Evaluation of dissolution techniques for orally disintegrating mini-tablets

Mini-tablets are suitable for paediatric as well as geriatric use since they may provide flexible and accurate dosing and administration. Due to the minute tablet size, there is a need for new standardized quality evaluation procedures and conventional techniques may have to be adopted. The main objective of the study was to evaluate different dissolution techniques for orally disintegrating mini-tablets. Dissolution tests using mini-paddle apparatus were compared with standard size paddle apparatus, and the effect of paddle rotation speed was evaluated. Also, the filter choice, and its impact on dissolution, was considered. Sodium salicylate was used as a model drug substance and was mixed with different size fractions of mannitol. The powder mixtures were compacted into 2 mm flat faced tablets. The mini-tablets were characterized regarding weight and content uniformity, tensile strength, friability, disintegration and dissolution. Similar dissolution profiles were obtained with both mini and standard equipment. The paddle rotation speed affected the dissolution profiles; a low paddle speed resulted in a slower dissolution. Furthermore, choosing a chemically inert filter will increase the likelihood of obtaining reliable and accurate results. An appropriately designed dissolution test using mini-paddle apparatus is required prior to further implementation in quality control procedures