Influence of Milling Parameters on Crystal Morphology, Thermal Behavior, and Dissolution of Mesalamine Nanocrystals

The low aqueous solubility limits the therapeutic potential of both new and existing drug molecules. Mesalamine (MES), a primary therapeutic agent for inflammatory bowel diseases, has low aqueous solubility and incomplete dissolution in the colon; hence, it requires a high administered dose (maximum daily dose of 4.8 g/day). This study attempts to improve the dissolution velocity and solubility by designing MES nanocrystals.

MES nanocrystals were prepared using the dry ball milling (BM) process. MES nanocrystals (NCs) were prepared using Soluplus as stabilizer, and milling parameters were optimized to obtain the desirable particle size and other pharmaceutical attributes.

The prepared MES NCs were characterized to understand the influence of key milling parameters like time, speed, and stabilizer concentration. Variations in these parameters resulted in diverse morphologies, including rectangular bars, elongated hexagons, spheroids, and plates. Batch 29 (40/1/400) exhibited a plate-like crystal habit with a particle size of 435 nm and a PDI of 0.39, demonstrating an improved dissolution efficacy (84% in 60 min). Spectroscopic, microscopic, and thermal analyses confirmed the influence of ball milling on solubility, dissolution rate, particle size, and crystal habits.

The study outcomes could be useful for the successful scale-up and commercialization of drug products based on the dry BM platform technology.