Solid Dispersion of Usnic acid–HPMC 2910 Prepared by Spray drying and Freeze drying Techniques

Abstract

Usnic acid is a dibenzofuran derivate produced by some lichens species primarily Usnea sp., that has several pharmacological activities. Based on Biopharmaceutical Classification System (BCS), usnic acid belongs to class II that has high permeability but low solubility. Therefore, the purpose of this research was to increase the solubility of usnic acid by preparing solid dispersions (SD) using hydrophilic polymer HPMC 2910. Usnic acid and HPMC at ratio 1:1 (w/w) were prepared for solid dispersion using spray drying and freeze drying techniques. Physical mixture at the same ratio was prepared as comparison. Characterization for intact materials, physical mixture and solid dispersions were done using powder X-ray diffraction (PXRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), fourier transform infra-red (FT IR) spectroscopy, and solubility test. The result of PXRD showed a decrease of peak intensity for solid dispersions. Thermal properties of solid dispersions showed lower melting point compared to usnic acid and physical mixture. The morphology of solid dispersion depicted different shape compared to intact materials and physical mixture. The infra-red spectrum showed the slightly shift at wave numbers of functional groups but there was no new functional groups formed. The solubility of solid dispersions significantly increased, which the solubility test result were 55±0.023, 227±0.034, 567± 0.020, and 932±0.053 (μg/ml) for intact usnic acid, physical mixture, SD by spray drying and SD by freeze drying, respectively. In conclusion, solid dispersions of usnic acid – HPMC 2910 were able to modify physicochemical properties and increased the solubility.

Bactericidal Activity of Usnic Acid-Chitosan Nanoparticles against Persister Cells of Biofilm-Forming Pathogenic Bacteria

“…The XRD spectra showed several sharp characteristics as well as diffuse peaks in the diffraction pattern of the UA-CS NPs ( Figure 3B (Figure 3B, a). Similar peaks in UA has also been reported previously [46,47], which are also present in the UA-CS NPs ( Figure 3B, b). In case of CS NPs, an intense diffraction peak at 2 θ = 22.6 • has been observed ( Figure 3B, c) which is also present in the UA-CS NPs spectra along with some characteristic peaks of UA.…”

Solid Dispersion of Usnic Acid-PVP K30 and Evaluation of Antioxidant Activity

“…Among the methods mentioned above, solid dispersion is one the most popular methods to modify the psychochemical property active ingredient by dispersing the drug in either sugar, hydrophilic polymer or surfactant 9 . Our previous study has elaborated preparation and characterization of usnic acid in HPMC 10 . The aims of this study were to prepare solid dispersion of usnic acid by two different methods, spray and freeze-drying using PVP K-30, in order to increase its solubility and to evaluate the antioxidant activity.…”

Solid Dispersion as a Technical Solution to Boost the Dissolution Rate and Bioavailability of Poorly Water-Soluble Drugs

“…The applied negative pressure to the solution -usually containing water-is responsible for the subsequent sublimation process. 74 The lyophilization process can be employed using spray freeze-drying 75 or ultra-rapid freezing. 76,77 The lyophilization speed and maintaining the temperature under Tg of the ingredients during sublimation have a pivotal role in controlling the phase separation.…”