Box–Behnken based furosemide-nanostructured lipid carriers (NLCs) delivery system for improving oral bioavailability

Objective: The fabrication of furosemide (FSM) with enhanced oral bioavailability and encapsulation was achieved using a nanostructured lipid carriers (NLCs) drug delivery system. Significance: The uniform drug distribution is a barrier due to its low dose. The lipid-based delivery system was selected based on its poor solubility and permeability, limiting its poor partitioning and solubility in water-based polymeric delivery systems. The lipophilicity of the FSM makes it favorable to partition with triglyceride-based Compritol 888 ATO and oleic acid with minimized drug expulsion, high drug payload, and sustained release over extended time frames. Methods: The Organic and aqueous phases of the microemulsion were stabilized using Tween 80, a hydrophilic surfactant. Box-Behnken design-based optimization was done using alteration in various formulation variables to obtain nano-formulation with the lowest particle size and polydispersity, maximal zeta potential and entrapment efficiency. Results: Design-Expert yielded several optimized formulations with the desirability function. Maximum desirability was obtained at a particle size of around 178 nm, a surface charge of −19.6 mV, and an EE of above 85%. The in vitro release profile depicted 86.5% of cumulative release after 24 h whereas, in vivo pharmacokinetic study revealed an increase in C_max from 0.48 µg/mL (FSM-Suspension) to 0.77 µg/mL (FSM NLCs) to increase the bioavailability to approx. 241% in FSM NLCs. The half-life escalation demonstrated that the residence time of the nanoparticles prolonged at the physiologic pH. Conclusions: FSM-NLCs exhibited sustained release over a prolonged period, improved residence time in the body, and their action was prolonged.