Pharmacokinetics, tissue distribution and bioavailability of nitrendipine solid lipid nanoparticles after intravenous and intraduodenal administration

Purpose: The aim of this research was to study whether the bioavailability of nitrendipine (NDP) could be improved by administering nitrendipine solid lipid nanoparticles (SLN) duodenally to rats. Methods: Nitrendipine was incorporated into SLN prepared by hot homogenization followed by ultrasonication method. SLN were produced using various triglycerides (trimyristin, tripalmitin and tristearin), soy phosphatidylcholine 95%, poloxamer 188 and charge modifiers (dicetyl phosphate, DCP and stearylamine, SA). Particle size and charge measurements were made with a Malvern Zetasizer. Pharmacokinetics of nitrendipine SLNs (NDP-SLNs) after intravenous (i.v.) and intraduodenal (i.d.) administration to conscious male Wistar rats were studied. Tissue distribution studies of NDP-SLNs were carried out in Swiss albino mice after i.v. administration and compared to nitrendipine suspension (NDP-Susp). Results: Average size and zeta potential of SLNs of different lipids, with and without charge modifiers ranged from 101.9 +/- 3.0 to 123.5 +/- 3.0 nm and -35.1 +/- 0.5 to +34.6 +/- 2.3 mV, respectively. AUC((0-infinity)) was increased (up to 4.51-folds) and clearance was decreased (up to 4.54-folds) after i.v. administration of NDP-SLNs with and without charge modifiers compared to NDP-Susp. Effective bioavailability of NDP-SLNs were 2.81-5.35-folds greater after i.d. administration in comparison with that of NDP-Susp. In tested organs, the AUC and MRT of NDP-SLNs were higher than those of NDP-Susp especially in brain, heart and reticuloendothelial cells containing organs. Conclusions: SLN are suitable drug delivery systems for the improvement of bioavailability of nitrendipine. Negatively and positively charged SLN were better taken up by the liver and brain, respectively.