Novel mixed hydrotropic solubilization of Zaleplon: Formulation of oral tablets and in-vivo neuropharmacological characterization by monitoring plasma GABA level

Zaleplon (ZP) is a poorly water-soluble non-benzodiazepine hypnotic drug indicated for the short-term treatment of insomnia having a bioavailability of about 30%. The aim of the present study is to enhance the solubility and consequently the bioavailability of ZP using hydrotropic agents (HA). The solubility of ZP increased about 350- and 2000-fold, respectively, when 1 M of sodium benzoate and resorcinol were used as hydrotropic agents. The optimized mixed hydrotropic tablet formula (F5) composed of Resorcinol:Sodium benzoate microparticles prepared by solvent evaporation technique in a ratio of 4:1 w/w exhibits a significantly higher (p < 0.05) in-vitro dissolution (Q5 min) of 31.7 ± 0.11% after five minutes (Q5min) compared to 10.0 ± 0.10% for Sleep aid (5 mg) respectively. The optimized formula (F5) showed significantly higher (p < 0.05) GABA concentration of 122.5 ± 5.5 mg/mL in plasma compared to 118 ± 1.00 and 27.8 ± 1.5 mg/mL for Sleep aid (5 mg) and control taking only saline respectively suggesting a higher neuropharmacological effect of ZP following hydrotropic solubilization.

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