Pyridoxine Hydrochloride

Pyridoxine hydrochloride was administered intraperitoneally to rats at doses of 4 and 10 mg/kg/day for 20 days to evaluate its effects on lipid peroxidation and levels of 5-hydroxytryptophan and serotonin. Pyridoxine is a water-soluble vitamin required for amino acid metabolism and biosynthesis of neurotransmitters including GABA, dopamine and serotonin, with the latter dependent on decarboxylation of 5-hydroxytryptophan. Treatment with pyridoxine significantly increased levels of 5-HTP in all vitamin-treated groups compared to controls, and serotonin levels increased partially only in groups receiving pyridoxine with or without butylated hydroxytoluene.
The findings suggest that pyridoxine plays a role in tryptophan metabolism by increasing production of 5-HTP, the immediate precursor of serotonin. The study also examined the relationship between pyridoxine and lipid peroxidation, with the vitamin demonstrating effects on oxidative stress markers. These results provide in vivo evidence that pyridoxine hydrochloride influences neurotransmitter precursor synthesis through its coenzyme functions in amino acid metabolism.

Fig. 1 Lipid peroxidation in young rat brains treated with pyridoxine and butylated hydroxytoluene. (Calderón-Guzmán D.; et al. 2004)

Doxylamine succinate and pyridoxine hydrochloride dual-loaded bilosomes were developed using phospholipid, sodium cholate and cholesterol via thin-film hydration method optimized by Box-Behnken design. The optimal bilosomes exhibited vesicle size of 243.23 nm, zeta potential of -31.33 mV, entrapment efficiency of 59.18% and 41.63% for doxylamine and pyridoxine, respectively. The bilosomes were incorporated into a thermally-triggered in situ gelling base for intranasal delivery. Pharmacokinetic studies in rats revealed a 1.7- to 3.73-fold increase in relative bioavailability of pyridoxine compared to intranasal free in situ gel and oral solution, with significantly extended mean residence time for both drugs. This bilosomal nanoplatform offers a promising intranasal delivery strategy for enhanced pharmacokinetics and tolerability.

Fig. 2 Characterization of pyridoxine hydrochloride-loaded bilosomes. (Salem H F.; et al. 2022)