility of Apparatus 1 (basket) or 2 (paddle) at higher rotation frequencies, Apparatus 3 (reciprocating cylinder) for bead-type delivery systems, Apparatus 4 (flow cell) for modified release dosage forms containing active ingredients of very limited solubility, Apparatus 5 (paddle over disc) or Apparatus 6 (cylinder) for transdermal patches, and Apparatus 7 (reciprocating disc) for transdermal systems and non-disintegrating oral modified release dosage forms. The usage of the various apparatus across all modified release dosage forms described in the current USP is shown in Fig. 1.
