Taste Masking of Primaquine Phosphate: A Comparative Evaluation of Three Taste Masking Agents

The work involved taste masking of primaquine phosphate (PMQ), an intensely bitter drug used in the prevention and treatment of relapses of malarial infections caused by Plasmodium vivax and ovale. Drug and cation exchange resins viz, AmberLite™ IRP 64, 69, and 88 (IER 64, IER69, and IER88) were subjected to complex formation in 1:1 and 1:2 ratios using the shake flask method. Inclusion complexes of PMQ with hydroxypropyl beta cyclodextrin (HPBCD) were prepared to employ co-grinding, kneading, co-evaporation, and spray drying methods. Solid dispersions of PMQ with Eudragit E 100 (E 100) were prepared in various ratios by spray drying. In vitro, drug release studies of the composites were performed in 0.1N HCl and pH 6.8 phosphate buffer. The composites showing the least drug release in pH 6.8 buffer without compromising the release in an acidic medium were also evaluated for drug release in simulated salivary fluid (SSF). The selected composites were formulated into orally disintegrating tablets (ODTs) and subjected to human panel taste evaluation. PMQ-HPBCD spray-dried complex, PMQ-IER 69 (1:2) complex, and PMQ-E100 (1:4) dispersion exhibited drug release in decreasing order in SSF but > 85% release within 1 h in an acidic medium. Hence, these composites were formulated into ODTs. The human panel tasting indicated the most acceptable taste of the ODTs comprising PMQ-E 100 dispersion followed by PMQ- IER 69 (2) complex, and lastly PMQ HPBCD complex. The PMQ-E100 dispersion-based ODTs could thus be a promising option for treating pediatric and geriatric patients with PMQ.