[Transdermal delivery of Gentiana macrophylla complex components system under micro-needle conditions].

The purpose of this study is to investigate the transdermal delivery characteristics of Gentiana macrophylla complex components system through different parts of the skin under micro-needles conditions. Two-chamber diffusion cells were used, different parts of isolated skin and micro-needle pretreated isolated mouse skin were applied separately, high performance liquid chromatography (HPLC) similarity evaluation methods were used to evaluate transdermal delivery characteristics of Gentiana macrophylla complex components system on receiving pool and the permeation rate and penetration amount of Gentiopicroside at different parts of mouse skin. In the 24 h, the similarity between receiving fluid which was on passive transdermal delivery and micro-needle transdermal delivery conditions and original fluid were ranged from 83.0% to 98.9%; By the micro-needle pretreatment with different parts of the mouse skin, the time that Gentiana macrophylla complex components system though abdominal skin to the receiving fluid which reached 90% similarity compared with that of original fluid was 4 h, which was 18 h at back skin and 12 h at neck skin separately. Micro-needles can be used as the ideal ingredients for traditional Chinese medicine complex transdermal delivery; transdermal absorption time delay could be greatly reduced and its bioavailability was improved. The permeation rate and similarity to original liquid of Chinese medicine complex components increased significantly in the abdominal skin relative to the neck and back skin under micro-needle conditions.

Super-short solid silicon microneedles for transdermal drug delivery applications.

In this study, the super-short microneedles with a length of 70-80 microm were fabricated using silicon wet etching technology. As evident from the visual inspection of pierced human skin, appearance of blue spots array after Evans Blue (EB) application indicated that the super-short microneedles were able to pierce into skin by pressing and swaying against the microneedles backing layer continually with a finger. The micro-conduits created in skin were validated by histological examination. Transport studies revealed that: (i) skin pretreated with super-short microneedles resulted in a remarkable enhancement of the galanthamine (GAL) transport, and the permeated amount increased as the insertion force increased; (ii) the super-short microneedles with flat tips were better than that with sharp tips for enhancing skin permeability; (iii) the longer time of super-short microneedles detained in skin resulted in a higher increase of skin permeability; (iv) there was no linear correlation between the GAL permeated through skin and the number of microneedles. The EIIIA(+) (526 bp) segment, a very sensitive marker of tissue injury, did not expressed in the skin pierced by super-short microneedles. Meanwhile, the skin pretreated with super-short microneedles did not infected after incubation with the Staphylococcus aureus. These results suggest that super-short microneedles may be a safe and efficient alternative for transdermal drug delivery of hydrophilic molecules.