ABSTRACT
BACKGROUND: As an immune-mediated skin disease, psoriasis encounters therapeutic challenges on topical drug development due to the unclear mechanism, and complicated morphological and physiological changes in the skin. METHODS: In this study, imiquimod-induced psoriatic mouse skin (IMQ-psoriatic skin) was chosen as the in vitro pathological model to explore the penetration behaviors of drugs and nanoparticles (NPs). RESULTS: Compared with normal skin, significantly higher penetration and skin accumulation were observed in IMQ-psoriatic skin for all the three model drugs. When poorly water-soluble curcumin was formulated as NPs that were subsequently loaded in gel, the drug's penetration and accumulation in both normal and IMQ-psoriatic skins were significantly improved, in comparison with that of the curcumin suspension. Interestingly, the NPs' size effect, in terms of their penetration and accumulation behaviors, was more pronounced for IMQ-psoriatic skin. Furthermore, by taking three sized FluoSpheres® as model NPs, confocal laser scanning microscopy demonstrated that the penetration pathways of NPs no longer followed the hair follicles channels, instead they were more widely distributed in the IMQ-psoriatic skin. CONCLUSION: In conclusion, the alternation of the IMQ-psoriatic skin structure will lead to the enhanced penetration of drug and NPs, and should be considered in topical drug formulation and further clinical practice for psoriasis therapy.
Subject(s)
Aminoquinolines/toxicity , Anti-Inflammatory Agents, Non-Steroidal/administration & dosage , Curcumin/administration & dosage , Nanoparticles/administration & dosage , Psoriasis/drug therapy , Skin/drug effects , Adjuvants, Immunologic/toxicity , Animals , Anti-Inflammatory Agents, Non-Steroidal/chemistry , Curcumin/chemistry , Disease Models, Animal , Female , Imiquimod , Mice , Mice, Inbred C57BL , Nanoparticles/chemistry , Psoriasis/chemically induced , Psoriasis/pathology , Skin/pathologyABSTRACT
The aim of this work is to prepare and characterize curcumin-loaded methoxy poly(ethylene glycol)-poly(lactide) (mPEG-PLA)/D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) mixed micelles (CUR-MPP-TPGS-MMs), analyze the influence of formulation on enhancing the solubility of curcumin in water, and evaluate the improvement of intestinal absorption after oral administration. CUR-MPP-TPGS-MMs were prepared using the thin film diffusion method and optimized with the uniform design. The optimal CUR-MPP-TPGS-MMs were provided with high drug-loading (16.1%), small size (46.0 nm) and spherical shape. Low critical micelle concentration (CMC) and superior dilution stability showed that CUR-MPP-TPGS-MMs could keep integrity during the dilution of gastrointestinal fluid. In vitro drug release study indicated a sustained release of curcumin from CUR-MPP-TPGS-MMs in simulated gastrointestinal solution. The absorption mechanism of passive diffusion was obtained by measuring in situ intestinal absorption of CUR-MPP-TPGS-MMs in rats, and the best absorption segment was found to be the duodenum. The pharmacokinetics was evaluated in rats at the dose of 75 mg/kg by intragastric administration. The Cmax and mean retention time (MRT0-24) for CUR-MPP-TPGS-MMs were both increased, and the relative bioavailability of micelle formulation to curcumin suspension was 927.3%. These results suggested that mPEG-PLA/TPGS mixed micelle system (MPP-TPGS-MMs) showed great potential in improving oral bioavailability of curcumin.
