Improving topical treatments for skin diseases

Towards the personalization of gelatin-based 3D patches: a tunable porous carrier for topical applications

Cell-free based therapies, for example, the use of the cell secretome, have emerged as a promising alternative to conventional skin therapies using bioactive and, when combined with 3D printing technologies, allow the development of personalized dosage forms. This research work aimed to develop gelatin-based patches with controlled network topology via extrusion 3D printing, loaded with cell culture medium as a model of the secretome, and applicable as vehicles for topical delivery. Inks were optimized through rheological and printing assays, and the incorporation of medium had minor effects in printability. Regarding network topology, grid infills rendered more defined structures than the triangular layout, depicting clearer pores and pore area consistency. Release studies showed that filament spacing and infill pattern influenced the release of rhodamine B (model bioactive) and bovine serum albumin (model protein). Moreover, the grid patches (G-0.7/1/0.7), despite having around a seven-fold higher mean pore area than 0.7-mm triangular ones (T-0.7), showed a similar release profile, which can be linked to the network topology of the printed structures This work provided insight on employing (bio)printing in the production of carriers with reproducible and controlled pore area, able to incorporate cell-derived secretome and to be quickly tailored to the patient's lesions.

Localized topical drug delivery systems for skin cancer: Current approaches and future prospects

Topical drug delivery presents a novel substitute to the conventional drug-distribution routes of oral delivery and injection. Apart from the simplicity and non-invasiveness, the skin also serves as a “reservoir” that sustains administration over a period of days. Nanocarriers provide new potential for the treatment of skin disease. The skin’s barrier function offers a considerable obstacle for the potential nanocarriers to infiltrate into the tissue. However, the barrier is partially weakened in case of damage or inflammation, as in the case of skin cancer. Nanoparticles may promote the penetration of the skin. Extensive research has been done into producing nanoparticles for topical distribution; nevertheless, relatively little progress has been achieved in transferring them to the clinic for treating skin malignancies. The prior art features the critical concepts of skin malignancies and techniques in current clinical care. The present review gives a complete viewpoint of the numerous nanoparticle technologies studied for the topical treatment of skin malignancies and outlines the hurdles that hamper its advancement from the bench to the bedside. The review also intends to give knowledge of the routes that control nanoparticle penetration into the skin and their interactions inside the tissue.

Solid Lipid Nanoparticles for Topical Drug Delivery: Mechanisms, Dosage Form Perspectives, and Translational Status

Solid lipid nanoparticles (SLNs) have shown potential as a novel lipid-based drug delivery system for the topical applications of innumerable therapeutic compounds. However, the mechanisms governing the absorption and cellular uptake of SLNs through topical route, along with the mechanism of drug release from SLNs are still ambiguous, and require further investigation. In addition, the selection of an appropriate dosage form/formulation base is essential for ease of application of SLNs and to enhance dermal and transdermal delivery. Upscaling and regulatory approvals are other challenges that may impede the clinical translation of SLNs. Therefore, this review focusses on different mechanisms involved in skin penetration and cellular uptake of SLNs. This is followed by a comprehensive discussion on the physicochemical properties of SLNs including various formulation and dosage form factors, which might influence the absorption of SLNs through the skin. Finally, translational status with respect to scale-up and regulatory aspects are also discussed. This review will be useful to researchers with an interest in topical applications of SLNs for the efficient delivery of drugs and cosmetics.

Topical Anti-Inflammatory Activity of Essential Oils of Alpinia calcarata Rosc., Its Main Constituents, and Possible Mechanism of Action

This study aimed at investigating the anti-inflammatory potential of essential oil from rhizome and leaf of Alpinia calcarata Rosc. (ACEO) with the focus of its topical anti-inflammatory activity along with its dominant compounds 1,8-cineole and α-terpineol using mouse ear edema model. ACEOs were analyzed by GC-MS. The anti-inflammatory activity was determined by studying the inhibition of overproduction of proinflammatory mediators-nitric oxide, reactive oxygen species, prostaglandins, cyclooxygenases, and cytokines induced by lipopolysaccharides in murine macrophages. Topical anti-inflammatory and antinociceptive activity was studied by 12-O-tetradecanoylphorbol-13-acetate (TPA) induced skin inflammation and formalin-induced pain model in mice, respectively. Rhizome oil has 1,8-cineole (31.08%), α-terpineol (10.31%), and fenchyl acetate (10.73%) as major compounds whereas the ACEO from leaves has 1,8-cineole (38.45%), a-terpineol (11.62%), and camphor (10%). ACEOs reduced the production of inflammatory mediators in vitro in a concentration-dependent manner. Further, ACEO and its major compounds reduced ear thickness, weight, myeloperoxidase, and cytokines significantly (p < 0.01) in mouse ear. Dose-dependent reduction in flinching and licking in both the phases of pain sensation concludes the topical analgesic effect. Our findings suggest the potency of topical use of ACEOs for inflammatory disease conditions.

Trans-resveratrol-loaded nonionic lamellar liquid-crystalline systems: structural, rheological, mechanical, textural, and bioadhesive characterization and evaluation of in vivo anti-inflammatory activity

Resveratrol (Res) is a common phytoalexin present in a few edible materials, such as grape skin, peanuts, and red wine. Evidence has shown the beneficial effects of Res on human health, which may be attributed to its anti-inflammatory activity. However, the poor aqueous solubility of Res limits its therapeutic effectiveness. Therefore, the use of nanostructured delivery systems for Res, such as liquid-crystalline systems, could be beneficial. In this study, we aimed to develop, characterize, and determine the in vivo effectiveness of Res-loaded liquid-crystalline systems. Systems containing copaiba balsam oil, polyethylene glycol-40 hydrogenated castor oil, and water were designed. Results of polarized light microscopy, small-angle X-ray scattering, texture-profile analysis, and flow-rheology analysis showed that the Res-loaded liquid-crystalline system had a lamellar structure, textural and mechanical (hardness, compressibility, and adhesiveness) properties, and behaved as a non-Newtonian fluid, showing pseudoplastic behavior upon skin application. Furthermore, all liquid-crystalline systems presented bioadhesive properties that may have assisted in maintaining the anti-inflammatory activity of Res, since the topical application of the Res-loaded lamellar mesophase liquid crystals resulted in edema inhibition in a carrageenan-induced paw-inflammation mouse model. Therefore, Res-loaded lamellar mesophases represent a promising new therapeutic approach for inhibition of skin inflammation.

Anti-inflammatory effects of Bryophyllum pinnatum (Lam.) Oken ethanol extract in acute and chronic cutaneous inflammation

ETHNOPHARMACOLOGICAL RELEVANCE

Bryophyllum pinnatum (Lam.) Oken (Crassulaceae), popularly known in Brazil as "folha-da-fortuna", is a plant species used in folk medicine for the external and internal treatment of inflammation, infection, wound, burn, boil, ulcers and gastritis, and several other diseases. The present study aimed to perform the chemical characterization and the evaluation of the topical anti-inflammatory effect of the ethanol extract of Bryophyllum pinnatum leaves (EEBP) in acute and chronic mice ear edema models induced by different irritant agents.

MATERIALS AND METHODS

The EEBP chemical characterization was performed by HPLC-UV DAD. Ear edema on Swiss mice was induced by the topical application of Croton oil (single and multiple applications), arachidonic acid, phenol, capsaicin and ethyl phenylpropiolate (EPP). The topical anti-inflammatory effect of EEBP was evaluated by measuring the ear weight (acute inflammation models) and thickness (chronic inflammation model). Histopathological analyses of ear tissue samples sensitized with Croton oil (single and multiple applications) were also performed.

RESULTS

The flavonoids rutin, quercetin, luteolin and luteolin7-O-β-d-glucoside were detected in EEBP. Topical application of EEBP significantly (P<0.001) inhibited the ear edema induced by Croton oil single application (inhibition of 57%), arachidonic acid (inhibition of 67%), phenol (inhibition of 80%), capsaicin (inhibition of 72%), EPP (inhibition of 75%) and Croton oil multiple application (55% after 9 days). Histopathological analyses confirmed the topical anti-inflammatory effect of EEBP since it was observed reduction of edema, epidermal hyperplasia, inflammatory cells infiltration and vasodilation.

CONCLUSIONS

The results suggest that EEBP is effective as a topical anti-inflammatory agent in acute and chronic inflammatory processes possibly due to inhibition of arachidonic acid pathway, which justify the traditional use of Bryophyllum pinnatum as a remedy for skin disorders.