It is a crucial method in pharmaceutical research to assess the performance of formulations, especially those prone to supersaturation and crystallization. Traditional dissolution testing using the United States Pharmacopeia (USP) apparatus often falls short in predicting the behavior of complex formulations because it lacks absorptive sink conditions and doesn't mimic in vivo conditions.
To address these limitations, modifications have been made to the conventional dissolution apparatus, including the use of a two-compartment system with a donor and a receiver compartment separated by a membrane. In this setup, drug dissolution occurs in the donor compartment, and the appearance of drug in the receiver compartment is quantified to study absorption or permeation rates. However, current in vitro mass transport apparatuses have their own limitations, such as small membrane surface areas, slow mass transfer, and challenges in achieving detectable concentrations in the receiver compartment.
To overcome these limitations, a novel high-surface-area, flow-through absorptive dissolution testing apparatus has been developed. This apparatus employs a hollow fiber membrane module, which offers a large surface area per unit volume, enhancing mass transfer rates. The continuous flow of fluids on either side of the membrane minimizes the unstirred water layer barrier and provides controlled hydrodynamics, making it more similar to in vivo conditions. Fresh receiver fluid is continuously pumped to maintain sink conditions, and the flow-through setup allows real-time measurement of receiver concentration for a comprehensive analysis of solution behavior during dissolution.
The goal of this specific study was to use this absorptive dissolution testing apparatus to understand the dissolution-absorption behavior of supersaturating systems that undergo liquid-liquid phase separation (LLPS) with the formation of colloidal drug species. This method enhances mass transfer and the reservoir effect due to drug-rich nanodroplets.
Read also:
- Comparative Dissolution Profile Guideline
- Identifying Discriminatory Media and Its Role in Biopharmaceutical Studies
Resource Person: Lynne Taylor
