Harnessing of Doxylamine Succinate/Pyridoxine Hydrochloride-Dual Laden Bilosomes as a Novel Combinatorial Nanoparadigm for Intranasal Delivery: In Vitro Optimization and In Vivo Pharmacokinetic Appraisal.

The present work is concerned with tailoring and appraisal of a novel nano-cargo; bilosomes (BLS) dual laded with doxylamine succinate (DAS) and pyridoxine hydrochloride (PDH), the first treatment option against gestational nausea and vomiting, for intranasal delivery. This bifunctional horizon could surmount constraints of orally-commercialized platforms both in dosage regimen and pharmacokinetic profile. For accomplishing this purpose, DAS/PDH-BLS were elaborated integrating phospholipid, sodium cholate and cholesterol applying thin-film hydration method based on Box-Behnken design. Utilizing Design-Expert® software, the effect of formulation variables on BLS physicochemical features alongside the optimal formulation selection were investigated. Then, the optimum DAS/PDH-BLS formulation was incorporated into a thermally-triggered in situ gelling base. The in vivo pharmacokinetic studies were explored in rats for intranasal DAS/PDH-BLS in situ gel compared with analogous intranasal free in situ gel and oral solution. The optimized BLS disclosed vesicle size of 243.23 nm, ζ potential of -31.33 mV, entrapment efficiency of 59.18 and 41.63%, accumulative % release within 8 h of 63.30 and 85.52% and accumulative permeated amount over 24 h of 347.92 and 195.4 µg/cm2 for DAS/PDH, respectively. Following intranasal administration of the inspected BLS in situ gel, pharmacokinetic studies revealed a 1.64- and 2.3-fold increment in the relative bioavailability of DAS and a 1.7- and 3.73-fold increase for PDH compared to the intranasal free in situ gel and oral solution, respectively besides significantly extended mean residence times for both drugs. Thus, the intranasally exploited DAS/PDH-BLS could be deemed as a promising hybrid nanoplatform with fruitful pharmacokinetics and tolerability traits.