Structural and Functional Analysis of Excised Skins and Human Reconstructed Epidermis with Confocal Raman Spectroscopy and in Microfluidic Diffusion Chambers

Acyclovir (ACV) controls cutaneous herpes, genital herpes, herpes keratitis, varicella zoster, and chickenpox. From previously reported ACV formulations, we continued to explore the permeation behavior of the optimized ACV loaded optimized ethosome (ETHO2R) and elastic liposome (ELP3R) and their respective carbopol gels across artificial membrane, cultured human EpiDerm, and rat skin. Transepidermal water loss (TEWL), scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), and atomic force microscopy (AFM) were used to investigate the mechanistic perspective of permeation behavior. The size values of reformulated ELP3-R and ETHO2-R were observed as 217 and 128 nm, respectively (close to previous report), whereas their respective gels showed as 231 and 252 nm, respectively. ETHO2R showed high elasticity, %EE, and low vesicle size. These were investigated for the diffusion rate of the drug permeation (3 h) across the artificial membrane, cultured human EpiDerm, and rat skin. ETHO2GR showed the highest permeation flux (78.42 µg/cm2/h), diffusion coefficient (8.24 × 10−5 cm2/h), and permeation coefficient (0.67 × 10−3 cm/h) of ACV across synthetic membrane, whereas diffusion coefficient (2.4 × 10−4 cm2/h) and permeation coefficient (0.8 × 10−3 cm/h) were maximum across EpiDerm for ETHO2GR. ETHO2R suspension showed maximized permeation flux (169.58 µg/cm2/h) and diffusion rate (0.293 mg/cm2/h1/2), suggesting the rapid internalization of vesicles with cultured skin cells at low viscosity. A similar observation was revealed using rat skin, wherein the permeation flux (182.42 µg/cm2/h), permeation coefficient (0.3 × 10−2 cm/h), and diffusion rate (0.315 mg/cm2/h1/2) of ETHO2R were relatively higher than ELP3R and ELP3GR. Relative small size (128 nm), low viscosity, ethanol-mediated ultra-deformability, high drug entrapment (98%), and elasticity (63.2) are associated with ETHO2R to provide remarkable permeation behavior across the three barriers. The value of TEWL for ETHO2R (21.9 g/m2h) was 3.71 times higher than untreated control (5.9 g/m2h), indicating ethanol-mediated maximized surficial skin lipid perturbation at 3 h of application, whereas the respective ETHO2GR-treated rat skin had TEWL value (18.6 g/m2h) slightly lower than ETHO2R due to gel-based hydration into the skin. SEL, CLSM, and AFM provided a mechanistic perspective of ETHO2R and ELP3R-mediated permeation across rat skin and carrier-mediated visualization (skin–vesicle interaction). AFM provided detailed nanoscale surface roughness topographical parameters of treated and untreated rat skin as supportive data to SEM and CLSM. Thus, ethosomes ETHO2R and respective gel assisted maximum permeation of ACV across rat skin and cultured human EpiDerm to control cutaneous herpes infection and herpes keratitis.

Section: Resultssupporting

confidence: 92%

Mechanistic of Vesicular Ethosomes and Elastic Liposomes on Permeation Profiles of Acyclovir across Artificial Membrane, Human Cultured EpiDerm, and Rat Skin: In Vitro-Ex Vivo Study

Hussain,

Altamimi,

Afzal

et al. 2023

“…α-Aminophosphonates were dispersed in the following hydrophilic cream base (O/W emulsion ointments) [ 32 , 33 ]: 46 m/m% Petrolatum ointment base, 10 m/m% Propylene glycol (Hungaropharma Zrt., Budapest, Hungary), 4 m/m% Paraffin oil (Hungaropharma Zrt., Budapest, Hungary), 38 m/m% Purified water. The components of the Petrolatum ointment base were 26 m/m% Vaselinum album (Hungaropharma Zrt., Budapest, Hungary), 12 m/m% Cetostearyl alcohol (Molar Chemicals Kft, Halásztelek, Hungary), 10 m/m% Propylene glycol, 8 m/m% Paraffin oil, 4 m/m% Polyoxyethylene sorbitan monostearate (Poly-sorbate 60) (Hungaropharma Zrt.…”

Section: Methodsmentioning

confidence: 99%

Transdermal Delivery of α-Aminophosphonates as Semisolid Formulations—An In Vitro-Ex Vivo Study

Kocsis,

Varga,

Keshwan

et al. 2023

Self Cite

α-Aminophosphonates are organophosphorus compounds with an obvious similarity with α-amino acids. Owing to their biological and pharmacological characteristics, they have attracted the attention of many medicinal chemists. α-Aminophosphonates are known to exhibit antiviral, antitumor, antimicrobial, antioxidant and antibacterial activities, which can all be important in pathological dermatological conditions. However, their ADMET properties are not well studied. The aim of the current study was to provide preliminary information about the skin penetration of three preselected α-aminophosphonates when applying them as topical cream formulations in static and dynamic diffusion chambers. The results indicate that aminophosphonate 1a, without any substituent in the para position, shows the best release from the formulation and the highest absorption through the excised skin. However, based on our previous study, the in vitro pharmacological potency was higher in the case of para-substituted molecules 1b and 1c. The particle size and rheological studies revealed that the 2% cream of aminophosphonate 1a was the most homogenous formulation. In conclusion, the most promising molecule was 1a, but further experiments are proposed to uncover the possible transporter interactions in the skin, optimize the topical formulations and improve PK/PD profiles in case of transdermal delivery.

“…Among the disadvantages are the frequently occurring artifacts in the penetration depth profiles of an unknown nature in deep areas of the SC, as well as the inability to account for the changes in the model spectra at different SC depths (caused by interaction with the surrounding environment). To date, the NMF method has been widely used worldwide and serves as the “gold standard” in determining the penetration depth profiles of topically applied formulations into the SC in vivo or ex vivo, which was shown for dimethyl sulfoxide (DMSO) [ 189 ], caffeine and quinidine [ 36 ], hydroxyethyl cellulose and hydroxypropyl methylcellulose [ 65 ], mycosporine-like amino acids and gadusol photoprotectants [ 231 ], cosmetic oils (that have not permeated the SC) [ 192 ], essential oils (that have permeated the SC) [ 232 ], urea-containing moisturizing creams [ 233 ], soap [ 234 ], silver nanoparticles [ 148 ], nano-sized lipid particles and base cream [ 35 ], niacinamide [ 235 ], nicotine [ 236 ], and carotenoids [ 237 ].…”

Section: Confocal Raman Micro-spectroscopy (Crm)mentioning

confidence: 99%

“…Invasive methods always involve taking a skin biopsy. The “Franz diffusion cell” [ 36 , 37 , 38 ], “skin-PAMPA” (skin parallel artificial membrane permeability assay) [ 39 , 40 , 41 ], and “multi in vitro organ” [ 42 ] methods can be used, in addition to conventional histology, for in vitro and ex vivo studies of penetration using artificial membranes, skin models, or skin biopsies [ 43 ]. Target substances can be determined using the methods described above for the low-invasive analysis.…”

Section: Introductionmentioning

confidence: 99%

Optical Methods for Non-Invasive Determination of Skin Penetration: Current Trends, Advances, Possibilities, Prospects, and Translation into In Vivo Human Studies

Darvin

2023

Information on the penetration depth, pathways, metabolization, storage of vehicles, active pharmaceutical ingredients (APIs), and functional cosmetic ingredients (FCIs) of topically applied formulations or contaminants (substances) in skin is of great importance for understanding their interaction with skin targets, treatment efficacy, and risk assessment—a challenging task in dermatology, cosmetology, and pharmacy. Non-invasive methods for the qualitative and quantitative visualization of substances in skin in vivo are favored and limited to optical imaging and spectroscopic methods such as fluorescence/reflectance confocal laser scanning microscopy (CLSM); two-photon tomography (2PT) combined with autofluorescence (2PT-AF), fluorescence lifetime imaging (2PT-FLIM), second-harmonic generation (SHG), coherent anti-Stokes Raman scattering (CARS), and reflectance confocal microscopy (2PT-RCM); three-photon tomography (3PT); confocal Raman micro-spectroscopy (CRM); surface-enhanced Raman scattering (SERS) micro-spectroscopy; stimulated Raman scattering (SRS) microscopy; and optical coherence tomography (OCT). This review summarizes the state of the art in the use of the CLSM, 2PT, 3PT, CRM, SERS, SRS, and OCT optical methods to study skin penetration in vivo non-invasively (302 references). The advantages, limitations, possibilities, and prospects of the reviewed optical methods are comprehensively discussed. The ex vivo studies discussed are potentially translatable into in vivo measurements. The requirements for the optical properties of substances to determine their penetration into skin by certain methods are highlighted.