"Whole Chinese angelica" microemulsion: its preparation and in vivo and in vitro evaluations.

CONTEXT: The difference between the chemical polarities of the two categories of active chemical constituents in Chinese angelica volatile oil (CAVO) and Chinese angelica water extract (CAWE) greatly limit the development and clinical application of Chinese angelica preparation. OBJECT: The aim of this study is to design and prepare a "whole Chinese angelica" microemulsion (WCAM) that contains both CAVO and CAWE and at the same time to evaluate it in vivo and in vitro. MATERIALS AND METHODS: CAVO and CAWE extracted from Chinese angelica were used as the oil and aqueous phases, respectively, to prepare the WCAM; its physicochemical property was observed, and its drug potency and oral bioavailability were evaluated. RESULTS: The formula of the WCAM was optimized as Tween-80:ethanol:CAVO:CAWE = 3:3:1:40. The droplet size of the WCAM was 72.64 nm and the WCAM was proved to be physicochemically stable when it was kept at 0 °C, 4 °C, 25 °C and 40 °C for 3 months. The WCAM could markedly prolong blood clotting time, decrease whole blood viscosity and whole blood reduced viscosity at different shear rates, and improve hemorheological parameters. The results of the pharmacokinetic evaluation show that the AUC0-7 of the WCAM was 4510.66 and was about 4.41-fold compared to that of danggui concentrated pills (an existing Chinese angelica pharmaceutical preparation). CONCLUSION: It can be concluded, that the WCAM is a promising Chinese angelica preparation that has great prospects in the treatment of dysmenorrhea and irregular menstruation.

Preparation and evaluation of andrographolide-loaded microemulsion.

Andrographolide has a low aqueous solubility and oral bioavailability, which limits its clinical application. Reform the dosage forms of andrographolide to improve its aqueous solubility and oral bioavailability. The formulation, characterisation, stability, anti-inflammatory effect, pharmacokinetics and oral toxicity of andrographolide-loaded microemulsion, were studied. An formulation of O/W microemulsion consisting of an oil phase of isopropyl myristate, a surfactant phase of Tween 80, a co-surfactant of alcohol, and water was found to be ideal, with mean droplet size of 15.9 nm, a high capacity of solubilisation for andrographolide (8.02 mg mL(-1)). Such an andrographolide-loaded microemulsion is stable by monitoring the time, temperature and gravity-dependent change, and has a much better anti-inflammatory effect and a higher biological availability than andrographolide tablets. Besides, it also shows a very low acute oral toxicity. The andrographolide-loaded microemulsion is a promising dosage form of andrographolide.