Transdermal Delivery Of Camptothecin Derivative By Hyalutonic Acid Based Nanoemulsion For Keloid Repair

Hyaluronic acid based nanoemulsion (HANs) transdermal drug deliverysystem shows many advantages on skin penetration, measured dosing, drug delivery,drug controlled-release, extended efficacy and positioning shallow lesions.10,11-methylenedioxy camptothecin (MD-CPT) is representative of a camptothecinderivatives, a good anti-tumor agent, and can effectively impede DNA replication,block mitosis, and inhibit cell proliferation. However, the physical and chemicalnature of MD-CPT limits the applications such as hydrophobicity, weak stability ofthe lactone ring. HANs as carrier for the MD-CPT can overcome its water-insoluble,promote the body’s absorption and improve bioavailability, increase drug targeting,reduce side effects, maintain the plasma concentration, prolong the half-life andimprove efficacy. Keloid is considered to be a benign tumor, which is characterizedby excessive proliferation of fibroblasts. In this article HANs loaded MD-CPT is usedin keloid repair study as a mild non-invasive transdermal drug delivery system.Amphiphilic hyaluronic acid monoglyceride derivative (HA-GMS) wassuccessfully synthesized and detected by IR, NMR. FITC labeled HA-GMS. Inhemolysis experiment, HA-GMS showed low erythrocyte membrane-damaging effect.The MTT survival assay indicated no significant cytotoxicity.Using ultrasonic emulsification method, HANs loaded MD-CPT weresuccessfully synthesized with different HA-GMS: MD-CPT w/w ratio whichdemonstrated particle size of50~200nm, zeta potential absolute value of10~20mV,negatively charged, good distribution and uniformity, and an almost spherical shape.The MD-CPT/HANs maintained good stability at pH4.0~7.4, the weak acid skinenvironment.Rhodanmine B labeled HA-GMS performed desirable skin permeable capacityacross stratum corneum and the drug was transferred to the dermis in4h, and thenanoemulsion with optimized preparation conditions was verified the highest effective drug permeability.Plasma concentration of MD-CPT analysis and urine test demonstrated the restMD-CPT entered into the blood circulation, eventually excreted through metabolismwithout body burden. In vivo imaging system intuitively reflected the distribution oftransdermal drug in mice and the drug content of various organs/tissues. The longerdrug residence at topical area with treatment could provide a continuous andcontrollable, extended efficacy, which was beneficial to superficial lesions therapy.Compared with different cell lines including HSF, HUVECS, MCF-7and N2a,MD-CPT demonstrated selective effect on cell growth inhibition, phagocytosis andcell cycle regulation, obviously biased division-active hyperplastic cells.MD-CPT/HANs performed desirable skin permeable capacity across humankeloid skin and the drug was transferred directly to keloid lesion area. MD-CPT wasdelivered percutaneously higher than the control group (MD-CPT ethanol solution).FITC-HANs could be successfully internalized by keloid fibroblast (KF) and deliverMD-CPT towards nucleus, inhibited the proliferation of KF, in a dose-dependentmanner. The growth-inhibitory effect was further clarified upon cell cycle regulation,which arrested cells at G1/S and prevented them entry into mitosis. KF geneexpression measured by real time PCR demonstrated plasminogen activatorinhibitor-1(PAI-1) was significantly down-regulated and TGF-β, Smad3, Smad7up-regulated, which suggested that TGF-β/SMAD-> PAI-1was blocked by Smad7.Western Blot results demonstrated Smad2/3phosphorylation levels decreasedsignificantly, which confirmed that Smad7could hamper Smad2/3phosphorylationand then block TGF-β/SMAD signaling pathway, and decrease gene expression ofPAI-1, which was beneficial to inhibit keloid.In summary, HA-based nanoemulsion system for MD-CPT as transdermaldelivery system was evaluated on the biological properties in vitro and in vivo,demonstrated good skin permeability, cell-specificity, pharmacokinetic properties,and applied to keloid therapy study. The study indicated that as transdermal deliverysystem of HANs loaded MD-CPT is potential for keloid repair therapy.