Enhanced oral bioavailability of Irbesartan via nano-bilosomes: A potential breakthrough in hypertension treatment

Irbesartan (IRB), a widely used antihypertensive medication, exhibits limited therapeutic efficacy due to poor solubility and stability characteristics, which compromise patient adherence. This investigation focused on developing and optimizing a nano bilosomal formulation of IRB to enhance oral bioavailability, extend release duration, and improve pharmacological performance. Through D-optimal design methodology, the study examined key formulation variables including bile salt concentration, cholesterol content, bile salt type, edge activator type, and soybean phosphatidylcholine to bile salt ratio (SPC). These parameters were evaluated against key performance indicators: particle size (PS), zeta potential (ZP), and encapsulation efficiency (EE%). Physicochemical characterization included DSC analysis, TEM imaging, and in vitro release studies. The optimized bilosomal formulation demonstrated favorable characteristics with a particle size of 109.99 nm, zeta potential of -30.999 mV, and encapsulation efficiency of 94.54 %. Physicochemical characterization confirmed the absence of IRB-excipient interactions, while DSC analysis revealed IRB amorphization. TEM imaging validated spherical morphology of the formulated structures. The IRB-loaded bilosomes exhibited sustained biphasic release over 24 h, achieving relative bioavailability 1.42-fold and 1.30-fold higher compared to IRB solution and commercial formulation, respectively. The nano bilosomal formulation significantly enhances IRB solubility, stability, and bioavailability, offering a promising approach for improved oral delivery and therapeutic outcomes. Additional research addressing scalability and clinical efficacy is warranted.