Human Skin Permeation Enhancement Using PLGA Nanoparticles Is Mediated by Local pH Changes

Application of Doxorubicin-loaded PLGA nanoparticles targeting both tumor cells and cancer-associated fibroblasts on 3D human skin equivalents mimicking melanoma and cutaneous squamous cell carcinoma

Nanoparticle (NP) use in cancer therapy is extensively studied in skin cancers. Cancer-associated fibroblasts (CAFs), a major tumor microenvironment (TME) component, promote cancer progression, making dual targeting of cancer cells and CAFs an effective therapy. However, dual NP-based targeting therapy on both tumor cells and CAFs is poorly investigated in skin cancers. Herein, we prepared and characterized doxorubicin-loaded PLGA NPs (DOX@PLGA NPs) and studied their anti-tumor effects on cutaneous melanoma (SKCM)(AN, M14) and cutaneous squamous cell carcinoma (cSCC) (MET1, MET2) cell lines in monolayer, as well as their impact on CAF deactivation. Then, we established 3D full thickness models (FTM) models of SKCM and cSCC using AN or MET2 cells on dermis matrix populated with CAFs respectively, and assessed the NPs' tumor penetration, tumor-killing ability, and CAF phenotype regulation through both topical administration and intradermal injection. The results show that, in monolayer, DOX@PLGA NPs inhibited cancer cell growth and induced apoptosis in a dose- and time-dependent manner, with a weaker effect on CAFs. DOX@PLGA NPs reduced CAF-marker expression and had successful anti-tumor effects in 3D skin cancer FTMs, with decreased tumor-load and invasion. DOX@PLGA NPs also showed great delivery potential in the FTMs and could be used as a platform for future functional study of NPs in skin cancers using human-derived skin equivalents. This study provides promising evidence for the potential of DOX@PLGA NPs in dual targeting therapy for SKCM and cSCC.

Electrical Impedance Spectroscopy Quantifies Skin Barrier Function in Organotypic In Vitro Epidermis Models

Three-dimensional human epidermal equivalents (HEEs) are a state-of-the-art organotypic culture model in preclinical investigative dermatology and regulatory toxicology. In this study, we investigated the utility of electrical impedance spectroscopy (EIS) for noninvasive measurement of HEE epidermal barrier function. Our setup comprised a custom-made lid fit with 12 electrode pairs aligned on the standard 24-transwell cell culture system. Serial EIS measurements for 7 consecutive days did not impact epidermal morphology, and readouts showed comparable trends with HEEs measured only once. We determined 2 frequency ranges in the resulting impedance spectra: a lower frequency range termed EISdiff correlated with keratinocyte terminal differentiation independent of epidermal thickness and a higher frequency range termed EISSC correlated with stratum corneum thickness. HEEs generated from CRISPR/Cas9-engineered keratinocytes that lack key differentiation genes FLG, TFAP2A, AHR, or CLDN1 confirmed that keratinocyte terminal differentiation is the major parameter defining EISdiff. Exposure to proinflammatory psoriasis- or atopic dermatitis-associated cytokine cocktails lowered the expression of keratinocyte differentiation markers and reduced EISdiff. This cytokine-associated decrease in EISdiff was normalized after stimulation with therapeutic molecules. In conclusion, EIS provides a noninvasive system to consecutively and quantitatively assess HEE barrier function and to sensitively and objectively measure barrier development, defects, and repair.

Super-Antioxidant Vitamin A Derivatives with Improved Stability and Efficacy Using Skin-Permeable Chitosan Nanocapsules

Retinyl palmitate (RP) is a retinol ester with strong antioxidant and anti-inflammatory properties as an antiwrinkle agent. However, it has poor aqueous solubility and easily degrades into inactive forms for topical applications. Therefore, we developed chitosan-coated nanocapsules (ChiNCs) to encapsulate RP using a simple nanoprecipitation method for protection against physiological conditions and to enable deep skin penetration. The as-prepared RP-loaded nanocapsules (RP@ChiNCs) loaded with approximately 5 wt.% RP exhibited a hydrodynamic diameter of 86 nm and surface charge of 24 mV. They had adequate stability to maintain their physicochemical properties after lyophilization in a biological buffer. Notably, ChiNCs provided RP with remarkable protection against degradation for 4 weeks at 37 °C. Thus, RP@ChiNCs exhibited good antioxidant activity in situ for sufficiently long periods without considerable changes in their efficacy. Furthermore, ChiNCs enhanced the skin penetration of lipophilic RP based on the inherent nature of chitosan. RP@ChiNCs exhibited good in vitro antioxidant and anti-inflammatory effects without causing any cytotoxicity in dermal fibroblasts. Accordingly, they promoted cell proliferation in a wound-scratch test and enhanced collagen synthesis. These results suggest that RP@ChiNCs are promising candidates for cosmetic and biomedical applications.

The Fundamental Role of Lipids in Polymeric Nanoparticles: Dermal Delivery and Anti-Inflammatory Activity of Cannabidiol

This report presents a nanoparticulate platform for cannabidiol (CBD) for topical treatment of inflammatory conditions. We have previously shown that stabilizing lipids improve the encapsulation of CBD in ethyl cellulose nanoparticles. In this study, we examined CBD release, skin permeation, and the capability of lipid-stabilized nanoparticles (LSNs) to suppress the release of IL-6 and IL-8. The nanoparticles were stabilized with cetyl alcohol (CA), stearic acid (SA), lauric acid (LA), and an SA/LA eutectic combination (SALA). LSN size and concentration were measured and characterized by differential scanning calorimetry (DSC), in vitro release of loaded CBD, and skin permeability. IL-6 and IL-8 secretions from TNF-α-induced HaCaT cells were monitored following different LSN treatments. CBD released from the LSNs in dispersion at increasing concentrations of polysorbate 80 showed non-linear solubilization, which was explained by recurrent precipitation. A significant high release of CBD in a cell culture medium was shown from SALA-stabilized nanoparticles. Skin permeation was >30% lower from SA-stabilized nanoparticles compared to the other LSNs. Investigation of the CBD-loaded LSNs' effect on the release of IL-6 and IL-8 from TNF-α-induced HaCaT cells showed that nanoparticles stabilized with CA, LA, or SALA were similarly effective in suppressing cytokine release. The applicability of the CBD-loaded LSNs to treat topical inflammatory conditions has been supported by their dermal permeation and release inhibition of pro-inflammatory cytokines.

The Contest of Nanoparticles: Searching for the Most Effective Topical Delivery of Corticosteroids

Owing to their complicated pathophysiology, the treatment of skin diseases necessitates a complex approach. Conventional treatment using topical corticosteroids often results in low effectiveness and the incidence of local or even systemic side effects. Nanoformulation of potent anti-inflammatory drugs has been selected as an optimal strategy for enhanced topical delivery of corticosteroids. In order to assess the efficiency of various nanoformulations, we formulated hydrocortisone (HC) and hydrocortisone-17-butyrate (HCB) into three different systems: lipid nanocapsules (LNC), polymeric nanoparticles (PNP), and ethosomes (ETZ). The systems were characterized using dynamic light scattering for their particle size and uniformity and the morphology of nanoparticles was observed by transmission electron microscopy. The nanosystems were tested using ex vivo full thickness porcine and human skin for the delivery of HC and HCB. The skin penetration was observed by confocal microscopy of fluorescently labelled nanosystems. ETZ were proposed as the most effective delivery system for both transdermal and dermal drug targeting but were also found to have a profound effect on the skin barrier with limited restoration. LNC and PNP were found to have significant effects in the dermal delivery of the actives with only minimal transdermal penetration, especially in case of HCB administration.

Poly(lactic-co-glycolic) Acid (PLGA) Nanoparticles and Transdermal Drug Delivery: An Overview

BACKGROUND

Biodegradable polymeric nanoparticles have garnered pharmaceutical industry attention throughout the past decade. PLGA [Poly(lactic-co-glycolic acid)] is an excellent biodegradable polymer explored for the preparation of nanoparticles that are administered through various routes like intravenous and transdermal. PLGA's versatility makes it a good choice for the preparation of nanoparticles.

OBJECTIVE

The main objective of this review paper was to summarize methods of preparation and characterization of PLGA nanoparticles along with their role in the transdermal delivery of various therapeutic agents.

METHODS

A literature survey for the present review paper was done using various search engines like Pubmed, Google Scholar, and Science Direct.

RESULTS

In comparison to traditional transdermal administration systems, PLGA nanoparticles have demonstrated several benefits in preclinical investigations, including fewer side effects, low dosage frequency, high skin permeability, and simplicity of application.

CONCLUSION

PLGA nanoparticles can be considered efficient nanocarriers for the transdermal delivery of drugs. Nevertheless, the clinical investigation of PLGA nanoparticles for the transdermal administration of therapeutic agents remains a formidable obstacle.

In Vitro, Ex Vivo, and In Vivo Evaluation of Nanoparticle-Based Topical Formulation Against Candida albicans Infection

Ketoconazole is commonly used in the treatment of topical fungal infections. The therapy requires frequent application for several weeks. Systemic side effects, allergic reactions, and prolonged treatment are often associated with non-compliance and therapy failure. Hence, we developed an optimized topical antifungal gel that can prolong the release of drug, reduce systemic absorption, enhance its therapeutic effect, and improve patient compliance. Ketoconazole-loaded PLGA nanoparticles were prepared by the emulsion/solvent evaporation method and were characterized with respect to colloidal properties, surface morphology, and drug entrapment efficiency. The optimized ketoconazole-loaded PLGA nanoparticles and commercially available silver nanoparticles were incorporated into a Carbopol 934P-NF gel base. This arrangement was characterized and compared with commercially available 2% ketoconazole cream to assess physical characteristics of the gel, in vitro drug release, ex vivo skin permeation and retention, and in vivo studies on Wister male albino rats. The results showed that polymeric PLGA nanoparticles were very effective in extending the release of ketoconazole in our optimized formulation. Nanoparticles were smooth, spherical in shape, and below 200 nm in size which is consistent with the data obtained from light scattering and SEM images. The ex vivo data showed that our gel formulation could strongly reduce drug permeation through the skin, and more than 60% of the drug was retained on the upper surface of the skin in contrast to 38.42% of the commercial cream. The in vivo studies showed that gel formulation could effectively treat the infection. This study demonstrates that our topical gel could be effective in sustaining the release of drug and suggests its potential use as a possible strategy to combat antifungal-resistant Candida albicans.

Superhydrophilic PLGA-Graft-PVP/PC Nanofiber Membranes for the Prevention of Epidural Adhesion

Background

The frequent occurrence of failed back surgery syndrome (FBSS) seriously affects the quality of life of postoperative lumbar patients. Epidural adhesion is the major factor in FBSS.

Purpose

A safe and effective antiadhesion material is urgently needed.

Methods

A superhydrophilic PLGA-g-PVP/PC nanofiber membrane (NFm) was prepared by electrospinning. FTIR was performed to identify its successful synthesis. Scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, and water contact angle measurement were performed. CCK-8 assays were performed in primary rabbit fibroblasts (PRFs) and RAW264.7 cells to explore the cytotoxicity of PLGA-g-PVP/PC NFm. Calcein-AM/PI staining was used to measure the adhesion status in PRFs. ELISA was performed to measure the concentrations of TNF-α and IL-10 in RAW264.7 cells. In addition, the anti-epidural adhesion efficacy of the PLGA-g-PVP/PC NFm was determined in a rabbit model of lumbar laminectomy.

Results

The PLGA-g-PVP/PC NFm exhibited ultrastrong hydrophilicity and an appropriate degradation rate. Based on the results of the CCK-8 assays, PLGA-g-PVP/PC NFm had no cytotoxicity to PRFs and RAW264.7 cells. Calcein-AM/PI staining showed that PLGA-g-PVP/PC NFm could inhibit PRF adhesion. ELISAs showed that PLGA-g-PVP/PC NFm could attenuate lipopolysaccharide-induced macrophage activation. In vivo experiments further confirmed the favorable anti-epidural adhesion effect of PLGA-g-PVP/PC NFm and the lack of a strong inflammatory response.

Conclusion

In this study, PLGA-g-PVP/PC NFm was developed successfully to provide a safe and effective physical barrier for preventing epidural adhesion. PLGA-g-PVP/PC NFm provides a promising strategy for preventing postoperative adhesion and has potential for clinical translation.