This general information chapter Apparent Intrinsic Dissolution Testing Procedures for Rotating Disk and Stationary Disk 1087 discusses the determination of dissolution rates from nondisintegrating compacts exposing a fixed surface area to a given solvent medium. Compact, as used here, is a nondisintegrating mass resulting from compression of the material under test using appropriate pressure conditions. A single surface having specified physical dimensions is presented for dissolution. Determination of the rate of dissolution can be important during the course of the development of new chemical entities because it sometimes permits prediction of potential bioavailability problems and may also be useful to characterize compendial articles such as excipients or drug substances. Intrinsic dissolution studies are characterization studies and are not referenced in individual monographs. Information provided in this general information chapter is intended to be adapted via a specific protocol appropriate to a specified material.
Used in the private or public USP Performance test, dissolution testing plays an important role in both product development and quality assurance for nonsolution oral dosage forms. The dissolution procedure itself, as described in USP General Chapter Dissolution , is sensitive and specific but requires special care in execution. Results of a recent USP collaborative study of new Lot P Prednisone Reference Standard Tablets indicate much higher reproducibility (interlaboratory variance) than repeatability (intralaboratory variance) (1, 2). To improve reproducibility, the USP Biopharmaceutics Expert Committee recommends careful IQ, OQ, and PQ (mechanical calibration), aswellasaPerformanceVerificationTest (PVT); the latter two typically are performed at six-month intervals. Several variables such as shaft rotation speed, shaft and vessel alignment, basket/paddle height, and bath levelness have been cited as factors that contribute to high variability of the dissolution procedure. Missing from this list are factors relating to vessel dimension and irregularities, which are the subject of this report.