Morphological and microscopical identification of Genkwa Ramulus and its adulterants / 中国中药杂志

The purpose of this article is to identify Daphne genkwa and its adulterants, Wikstroemia chamaedaphne, according to the morphological and microstructure characteristics of their stem and foliage. The root of D.genkwa was studied simultaneously. The results indicated that the crude drug and processed pieces of Genkwa Ramulus were mainly composed of stems and branches where obvious opposite petiole scars and branch marks were able to be seen on their nodes. Otherwise, foliage or peduncles generally couldn't be found. Moreover, the fine silver flocculent fibers could be observed in the bark of fracture surface. The adulterants were the plant segments which were composed of stems, foliage and peduncles with spikelet-pedicel scars. There existed microstructures differences between Genkwa Ramulus and its adulterants. In the former, single thick lignified phloem fibers were interspersed in the stem phloem of the transverse section with very thick wall and unicellular non-glandular hairs could be observed on the lower epidermis of foliage. Nevertheless, in the latter, there was no thick lignified phloem fibers in cross section of stem phloem, the outer wall of epidermal cells of foliage hadthick cuticles and no non-glandular hairs in lower epidermis of foliage. The results can be used for the identification and the quality standard of the crude drug and processed pieces of D.genkwa.The characteristics of the microstructures and the transverse section can be used to identify the radix D.genkwa.

Limited sampling strategy models for estimating AUC for amlodipine in Chinese healthy volunteers / 药学学报

This study aims to save cost of sampling for estimating the area under the amlodipine plasma concentration versus time curve in 24 hours (AUC(0-24 h)). Limited sampling strategy (LSS) models was developed and validated by mutiple regression model within 4 or fewer amlodipine concentration values. Absolute prediction error (APE), root of mean square error (RMSE) and visual predict check were used as criterion. The results of Jackknife validation showed that fifteen (9.4%) of the 160 LSS based on regression analysis were not within an APE of 15% by using one concentration-time point. 156 (97.5%), 159 (99.4%) and 160 (100%) of the 160 LSS model were capable of predicting within an APE 15% by using 2, 3, 4 points, separately. Limited sampling strategies have been developed and validated for estimating AUC(0-24 h) of amlodipine. The present study indicated that the implemention of both 5 mg and 10 mg dosage could enable accurate predictions of AUC(0-24 h) by the same LSS model. This study shows that 12, 4, 24, 2 h after administration are key sampling time points. The combination of (12, 4), (12, 4, 24) or (12, 4, 24, 2 h) might be chosen as sampling hours for predicting AUC(0-24 h) in practical application according to requirement.