Preparation, Characterization and In-Vitro Efficacy of Roflumilast Nanosuspension in Cigarette Smoke-Induced Chronic Obstructive Pulmonary Disease

Roflumilast (RFL) is a well-known drug employed for the treatment of asthma and COPD. However, the use of this drug is limited by poor solubility, low bioavailability, and side effects. The aim of this study was to overcome the solubility challenges by preparing roflumilast nanosuspension (RFL NSPs) and to study the effect of critical variables like polymer concentration, sonication time, and homogenizer cycles on the particle size, zeta potential and entrapment efficiency of the NSP. The optimized formulation batch showed a particle size of 203 nm with PDI of 0.620, zeta potential of -4.13mVand an entrapment efficiency of 77.19%, using10 mg of PVPK30, 30 min of sonication and 20 cycles of high-pressure homogenizer. The optimized formulation was characterized with DSC, FTIR, TEM, XRD, FESEM, stability studies, and in-vitro drug release experiments. The findings revealed improved solubility characteristics and the formulated NSP remained stable throughout the 90-day storage period as there was no variation in particle size, zeta potential, viscosity, and pH. Cigarette smoke extract (CSE)-induced in vitro COPD model in human bronchial epithelial cells (BCiNS1.1) was utilized. The RFL NSPs were assessed for in-vitro cytotoxicity study to find our maximum safe dose following by investigating key protein expression related to COPD. Human cytokine protein array was used to study the effect of RFL NSPs on inflammatory proteins, antioxidant related protein, and senescence-associated proteins. RFL NSPs significantly decreases Serpine-1 and Endoglin pnspnsrotein. RFL NSPs also reduce the levels of inflammatory proteins such as IL-8 (Interleukin-8), Osteopontin, MIP-1α/1β, VEGF (Vascular Endothelial Growth Factor) and the antioxidant-related gene Transferrin Receptor.