liposomal and non-liposomal formulations of vitamin c: comparison of the antihypertensive and vascular modifying activity in renovascular hypertensive rats

Background: liposomes constitute a promising drug deliveryvehicle, and are believed to improve drugs’ effectiveness. this studywas aimed to compare antihypertensive and vascular modifyingactivities of liposomal and non-liposomal forms of ascorbic acid.methods: forty-nine male sprague-dawley rats were randomlydivided into seven groups (n=7): a sham vehicle-receiving(sham-veh), hypertensive (htn), vehicle-receiving hypertensive(htn-veh), two liposomal ascorbic acid-treated hypertensiveat 50 or 100 mg/kg/day (lvc-50 and lvc-100), and two nonliposomalascorbic acid-treated hypertensive at 50 or 100 mg/kg/day (vc-50 and vc-100). systolic blood pressure (sbp) and heartrate (hr) were measured weekly; after 4 weeks, dose-responsesto phenylephrine (pe) in the absence and presence of nitro-largininemethyl ester (l-name), acetylcholine (ach), and sodiumnitroprusside (snp) were obtained on aortic rings. data wereanalyzed with one-way anova and duncan’s multiple range testat a p value of <0.05 using sigmastat statistical software.results: compared to the non-liposomal form, the liposomalone was associated with more prominent effects on the final sbp.both forms of ascorbic acid decreased sbp dose-dependently.the basal and stimulated release of nitric oxide (no) wassignificantly recovered by both forms of ascorbic acid. thepe maximal responses were not significantly different betweenthe liposomal and non-liposomal groups (p=0.08). althoughthe emax of ach-relaxation response was not different in twopreparation forms, ach-relaxation response induced a lowerconcentration of the liposomal form of ascorbic acid (p=0.03)conclusion: the liposomal ascorbic acid exhibited relaxationactivity in significantly lower concentrations. the observedeffects were partly mediated by the increased basal release of no.