Solid Dispersion of Dolutegravir: Formulation Development, Characterization, and Pharmacokinetic Assessment

Abstract

A recently authorized antiviral drug called dolutegravir has solubility problems and could be a Biopharmaceutical Classification System (BCS) class II candidate. The current study aimed to improve dolutegravir’s solubility and efficiency by employing the solid dispersion method. Different ratios of hydrophilic polymeric carriers, including polyethylene glycol (PEG) 6000, polyvinyl pyrrolidone (PVP) (30K), and hydroxypropyl methylcellulose (HPMC), were used. Dolutegravir (DTG) and soluplus were produced as a solid dispersion at 1:5 ratio using the solvent evaporation method. A variety of techniques were utilized to describe the solid state, including powder X-ray diffraction (XRD), differential scanning calorimetry (DSC), and fourier transform infrared spectroscopy (FTIR). Produced solid dispersion did not reveal any physicochemical interactions between the DTG and soluplus, but the X-ray diffractogram clearly showed that the drug’s crystalline state had transformed to an amorphous state. DTG was released quickly from solid dispersion (92%) compared to pure drug (10.12%), physical mixture (22.06%), and commercially available DTG (62.90%). The formed solid dispersion’s drug release kinetics was in line with the Higuchi Model. Finally, the rapid drug release from the solid dispersion formulation showed higher Cmax (15.25 ± 0.40 μg/mL) compared to the physical mixture (5.11 ± 0.20 μg/mL) and pure drug (4.91 ± 0.73 μg/mL). DTG’s enhanced bioavailability in experimental wistar rats (AUC: 147.99 ± 23.86 μg/h/mL) further supported this when compared to the AUC of animals administered with physical mixture (52.35 ± 4.32 μg/h/mL) and pure drug (43.32 ± 3.13 μg/h/mL). Thus, it could be inferred that by employing the solid dispersion delivery system and the hydrophilic carrier, soluplus, the bioavailability and dissolution profile of DTG could both be improved, which could be expected to improve the drug’s effectiveness in treating Human immunodeficiency virus/Acquired immunodeficiency syndrome (HIV/AIDS).