Determination of the Intrinsic Dissolution Rate (IDR) from a Powder and using a Miniaturized Wood’s Apparatus

Purpose. The objective of the study was to investigate the properties of several of the polymorphs of sulfathiazole using a new miniaturized powder intrinsic dissolution rate (IDR) apparatus, and to relate the IDR values to solubility.Conclusion. This study successfully demonstrated the application of the new method to simultaneously determine two important properties of the polymorphs of sulfathiazole: (1) intrinsic dissolution rate, and (2) pH-dependent solubility. Powder IDR measurements can be used in the early stages of drug development since they use up to 1000 times less API than traditional Wood’s rotating disk apparatus and are much faster.