[Optimization of extraction process for classic prescription Yihuang Decoction based on Box-Behnken design-response surface methodology, standard relation, and analytic hierarchy process combined with entropy weight method].

Based on the concept of quality by design(QbD), the Box-Behnken design-response surface methodology combined with standard relation(SR) and analytic hierarchy process(AHP)-entropy weight method(EWM) was applied to optimize the extraction process of the classic prescription Yihuang Decoction. The content of geniposidic acid, phellodendrine hydrochloride, and berberine hydrochloride in Yihuang Decoction, the extract yield, and fingerprint similarity were used as the critical quality attributes(CQAs) of the extraction process. The extraction time, water addition, and extraction times were used as the critical process parameters(CPPs). After determining the levels of each factor and level through single-factor experiments, response surface experiments were designed according to the Box-Behnken principle, and the experimental results were analyzed. The SR between each sample and the reference sample under various evaluation indicators of different extraction parameters was calculated. The weights of the five evaluation indicators were determined using AHP-EWM, followed by comprehensive evaluation. A function model between CPPs and CQAs characterized by comprehensive scores was established to predict the optimal extraction process parameters. In the final comprehensive weight coefficients, the yield rate accounted for 43.1%, and the content of berberine hydrochloride, phellodendrine hydrochloride, and geniposidic acid accounted for 35.1%, 6.3%, and 15.5%, respectively. After comprehensive score analysis with SR, the established second-order polynomial model was statistically significant(P<0.01, and the lack of fit was not significant). The predicted optimal extraction conditions for Yihuang Decoction were determined as follows: 8-fold volume of water, extraction time of 1.5 h, and extraction once. The mean comprehensive score of the validation experiment was 85.77, with an RSD of 0.99%, and it met the quality control stan-dards for the reference sample of Yihuang Decoction. The results indicate that the optimized extraction process for Yihuang Decoction is stable and reliable, and the water extract is close in quality attributes to the reference sample. This can serve as a foundation for the research and development of granules in the future. Box-Behnken design-response surface methodology combined with SR and AHP-EWM can provide references for the modern extraction process research of other classic prescriptions.

Study of the permeation-promoting effect and mechanism of solid microneedles on different properties of drugs.

In transdermal drug delivery systems, the physicochemical properties of the drug affect its percutaneous permeability. However, whether the physicochemical properties of drugs change their transdermal permeability in the presence of pores in the presence of solid microneedles (MNs) has been less studied in this area. In this project, cinnamaldehyde, curcumin, ferulic acid and geniposide were selected as model drugs for the study of their transdermal permeability under the action of MNs, and a combination of classical experiments and visualization means such as scanning electron microscopy and laser confocal was used to investigate the permeation-promoting mechanism of MNs. The results showed that the MNs had significant permeation-promoting effects on different properties of drugs, with the permeation-promoting effects on cinnamaldehyde, curcumin, ferulic acid and geniposide being 6.36, 17.43, 29.54 and 8.91 times, respectively, and the permeation-promoting effects were more pronounced for lipid-soluble and amphiphilic drugs. Using scanning electron microscopy, transmission electron microscopy and other means to confirm that MNs can promote the penetration by acting on the skin to produce pores, and their effect on skin structure is greater than that of drugs. In addition, the existence of pores increases the amount of drug transdermal, which may enhance the diffusion of drug on the skin, and has no effect on lipid exchange and transdermal route. Through the research, it has been found that MNs is equivalent to direct peeling of the stratum corneum (SC), but it is simpler and safer for the patient.