Hexyl-aminolevulinate ethosome-mediated photodynamic therapy against acne: in vitro and in vivo analyses

Ionic Liquid Pretreatment Enhances Skin Penetration of 5-Aminolevulinic Acid: A Promising Scheme for Photodynamic Therapy for Acne Vulgaris

Acne vulgaris is one of the most prevalent skin disorders; it affects up to 85% of adolescents and often persists into adulthood. Topical 5-aminolevulinic acid (ALA)-based photodynamic therapy (PDT) provides an alternative treatment for acne; however, its efficacy is greatly undermined by the limited skin permeability of ALA. Herein, biocompatible ionic liquids (ILs) based on aliphatic acid/choline were employed to enhance the dermal delivery of ALA, thereby improving the efficacy of PDT. In addition to the one-step delivery of ALA by utilizing ILs as carriers, a two-step strategy of pretreating the skin with blank ILs, followed by the administration of free ALA, was employed to test the IL-facilitated dermal delivery of ALA in vitro. The cumulative permeation of ALA through the excised rat skin after IL pretreatment was significantly greater than that in the untreated group, the 20% dimethyl sulfoxide (DMSO) penetration enhancer group, and the one-step group. The penetration efficiency was influenced by formulation and treatment factors, including the type of IL, pretreatment duration, water content in the ILs, and concentration of ALA. In rats, IL pretreatment facilitated faster, greater, and deeper ALA-induced protoporphyrin IX (PpIX) accumulation. Moreover, the IL pretreatment regimen significantly improved the efficacy of ALA-based PDT against acne vulgaris in a rat ear model. The model IL choline citrate ([Ch]3[Cit]1) had a moderate effect on the skin barrier. Trans-epidermal water loss could be recovered 1 h after IL treatment, but no irritation to the rat skin was detected after 7 days of consecutive treatment. It was concluded that biocompatible IL pretreatment enhances the penetration of ALA and thus facilitates the transformation of PpIX and improves the efficacy of PDT against acne vulgaris.

An Overview of Biofilm-Associated Infections and the Role of Phytochemicals and Nanomaterials in Their Control and Prevention

Biofilm formation is considered one of the primary virulence mechanisms in Gram-positive and Gram-negative pathogenic species, particularly those responsible for chronic infections and promoting bacterial survival within the host. In recent years, there has been a growing interest in discovering new compounds capable of inhibiting biofilm formation. This is considered a promising antivirulence strategy that could potentially overcome antibiotic resistance issues. Effective antibiofilm agents should possess distinctive properties. They should be structurally unique, enable easy entry into cells, influence quorum sensing signaling, and synergize with other antibacterial agents. Many of these properties are found in both natural systems that are isolated from plants and in synthetic systems like nanoparticles and nanocomposites. In this review, we discuss the clinical nature of biofilm-associated infections and some of the mechanisms associated with their antibiotic tolerance. We focus on the advantages and efficacy of various natural and synthetic compounds as a new therapeutic approach to control bacterial biofilms and address multidrug resistance in bacteria.

New Insights in Topical Drug Delivery for Skin Disorders: From a Nanotechnological Perspective

Skin, the largest organ in humans, is an efficient route for the delivery of drugs as it circumvents several disadvantages of the oral and parenteral routes. These advantages of skin have fascinated researchers in recent decades. Drug delivery via a topical route includes moving the drug from a topical product to a locally targeted region with dermal circulation throughout the body and deeper tissues. Still, due to the skin's barrier function, delivery through the skin can be difficult. Drug delivery to the skin using conventional formulations with micronized active components, for instance, lotions, gels, ointments, and creams, results in poor penetration. The use of nanoparticulate carriers is one of the promising strategies, as it provides efficient delivery of drugs through the skin and overcomes the disadvantage of traditional formulations. Nanoformulations with smaller particle sizes contribute to improved permeability of therapeutic agents, targeting, stability, and retention, making nanoformulations ideal for drug delivery through a topical route. Achieving sustained release and preserving a localized effect utilizing nanocarriers can result in the effective treatment of numerous infections or skin disorders. This article aims to evaluate and discuss the most recent developments of nanocarriers as therapeutic agent vehicles for skin conditions with patent technology and a market overview that will give future directions for research. As topical drug delivery systems have shown great preclinical results for skin problems, for future research directions, we anticipate including in-depth studies of nanocarrier behavior in various customized treatments to take into account the phenotypic variability of the disease.

Hexyl-Aminolevulinate Ethosomes: a Novel Antibiofilm Agent Targeting Zinc Homeostasis in Candida albicans

Substantial drug resistance afforded by Candida albicans biofilms results in ineffective treatment with conventional drugs and persistent infection. Our previous study showed that hexyl-aminolevulinate ethosomes (HAL-ES) act against C. albicans biofilms and weaken their drug resistance and pathogenicity; however, the mechanism involved remains unclear. Here, we systematically evaluated the effects and mechanisms of HAL-ES on biofilm formation and drug resistance. We found that, in addition to mediating antifungal photodynamic therapy, HAL-ES inhibited the early, developmental, and mature stages of biofilm formation compared with fluconazole, HAL, or ES. Notably, adhesion and hyphal formation were significantly inhibited by postdrug effects even after brief exposure (2 h) to HAL-ES. Its therapeutic effect in vivo also has been demonstrated in cutaneous candidiasis. RNA sequencing and quantitative PCR showed that HAL-ES inhibited ribosome biogenesis by disrupting zinc homeostasis in C. albicans, thereby reducing the translation process during protein synthesis. Furthermore, HAL-ES downregulated the expression of multidrug resistance genes and increased fluconazole susceptibility in C. albicans. Our findings provide a novel and efficient method for the treatment of biofilm resistance in C. albicans infection as well as a basis for the application of HAL-ES. We also describe a new strategy for the treatment of biofilm-related infections via zinc restriction. IMPORTANCE Candida albicans is the most prevalent fungal species of the human microbiota. The medical impact of C. albicans on its human host depends on its ability to form biofilms. The intrinsic resistance conferred by biofilms to conventional antifungal drugs makes biofilm-based infections a significant clinical challenge. In this study, we demonstrate the attenuating effect of HAL-ES on C. albicans biofilm formation and drug resistance. Furthermore, we propose that HAL-ES inhibits protein translation by disrupting zinc homeostasis in C. albicans. This study not only provides a novel and effective therapeutic strategy against C. albicans biofilm but also proposes a new strategy to resolve C. albicans biofilm infection by disrupting zinc homeostasis.