Formulation Optimization and Evaluation of Nanostructured Lipid Carriers Containing Valsartan
Nanostructured lipid carriers (NLCs), a lipid based colloidal carrier system, offer many advantages such as increase the solubility, improves the bioavailability and therapeutic efficacy. Incorporation of liquid lipid can improve the drug loading capacity in the NLCs. Valsartan is an antihypertensive drug with low oral bioavailability ranging from 10-35% because of poor solubility and extensive first pass hepatic metabolism. The purpose of present study was to develop and characterize the valsartan loaded nanostructured lipid carriers (Val-NLCs) to enhance the solubility, bypass the hepatic first-pass metabolism, and enhance the lymphatic absorption leading to greater oral bioavailability. Valsartan loaded NLCs were prepared by melt emulsification method and optimized using a two level full factorial design. Effect of content of Capmul MCM EP on crystallinity of tristearin was studied by differential scanning calorimetry (DSC) method. The particle size, entrapment efficiency, drug loading and zeta potential values of optimized batch were 62±0.494 nm, 86.59±0.671, 8.65±0.06 % and -17.4 mV, respectively. TEM images showed spherical particles with diameter of around 50 nm. In vitro drug release of 70% was observed at the end of 12 hrs. Ex-vivo drug release of 90% was observed in 2 hrs. Stability study indicated that the prepared Val-NLCs suspension was stable at refrigerator conditions for one month. Lyophilization produced free flowing Val-NLCs powder from suspension and was easy to reconstitute. Based on these results, it is concluded that NLCs are promising drug delivery for improving the oral bioavailability of valsartan.