On variability in test results of current in vitro dissolution tests.

ABSTRACT

An analysis of theoretical cumulative mass dissolved-time profile curves represented by Weibull distributions serves to illustrate a dependency of variability in test results of current in vitro dissolution tests, on slope of a profile curve and amount of a cumulative time-shift, at any given point of a dissolution process. As a result of the dependency, a case of high variability can be shown to be an exaggerated reflection of variability in an initial delay in onset of dissolution of a product (due to, e.g., needed dissolution of a gelatin shell or coating, disintegration, and/or wetting etc.), rather than a true reflection of variability of the product in rate of dissolution (subsequent to, e.g., the dissolution of a gelatin shell or coating, disintegration, and/or wetting etc.). The high variability would not be of a clinical significance.