An Original Investigation into the Bioavailability Enhancement of Poorly Water-Soluble Drugs Using Nigerian Polymers and Natural Emulsifiers

Approximately 40 percent of drugs currently in development and a significant proportion of marketed agents exhibit poor aqueous solubility, representing a major pharmaceutical challenge that is particularly acute for Nigerian manufacturers without access to advanced solubilisation technologies. This study conducted an original investigation into bioavailability enhancement of poorly water-soluble drugs using Nigeria-derived natural polymers and emulsifiers as pharmaceutical excipients. A comprehensive pharmaceutical technology methodology was employed, encompassing excipient sourcing, characterisation, formulation development, and biopharmaceutical evaluation. Three Nigerian plant-derived materials were evaluated as solubility-enhancing excipients: yam starch (Dioscorea spp.) as a cyclodextrin alternative complexing agent, mucilage from Abelmoschus esculentus (okra) as a polymer matrix former, and Cola acuminata (kola nut) lipid fraction as a lipid-based drug delivery component. Target drugs were griseofulvin (BCS Class II) and ketoconazole (BCS Class II/IV). Excipient characterisation confirmed pharmaceutical-grade purity, functionality, and safety profiles. Solid dispersion and co-crystal formulations using okra mucilage achieved 4.7-fold and 3.2-fold dissolution enhancement for griseofulvin and ketoconazole respectively versus raw drug. Lipid-based formulations using Cola acuminata lipid fraction improved griseofulvin oral bioavailability 2.8-fold in rat models compared to commercial reference. Physicochemical stability under Zone IV ICH conditions was adequate for all lead formulations over 12 months. This study provides an original contribution to pharmaceutical technology using indigenous Nigerian excipients, demonstrating a scalable pathway for improving bioavailability of locally manufactured poorly soluble drugs.

Keywords: bioavailability enhancement, poorly water-soluble drugs, Nigerian natural excipients, solid dispersion, drug delivery