Tailoring cilnidipine nanostructured lipid carriers loaded transdermal patch for the treatment of hypertension: optimization, ex vivo and in vivo studies

The current investigation aimed to develop nanostructured lipid carriers (NLCs) as a potential transdermal drug delivery system for the improvement of cilnidipine (CIL) bioavailability. The high-pressure homogenization (HPH) method was utilized for the formulation of NLCs. Box-Behnken Design (BBD) was utilized to optimize CIL NLCs for entrapment efficiency, particle size and zeta potential. The resultant NLCs had a mean particle size of 98.2 +/- 05.08 nm, a zeta potential of -16.1 +/- 2.05 mV and an entrapment efficiency of 92.51 +/- 4.18%. Transmission electron microscopy (TEM) revealed spherical or elongated particles for CIL-NLCs. The optimized NLCs were embedded in the transdermal patch and were formulated utilizing the solvent casting method and investigated for CIL content, physical characteristics, skin permeation and in vivo pharmacokinetics study. In vivo pharmacokinetics experiments with an NLCs-embedded transdermal patch show, an increase in Cmax and Tmax, 1305.66 +/- 7.96 ng/mL and 4 h, respectively, when compared to the oral CIL dose. The flux values for ex vivo permeation studies for the CIL NLCs patch were determined to be 82.54 +/- 4.80 mu g/cm2/h. The bioavailability of CIL-loaded NLCs transdermal patch was found to be 2.9-fold greater than that of oral drug suspension, thus confirming the improvement of bioavailability of CIL by NLCs loaded transdermal patch.