Unconventional Passive Enhancement of Transdermal Drug Delivery: toward a Mechanistic Understanding of Penetration Enhancers Releasing from Acrylic Pressure-Sensitive Adhesive of Patches.

PURPOSE: Penetration enhancers (PEs) enhancing efficacy depends on two processes: PEs release from patches and action on skin. Compared with their action on skin, PEs release process was poorly understood. Therefore, the purpose of this study was to make a mechanistic understanding of PEs release from acrylic pressure-sensitive adhesive of patches and propose an unconventional enhancement of PEs efficacy. METHODS: PEs efficacy was evaluated both in drug permeation study and drug pharmacokinetic study. Confocal Raman spectroscopy was employed to observe PEs release behavior by mapping PEs dynamic distribution in skin. The mechanism of PEs release behavior was provided from molecular interaction and rheology using FT-IR, molecular docking, molecular dynamic simulation and rheometer, separately. RESULTS: The release behavior of PEs themselves greatly restricted their efficacy. By using PEG 400, an improvement of oleic acid (OA) release behavior was achieved, and the efficacy of OA was significantly enhanced with enhancing ratio (ER) from 2.69 to 4.10 and AUClast from 1574 ± 87 to 2664 ± 249 ng·h/mL, separately. The improvement of OA release behavior was primarily resulted from reduction of the interaction between OA and adhesive, which was caused by other small molecules with a strong ability in forming hydrogen bonds with adhesive. Also, the rigidity of adhesive was a factor in affecting PEs release behavior. CONCLUSIONS: An unconventional passive enhancement of transdermal drug delivery was achieved via improving PEs themselves releasing from acrylic pressure-sensitive adhesive. Graphical abstract Influence of PEs release behavior on drug permeation through skin and molecular mechanism.

[Habitat areas extracting of Poria cocos in Anhui based on "3S" technologies].

"Adversity" is one primary element that impacts the pharmacology components of authentic Chinese herbal medicine. Knowledge about "adversity" is a precondition of yield estimation, quality monitoring, location selection and the geo-herbalism protection. Used 3S(GIS, RS and GPS) technology to combine multi-source key ecological factors of "Anling", and used parasitic relationships between organisms to extracting its suitable region for the first time. Results showed that the "Anling" were mainly distributed in Dabie coteau. Suitable area amount to 36.8 km², Yuexi, Shucheng, Jinzhai and Qianshan which account for about 93.55% of whole congenial region. The first three accounts for about 80.82%. It was Yuexi that account for 1/3 above especially. Field investigation verify accuracy of extraction about 91.67%, which has confirmed it is feasible that using the relationship between parasitic host and parasitic to extract native environment of parasitic traditional medicine based on 3S technology.