Effect of Olive Oil Acidity on Skin Delivery of Diclofenac: In Vitro Evaluation and Ex Vivo Skin Permeability Studies

Formulation Development and In Vitro/In Vivo Characterization of Methotrexate-Loaded Nanoemulsion Gel Formulations for Enhanced Topical Delivery

Methotrexate-loaded oil-in-water nanoemulsion formulations were prepared using the high shear homogenization technique. A drug excipient study (ATR-FTIR) was carried out to investigate the compatibility between the drug, the polymers, and its admixtures. The thermal stability of the nanoemulsion formulations was evaluated by subjecting them to a heating and cooling cycle. The prepared nanoemulsion formulations (FNE1 to FNE6) were evaluated for particle size, PDI value, and entrapment efficiency (EE). They were analyzed for morphological information using transmission electron microscopy. The drug (methotrexate)-loaded nanoemulsion formulations (FNE2, FNE4, and FNE6) were then converted into nanoemulsion gel formulations by adding 1% chitosan (polymer) as a gelling agent. The nanoemulsion gel formulations (FNEG2, FNEG4, and FNEG6) were investigated for physicochemical parameters, viscosity, spreadability, extrudability, drug content, and skin irritation. Various penetration enhancers (olive oil, clove, and almond oil) were employed to examine the potency of the prepared nanoemulsion gel formulations. In vitro drug release, ex vivo permeation, skin drug retention, and stability tests were carried out for evaluation of the prepared nanoemulsion gel formulations (FNEG2, FNEG4, and FNEG6). The data obtained from the in vitro study were subjected to the kinetic model, and the Korsemeyer-Peppas model was best fitted to the data. The nanoemulsion gel formulation FNEG6 showed the maximum controlled drug release and followed an anomalous, non-Fickian release mechanism. The use of almond oil in the preparation of the nanoemulsion gel formulation FNEG6 helped the penetration of the drug across stratum corneum and the restructuring of the properties of skin and resulted in a higher penetration and retention of methotrexate in a deeper layer of the skin. The current study concluded that the methotrexate-loaded nanoemulsion gel formulation FNEG6 showed the best optimum release, permeation, and retention results as compared to the available oral tablets' formulations, followed by a low serum concentration and the maximum drug retention, which is beneficial in treating skin infections and reducing systemic toxicity.

Histopathological Evaluation of the Healing Process of Standardized Skin Burns in Rabbits: Assessment of a Natural Product with Honey and Essential Oils

Skin burns are one of the most difficult medical problems. Recently, studies have been directed towards development of natural products in order to identify effective and safe remedies. In the present study, we evaluated the efficacy of a natural composite (formulated from honey and essential oils) compared with MEBO® (0.25% β-sitosterol) and DERMAZIN® creams (1% silver-sulfadiazine) in the treatment of thermally induced skin burns. For this purpose, four burn-wounds were created on the back of male New Zealand rabbits (n = 10) using a thermal stamp under the effect of general anesthesia. Each wound represents one of the following groups: non-treated, natural composite-cream, MEBO®-cream, and silver-sulfadiazine treated groups, respectively. Treatments were applied once a day topically until one of these wounds appeared to be healed grossly. The non-treated group received no treatment. Grossly, skin burns have been healed after 28 days of the treatment in all groups except of the non-treated group. The healing efficacy of the natural composite, MEBO® and silver-sulfadiazine creams was quite similar macroscopically. However, microscopically, the epidermal layer of the composite-cream treated group was more mature than those of both MEBO® and silver-sulfadiazine creams treated groups. In conclusion, the tested composite may be a promising effective and inexpensive treatment of skin burns.