Dissolution enhancement of a poorly water-soluble antimalarial drug by means of a modified multi-fluid nozzle pilot spray drier

A spray drier with a modified multi-fluid nozzle was used to prepare microparticles of a poorly water-soluble antimalarial drug, artemisinin (ART), with the aim of improving its dissolution in water. ART was co-spray dried with a hydrophilic polymer, polyethylene glycol (PEG). The differential scanning calorimetry and X-ray diffraction studies showed that the crystallinity of ART decreased after spray drying. Compared to the physical mixture of ART and PEG, the amorphous phase of ART in the spray dried ART-PEG composites increased, which depended on the weight ratio of drug to polymer. The phase-solubility studies revealed that the aqueous solubility of ART was improved by the presence of PEG. The dissolution of ART from the spray dried ART-PEG composites was more rapid than that from their respective physical mixture and the original ART powder. For example, the dissolution of ART from the spray dried ART-PEG composite (1:6) was 6.5 times higher than that from the original ART powder in the first 30 min. In the mathematical modeling, the Weibull and Korsemeyer-Peppas models were found to best fit to the in vitro dissolution data and then the drug release mechanism was considered as the Fickian diffusion.