| Objective:In this study,in order to compare the in vitro penetration effect of nano-microneedle and iontophoresis,diclofenac sodium gel was used to permeate through the skin of SD rats in vitro,and the research indexes before and after penetration were compared,including cumulative penetration,transdermal penetration rate and pathological sections,so as to provide some reference for the discovery of new techniques in the application of transdermal drug delivery in bone injury and sports medicine of traditional Chinese medicine.Experimental materials and methods:(1)In vitro penetration test of SD rat skin:(1)Animal skin treatment:after the cervical vertebrae of 9 SD rats were dislocated,the abdominal hair was shaved off with a razor,and then the abdominal skin of the rats was removed with a scalpel,the size of which was 2×3cm~2.After taking off the skin,the residual hair was scraped off with a razor,the abdominal skin of the rat was stripped off,and the subcutaneous adipose tissue was removed,that is,the isolated rat skin was obtained.Rinse the skin sample repeatedly with 0.9%sodium chloride solution and distilled water until the rinse liquid is free of turbidity.The skin samples were dried with filter paper,wrapped in aluminum foil,stored in refrigerator at-20℃,thawed before use and restored to room temperature.(2)Grouping:The treated isolated rat skin was divided into three groups,blank control group in group A,iontophoresis group in group B and nano-microneedle group in group C.there were3 rats in vitro in each group.(3)In vitro diffusion test:TK-12A type Franz test diffusion cell was used in each group.The skin samples of each group were thawed to room temperature.The isolated rat skin of group A and group B were not treated.In group C,nano-microneedle was used to treat the isolated rat skin.the treatment method was to keep the needle body perpendicular to the skin surface,apply a pressure of about 10N for 2 minutes,remove the nano-microneedle and wash it..It was fixed in the receiving room where the receiving solution was injected,the inner side of the skin specimen was facing the receiving chamber,and the cuticle of the rat skin was facing the device delivery chamber.The skin and the two chambers were attached to each other,and the effective release area was 3.14cm~2.The volume of the administration room was 6.5ml,and 2mg diclofenac sodium gel and 2ml 0.9%sodium chloride solution were added to the administration room,respectively.Group B put the ion introduction positive and negative electrode in the administration room,which was not released from the skin.Turn on the power supply,turn on the iontophoresis instrument,set the electrical signal parameters(current frequency 100 Hz,duty cycle 1,current density0.2m A/cm2,iontophoresis time 5 h),rotational speed 600 rpm min,receiving liquid temperature 37±0.1℃,receiver chamber volume 15ml).1m L receptive solution was absorbed 12 hours after administration,and the same amount of isothermal receptive solution was added at the same time after each sample.(3)After the absorbed sample was filtered by microporous membrane(0.22μm),the concentration was determined by HPLC,and the cumulative permeation amount and transdermal rate were calculated.The experimental data were expressed as x±SD.One-way ANOVA was used to analyze the experimental data,and t-test was ifferused to compare the dences between the two groups.(2)histological observation:The above-mentioned rat skin which completed the transdermal experiment in vitro was fixed in formalin(10%formaldehyde solution).After wax embedding,hematoxylin-eosin(HE)staining was performed.The pathological sections of the longitudinal section of the skin were prepared.The skin slices were placed under an inverted microscope to observe the skin structure and collect images.Results:(1).The cumulative permeation volume Q of group A,B and C in 12 hours was116.93±1.65μg/cm~2,139.80±1.98μg/cm~2,160.91±2.19μg/cm~2;diffusion rate J was9.076μg/(cm~2*h),10.842μg/(cm~2*h),12.164μg/(cm~2*h),respectively.There was significant difference between group An and group B and C(P<0.05),B).The cumulative osmotic volume and diffusion rate of group C were better than those of group A.There was significant difference between group B and group C(P<0.05).The cumulative osmotic volume and diffusion rate of group B in),C were better than those in group B.(2)the changes of skin structure of rats:there was no significant change in the skin structure of SD rats in group An and B,but small pinholes could be seen in the dermis of group C,and the subcutaneous tissue damage was less.Conclusion:(1)Nano-microneedle and iontophoresis can significantly promote the penetration of rat skin in vitro.(2)Nano-microneedle has a better effect on the penetration of rat skin in vitro than iontophoresis.(3)both nano-microneedle and iontophoresis have little break to skin structure,no pain,no bleeding,but the operating conditions of transdermal administration of nano-microneedle are more convenient.This study provides more references for exploring new methods of transdermal drug delivery and improving the effect of transdermal drug delivery. |
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