Formulation, characterization and and evaluation of aloe-emodin-loaded solid dispersions for dissolution enhancement.

Objective: To prepare aloe-emodin solid dispersion (AE-SD) and determine the metabolic process of AE and AE-SD in vivo.

Methods: AE-SD was prepared viasolvent evaporation or solvent melting using PEG-6000 and PVP-K30 as carriers. Thermogravimetric analysis, X-ray diffraction spectroscopy, differential scanning calorimetry, Fourier transform infrared spectroscopy and scanning electron microscopy were used to identify the physical state of AE-SD. Optimal prescriptions were screened viathe dissolution degree determination method. Using Phoenix software, AE suspension and AE-SD were subjected to a pharmacokinetic comparison study analyzing the alteration of behavior in vivo after AE was prepared as a solid dispersion. Acute toxicity was assessed in mice, and the physiological toxicity was used as the determination criterion for toxicity.

Results: AE-SD showed that AE existed in the carrier in an amorphous state. Compared with polyethylene glycol, polyvinylpyrrolidone (PVP) inhibited AE crystallization, causing the drug to transform from a dense crystalline state to an amorphous form and increasing the degree of drug dispersion. Therefore, it was more suitable as a carrier material for AE-SD. The addition of poloxamer (POL) was more beneficial to the stability of solid dispersions and could reduce the amount of PVP. The dissolution test confirmed that the optimal ratio of AE to the composite vector AE-PVP-POL was 1：2：2, and its dissolution effect was also optimal. Based on the pharmacokinetic comparison, the drug absorption was faster and quickly reached the peak of blood drug concentration in AE-SD compared to AE, the Cmax of AE-SD was greater than that of AE, and t1/2 and mean residence time of AE-SD were less than AE. The results showed that the drug metabolism in AE-SD was better, and the residence time was shorter. The toxicology study showed that both AE and AE-SD had no toxicity.

Conclusion: This paper established that the solubility of the drug could be increased after preparing a solid dispersion, as demonstrated by in vitro dissolution experiments. In vivo pharmacokinetics studies confirmed that AE-SD could improve the bioavailability of AE in vivo, providing a new concept for the research and development of AE preparations.