Formulation of Quinine Suppository and Evaluation of Quinine uptake in the Mouse Brain.
A Thesis Submitted to the School of Postgraduate Studies, University of Lagos
The occurrence of resistance to chloroquine and sulfadoxine/pyrimethamine by Plasmodium falciparum stimulated new interest in quinine for treating multi-resistant falciparum infection. Parenteral quinine is the gold treatment in the management of severe and complicated malaria. There is the need for early initiation of treatment in management of complicated malaria. An antimalarial drug to be used at home must be safe, effective, affordable and easy to administer A rectal formulation of quinine will serve the purpose of home initiation of treatment. The main objective of this work was to develop a stable quinine suppository that will ensure adequate release of quinine and evaluate quinine uptake into the four sections of the mouse brain Cocoa butter and Fattibase TM were used in the preparation of suppositories containing 200mg quinine bisulphate. The release profiles of the formulations with varying concentrations of polysorbate 80 (0, 1, 2 and 5%) were evaluated by in-vitro dissolution in pH 8 buffer medium. Evaluation of brain uptake was carried out in various stages using the murine mice model. Quantification of uptake into the four brain sections was done with a High Pressure Liquid Chromatography technique. Uptake was compared in the four brain sections of parasitized and non-parasitized murine mice as a function of time (30, 60, 120, 180, 240 min). Quinine uptake from suppository was also compared with uptake from peritoneal injection in parasitized and non-parasitized. The values obtained were subjected to statistical analysis using the 3-way ANOVA. The Formulations of suppositories in cocoa butter and FattibaseTM released quinine in adequate quantity. Addition of polysorbate 80 improved release of quinine significantly (P = 0.005 for cocoa butter and P = 0.003 for FattibaseTM). Cocoa butter with 1% Polysorbate 80 released 36.8% quinine bisulphate in 60 min while release from suppositories with 2% and 5% surfactant was erratic. FattibaseTM suppositories with 5% polysorbate 80 released 85% quinine content in 60min. This formulation was stable in the refrigerator for three months while samples stored at ambient temperature were stable for one month. From the release profiles, three formulations have very high potentials in management of cerebral malaria: cocoa butter+1%, FattibaseTM + 2% and 5% respectively. Fluorescence microscopy revealed green fluorescence characteristic of quinine in the brain sections of parasitized and non-parasitized mice treated with quinine. Quinine crossed the blood brain barrier into the brain in parasitized and non-parasitized mice. This confirms that inflammation is not required for the transport of quinine bisulphate into brain. Quinine from the suppository was available in the brain in 30 min. Uptake had a significant time–dependence (P=0.000). Uptake in parasitized mice was significantly higher than that in the non-parasitized mice (0.000). Quinine uptake varied significantly in the four brain sections with olfactory lobe recording the highest uptake in the two groups of mice (0.000). Quinine uptake in the parasitized mice is biphasic while a steady decline was observed in non-parasitized mice over the time period. The concentration of quinine taken up by other brain sections: cerebrum, cerebellum and medulla oblongata was significantly lower than the concentration in the olfactory lobe with cerebrum having the lowest uptake in the parasitized mice. This intra-rectal formulation will be useful in pre-referral management procedures in primary health facilities, homes and rural areas.