Background: Poorly water-soluble drugs do not dissolve well in aqueous-based gastrointestinal fluid; therefore, they are not well absorbed. Thus, employing a suitable solubility enhancing technique is necessary for such a drug. Drug/HP‑β‑CD complexation is a promising way to improve solubility and dissolution of a poorly water-soluble drug. Levodropropizine was used as a model drug in this study.
Objectives: The purpose of this research was to enhance the aqueous solubility and dissolution rate of levodropropizine by employing the inclusion complexation technique.
Material and methods: A microparticle formulation was prepared from levodropropizine and hydroxypropyl-β-cyclodextrin (HP‑β‑CD) in a 1:1 molar ratio through the spray-drying technique. The host-guest relationship between levodropropizine and HP‑β‑CD was also investigated using the molecular docking computational methodology. The aqueous solubility and dissolution rate of levodropropizine in formulations were assessed and compared with those of the drug alone. X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) were applied for the solid-state characterization of the prepared samples.
Results: According to the research outcomes, the levodropropizine/HP‑β‑CD formulation had enhanced the aqueous solubility (351.12 ±13.26 vs 92.76 ±5.00 mg/mL) and dissolution rate (97.83 ±3.36 vs 3.12 ±1.76% in 10 min) of levodropropizine, compared to the plain drug powder. The levodropropizine/ HP‑β‑CD formulation had converted the crystalline drug into its amorphous counterpart. Furthermore, no covalent interaction was found to exist between levodropropizine and HP‑β‑CD. The spray-dried particles were discrete. Each particle had a shriveled appearance.
Conclusions: The levodropropizine/HP‑β‑CD formulation is, therefore, recommended for the more effective administration of levodropropizine through the oral route.
Keywords: amorphous form; cyclodextrins; dissolution rate; phase solubility; spray-drying.