Bioavailability enhancement of ondansetron after nasal administration of Caesalpinia pulcherrima-based microspheres

CONTEXT: Natural polymers have attracted a great deal of attention for use as potential carriers in site-specific delivery over past decades. Mucoadhesive microspheres are useful tools for nasal drug delivery. OBJECTIVES: To prepare and evaluate mucoadhesive microspheres as mode for nasal delivery of ondansetron using Caesalpinia pulcherrima galactomannan (CPG). MATERIALS AND METHODS: Conventional spray-dried CPG nasal microspheres loaded with ondansetron for intranasal drug delivery in order to avoid the first pass metabolism with improved therapeutic efficiency in treatment of nausea and vomiting as an alternative therapy to parenterals. Developed microspheres were evaluated for characteristics like particle size, entrapment efficiency, zeta potential, swelling ability, in-vitro mucoadhesion, in-vitro drug release, DSC, XRD study and histopathological evaluation of tissue. CPG-based ondansetron microspheres were studied in rabbits for screening nasal absorption potential of nasal formulation. RESULTS: Developed nasal microspheres possess entrapment efficiency of 80-89%, higher mucoadhesion of 72-84% across goat nasal mucosa. In-vivo study showed that microspheres based on mucoadhesive polymer were able to promote quick drug absorption as well as enhanced bioavailability of drug. DISCUSSION: Histopathological studies evaluated biocompatible and nontoxic nature of CPG in nasal cavity. Developed mucoadhesive microspheres by nasal route showed enhancement of bioavailability as compared to oral route in rabbits. CONCLUSION: CPG-based mucoadhesive microspheres can successfully deliver ondansetron intranasally, sustain its effect, avoid first pass effect, an alternative route of administration to injection and thus enhance systemic bioavailability of ondansetron hydrochloride.