Pioglitazone-loaded nanostructured lipid carriers: In-vitro and in-vivo evaluation for improved bioavailability

Pioglitazone (PZ), a highly lipophilic Class II drug with poor aqueous solubility possesses low oral bioavailability. The oral bioavailability of pioglitazone can be improved by incorporating into nanostructured lipid carriers (NLCs). Pioglitazone-loaded nanostructured lipid carriers (PZ-loaded NLCs) were developed by using the solvent emulsification evaporation method. The lipid phase of the formulation consists of a solid and liquid lipid mixture (fatty acids and oils) and surfactants (Tween 20, Span 40) were used for the stability of the formulation. PZ-loaded NLCs were characterized for physicochemical characteristics including particle size, zeta potential, polydispersity index (PDI), fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM) and stability studies. Moreover, drug entrapment efficiency, drug loading capacity, drug release, toxicity studies, permeation studies, and in-vivo studies were performed to evaluate enhanced bioavailability. PZ-loaded NLCs have shown an average particle size of 152 nm, PDI of 0.19, and a negative value of zeta potential. Drug entrapment efficiency and loading capacity were about 83% and 5.8%, respectively. SEM results delineated the smooth homogenous surface in nano-sized range, whereas FTIR spectra demonstrated no interaction between components of PZ-loaded NLCs formulation. For drug release studies, the dialysis bag method confirmed a biphasic release behavior in beginning followed by slow, controlled release up to 24 h. Furthermore, permeation studies showed enhanced permeability and in-vivo studies confirmed the enhanced bioavailability of pioglitazone. Based on the above finding, it can be concluded that NLCs are a versatile tools for enhancing the bioavailability of poorly soluble Class II drugs.