RESUMO
Objective: To prepare ligustrazine pamoate (Lig-PAM) sustained-release nanosuspension (Lig-PAM-NSps) and determine its in vitro release characteristics. Methods: Lig-PAM was prepared by hydrophobic salt formation method and its physicochemical properties were characterized. Then, Lig-PAM-NSps was prepared by miniaturized medium grinding method. The prescription and preparation process of Lig-PAM-NSps were optimized by the single factor and orthogonal experiment with average particle size, polydispersity index (PDI) and stability coefficient (SI) as indicators. Lig-PAM-NSps was characterized, and its stability and in vitro release was also investigated. Results: The compound ratio of Lig-PAM prepared by Lig and PAM in the amount of 1:1 was (97.48 ± 0.04)%. Compared with Lig, the solubilities of Lig-PAM in water and simulated body fluids were decreased by 95.50% and 77.39%, respectively. Fourier transform infrared spectroscopy (FT-IR) and X-ray powder diffraction (XRD) showed that the Lig and PAM formed Lig-PAM. The optimum prescription size of Lig-PAM-NSps was (585 ± 5) nm, PDI was (0.328 ± 0.015) and SI was (0.928 ± 0.012). The scanning electron microscopy (SEM) showed that Lig-PAM-NSps was spherical with uniform size distribution, and the particle size was about 600 nm and its physical stability was good within 60 d. The results of in vitro release showed that Lig-PAM-NSps had obvious sustained-release effect compared with Lig solution within 48 h, and showed the first-order release characteristics [ln(1-Q) = 0.153 67 t + 80.458 14, r = 0.998 26]. Conclusion: The preparation progress of Lig-PAM-NSps is stable and can release Lig slowly in vitro.
RESUMO
Based on the fact that glycyrrhizic acid can form micelles in aqueous solution and play a role in solubilization, the optimal compatibility ratio between puerarin and glycyrrhizic acid was screened to prepare puerarin-glycyrrhizic acid dispersible tablets and investigate the dissolution of puerarin. The particle size, Zate potential and puerarin dissolution were compared among the micellar solutions with mass ratio of 7∶1, 6∶1, 5∶1, 4∶1, 3∶1 and 2∶1(puerarin to glycyrrhizic acid), and it was found that when the mass ratio of puerarin and glycyrrhizic acid was 5∶1, the micelle showed smallest particle size, uniform distribution, and largest puerarin dissolution, so mass ratio of 5∶1 was determined as the optimal condition. The formulation of puerarin-glycyrrhizic acid dispersible tablets was optimized by single factor and orthogonal test: puerarin 100.0 mg, glycyrrhizin 20.0 mg, polyvinylpolypyrrolidone 24.0 mg as disintegrating agent, microcrystalline cellulose 135.0 mg as stuffing bulking agent, hydroxypropyl methyl cellulose 18.0 mg as adhesive agent, magnesium stearate 2.7 mg as lubricant, and tablet weight of 300.0 mg. High-performance liquid chromatography(HPLC) method was used to determine the content of puerarin in dispersible tablets. Puerarin showed a good linear relationship(r=0.999 8) in the range of 15.5-248 g·L~(-1), with high precision(RSD<2.0%) and good repeatability(RSD<2.0%), and the recovery rate was 101.1%, RSD 0.89%. There was no significant difference in the quantity of puerarin in different batches of puerarin-glycyrrhizic acid dispersible tablets. When the artificial gastric juice was used as the dissolution medium, the dissolution of puerarin in puerarin-glycyrrhizic acid dispersible tablets could reach over 85% within 15 min. When phosphate buffer(pH 6.8) was used as the dissolution medium, the dissolution of puerarin in the puerarin-glycyrrhizic acid dispersible tablets had a faster dissolution rate in vitro, 99.8% in 30 min. Therefore, puerarin-glycyrrhizic acid dispersible tablets could improve the dissolution of puerarin in vitro due to the solubilization effect of glycyrrhizic acid.