Formulation of Solid Lipid Nanoparticles of Cilnidipine for the Treatment of Hypertension

Cilinidipine is a fourth generation N and L-type calcium channel antagonists used alone or in combination with another drug to treat hypertension. Cilnidipine is poorly water -soluble, BCS class II drug with 6 to 30 percent oral bioavailability due to first pass metabolism. So to protect the drug from degradation and improve its dissolution, solid lipid nanoparticles were prepared. Glyceryl monostearate was selected as lipid while span 20: tween 20 were selected as surfactant blends. The formulations were evaluated for various parameters, as percent transmittance, drug content, percent encapsulation efficiency; percent drug loading, In vitro drug release and particle size. Optimized formulation was lyophilized using lactose as a cryo-protectant. The lyophilized formulation was evaluated for micromeritic properties, particle size and in vitro dissolution. It was further evaluated for DSC, XRD, and SEM. Percent encapsulation efficiency and percent drug loading of optimized formulation (F3) were 78.66percent and 9.44percent respectively. The particle size of F3 formulation without drug was 204 nm and with the drug was 214 nm. The particle size of the reconstituted SLN was 219 nm. In DSC study, no obvious peaks for cilnidipine were found in the SLN of cilnidipine indicated that the cilnidipine must be present in a molecularly dissolved state in SLN. In X-ray diffractometry absence of peaks representing crystals of cilnidipine in SLN indicated that the drug was in an amorphous or disordered crystalline phase in the lipid matrix. Thus, solid lipid nanoparticle formulation is a promising way to enhance the dissolution rate of cilnidipine. Keywords: Cilnidipine, Solid Lipid Nanoparticle, Hypertension