Formulation, Characterization, Optimization, and Pharmacokinetic Evaluation of Cilnidipine-Loaded Liquisolid Compacts with Improved Dissolution and Bioavailability

Purpose Cilnidipine (BCS class II drug) is a calcium channel blocker used in the treatment of hypertension. Poor water solubility, unreliable oral absorption, and poor bioavailability make it a probable candidate for designing novel drug delivery. The objective of the present investigation was to formulate, optimize, and study in vitro and in vivo performance of cilnidipine-loaded liquisolid compacts. Methods Solid-state characterization was performed by FTIR, DSC, SEM, and XRD. Preliminary screening was performed to select non-volatile solvent, carrier, and coating material based on flowable liquid retention potential. Liquisolid compacts were optimized using 3 2 factorial designs and were studied for pre- and post-compression parameters, in vitro dissolution, dissolution validation, and pharmacokinetic and stability studies, whereas bioanalysis was carried out using HPLC–MS/Ms method. Results In the preformulation study, Transcutol HP was selected as the non-volatile solvent, and Neusilin US2 and Cab-o-sil were selected as the carrier and coating material, respectively, exhibiting compatibility with the drug. Liquisolid compacts were found to be compressible with the selected composition. In vitro studies indicated increased dissolution behaviour, whereas in vivo studies demonstrated improved bioavailability compared to the pure drug and marketed formulation. Conclusion In conclusion, formulated liquisolid compacts demonstrated increased dissolution and bioavailability making the formulation suitable for oral administration.