Development and characterization of bilastine nanosuspension for enhanced dissolution in orodispersible films

Bilastine, a second-generation antihistamine, is commonly prescribed for managing allergic rhinoconjunctivitis and urticaria due to its prolonged action. However, its therapeutic potential is constrained by poor water solubility and low oral bioavailability. This study aimed to enhance bilastine dissolution and patient compliance by formulating a nanosuspension-based orodispersible film (ODF). An anti-solvent precipitation method was employed to produce nanosuspension using different hydrophilic stabilizers (Soluplus®, Poloxamer 188, and PEG 6000). The influence of formulation parameters, such as the stabilizer ratio, the anti-solvent ratio, stirring speed, and the stabilizer type, on particle size and polydispersity index (PDI) was optimized using an experimental design approach. The optimal formulation, with a 1:1 stabilizer-to-drug ratio using Soluplus®, a 6:1 anti-solvent to solvent ratio, and a stirring rate of 820 rpm, yielded nanoparticles with a mean particle size of 83.8 nm and a narrow PDI of 0.019. This formulation also significantly enhanced the drug's dissolution rate in phosphate buffer pH 6.8, releasing 92.02% of bilastine within 90 minutes. Further characterization of the lyophilized nanoparticles using FESEM, FTIR, and XRD, confirmed their amorphous nature and drug compatibility. The optimized nanosuspension was subsequently incorporated into ODFs via the solvent-casting technique, with the optimal film formulated with a 1:1 ratio of PVA and HPMC E5 as the film-forming polymers, demonstrating a rapid disintegration time of 18 seconds and releasing 93.16% of bilastine within 6 minutes. These results confirm the successful formulation of bilastine into ODFs, significantly improving its dissolution compared to the pure drug.