An exploratory pilot analysis of the optimal pellet number in 100 mg of itraconazole capsule to maximize the surface area to satisfy the Noyes–Whitney equation

Abstract

Introduction Recalcitrant dermatophytoses is on the rise. With increasing microbiological resistance and clinical failures reported to terbinafine, itraconazole (ITR) is being increasingly used for the condition. ITR has an unpredictable bioavailability and quality variation among brands is known to affect clinical outcome. Bioequivalence to innovator brand is often not established and many spurious brands have flooded the market. Morphometric characteristics of the pellets, especially their count, size, and surface area impact dissolution of drug in the gastrointestinal tract, as per the Noyes–Whitney equation. It would be of value to clinicians to be able to differentiate good quality from poorly manufactured brands to achieve optimum clinical results, especially when rigorously done bioequivalence studies are not available. Aims We aimed to study the morphometric characteristics of various ITR brands and arrive at a pellet count which would present a surface area for absorption comparable to that of the innovator brand. Methodology Pellet count was done manually and size was estimated using a dermoscope. Surface area of each brand was calculated and comparisons done between different sub groups formed on the basis of pellet count. Results There is significant variation in the morphometric characteristics of pellets among different brands. A pellet count of ≥560 provides a surface area comparable to the innovator brand. Conclusion Pellet count of 560 or above provides an optimal surface area for absorption of ITR from GI tract. In the absence of bioequivalence studies with the innovator brand, this may be taken as a cut off for distinguishing poor quality ITR brands.