Mechanistic insights into dissolution enhancement of co-spray dried meloxicam with chitosan and solubilization agent

This study presents a co-spray drying formulation approach to enhance the dissolution rate of meloxicam (MX), a poorly soluble model drug, by combining it with chitosan (CHIT) and sodium lauryl sulfate (SLS). Ternary formulations were prepared using both mini- and medium-scale spray dryers and compared with physical mixtures and RAW MX. In vitro dissolution testing revealed a significant increase in the release rate, with up to 80% of MX dissolved within 5 min. A comprehensive set of solid-state analytical techniques (XRPD, FTIR, and confocal Raman microscopy) revealed subtle changes in MX crystallinity and hydrogen-bonding interactions with both excipients. These findings support three key mechanisms contributing to enhanced dissolution: (i) reduced agglomeration of MX via adsorption onto the CHIT surface, (ii) improved wettability of products due to the presence of SLS, and (iii) increased matrix hydrophilicity facilitating drug-medium contact. The successful scale-up using a medium-scale spray dryer demonstrated the feasibility of this strategy for industrial application. The results highlight co-spray drying with functional excipients as a robust and scalable method for improving the biopharmaceutical performance of poorly soluble drugs. The simple co-spraying of the CHIT dispersion with the drug solution, without the need to dissolve the chitosan, is additional advantage.