Spanlastics as a Potential Platform for Enhancing the Brain Delivery of Flibanserin: In Vitro Response-Surface Optimization and In Vivo Pharmacokinetics Assessment

Flibanserin was licensed by the United States Food and Drug Administration (FDA) as an oral non-hormonal therapy for pre-menopausal women with inhibited sexual desire disorder. However, it suffers from susceptibility to first-pass metabolism in the liver, low aqueous solubility, and degradation in the acidic stomach environment. Such hurdles result in a limited oral bioavailability of 33%. Thus, the aim of the study was to utilize the principles of nanotechnology and the benefits of an intranasal route of administration to develop a formulation that could bypass these drawbacks. A response-surface randomized D-optimal strategy was used for the formulation of flibanserin spanlastics (SPLs) with reduced size and increased absolute zeta potential. Two numerical factors were studied, namely the Span 60: edge activator ratio (w/w) and sonication time (min), in addition to one categorical factor that deals with the type of edge activator. Particle size (nm) and zeta potential (mV) were studied as responses. A mathematical optimization method was implemented for predicting the optimized levels of the variables. The optimized formulation was prepared using a Span: sodium deoxycholate ratio of 8:2 w/w; a sonication time of 5 min showed particle sizes of 129.70 nm and a zeta potential of -33.17 mV. Further in vivo assessment following intranasal administration in rats showed boosted plasma and brain levels, with 2.11- and 2.23-fold increases (respectively) compared to raw FLB. The aforementioned results imply that the proposed spanlastics could be regarded as efficient drug carriers for the trans-nasal delivery of drugs to the brain.

Automated summary

This study aimed to develop an intranasal formulation of flibanserin using nanotechnology to overcome the limitations of oral administration. The optimized formulation showed improved bioavailability and brain delivery compared to the raw drug.