Design and development of topical liposomal formulations in a regulatory perspective

HSPiP and QbD oriented optimized stearylamine-elastic liposomes for topical delivery of ketoconazole to treat deep seated fungal infections: In vitro and ex vivo evaluations

The study explored stearylamine containing cationic elastic liposomes to improve topical delivery and efficacy of ketoconazole (KETO) to treat deeply seated fungal infections. Stearylamine was used for dual functionalities (electrostatic interaction and flexibility in lipid bilayer). Hansen solubility program (HSPiP) estimated Hansen solubility parameters (HSP) based on the SMILE file and structural properties followed by experimental solubility study to validate the predicted values. Various formulations were developed by varying phosphatidylcholine and surfactants (tween 80 and span 80) concentration. To impart cationic properties, stearylamine (1.0 %) was added into the organic phase. Using quality by design (QbD) method, we optimized the formulations and evaluated for vesicle size, polydispersity index, zeta potential, morphology (scanning electron microscopy), in vitro drug release (%), and ex vivo permeation profiles. Result showed that there is a good correlation (0.65) between HSPiP predicted and actual experimental solubility of KETO in water, chloroform, S80, and tween 80. Spherical OKEL1 showed an established correlation between the predicted and the actual formulation parameters (size, zeta potential, and polydispersity index) (259 nm vs 270 nm, +2.4 vs 0.21 mV, and 0.24 vs 0.27). OKEL1 was associated with the highest value of %EE (83.1 %) as compared to liposomes. Finally, OKEL1 exhibited the highest % cumulative permeation (49.9 %) as compared to DS (13 %) and liposomes (25 %). Moreover, OKEL1 resulted in 4-fold increase in permeation flux as compared to DS which may be attributed to vesicular mediated improved permeation and gel based compensated trans epidermal water loss in the skin. The drug deposition elicited OKEL1 and OKEL1-gel as suitable carriers for maximum therapeutic benefit to treat deeply seated fungal infections.

Sabry S, El-Nahas HM, Ayoub MM. Maximizing the Use of Ivermectin Transethosomal Cream in the Treatment of Scabies

In an effort to tackle the skin reactions frequently observed with topical application of ivermectin (IVM), a study was conducted to develop and optimize transethosomes (TESMs) loaded with IVM for scabies treatment. A three-factor, two-level (23) full factorial design was employed. Soyabean phosphatidylcholine concentration (A), ethanol concentration (B) and Span 60 amount (C) were studied as independent factors, while entrapment efficiency (EE), particle size (PS), polydispersity index (PDI), zeta potential (ZP) and drug release after 6 h (Q6h) were characterized. The skin sensitivity of the optimized formulation was evaluated by skin irritation test and histopathological examination. The EE% ranged from 88.55 ± 0.576% to 94.13 ± 0.305%, PS was from 318.033 ± 45.61 nm to 561.400 ± 45.17 nm, PDI was from 0.328 ± 0.139 to 0.671 ± 0.103, ZP was from -54.13 ± 1.09 mV to -60.50 ± 2.34 mV and Q6h was from 66.20 ± 0.30% to 93.46 ± 0.86%. The IVM-loaded transethosomal cream showed lower skin irritation and a more intact epidermal layer with intact keratinocyte, compared to the marketed cream which showed severe destruction of the keratin layer. Therefore, patient compliance can be improved by encapsulating IVM within TESMs to minimize its skin reactions.

Enhancement of Physical Appearance, Skin Permeation, and Odor Reduction Using Liposome of Hydrolyzed Salmon Collagen for Cosmetic Products

Hydrolyzed collagen (HC) derived from salmon (Oncorhynchus nerka) skin possesses properties that can nourish the skin, and it is one of the active ingredients used in cosmeceutical products for moisturizing the facial skin. However, HC solution gives off a fishy odor and it is gray in color that makes the product unacceptable for cosmetic purposes. This study aimed to use liposome-encapsulated hydrolyzed salmon collagen to improve its physical appearance, skin permeation, and eliminate the fishy odor. Two percent of HC and vitamin B3 (VitB3) were used as active ingredients to incorporate into liposomes. Phosphatidylcholine, cholesterol, and Tween 80 at a suitable weight ratio of 8 : 2 : 1 produced nano-sized vesicles (170.6 ± 0.70 nm) with the highest percentage of entrapment efficiency (95.72 ± 2.00%) of VitB3 and (49.63 ± 1.74%) of HC. Skin permeation and odor detection of the HC-VitB3 liposome were studied using Franz's diffusion cell and gas chromatography, respectively, and compared with HC-VitB3 solution. Subsequently, facial serums were formulated using HC-VitB3 liposomes and HC-VitB3 solutions, and a product satisfaction test was conducted with 100 volunteers to determine their preferred product. The results of the studies of HC-VitB3 liposome serum showed improved formulation appearance, enhanced skin permeation, and better odor elimination compared to the HC-VitB3 serum. Furthermore, seventy-three volunteers in the product satisfaction test preferred and selected the liposomal serum for its superior scent. From all the experimental results, it could be seen that liposomes can help increase skin penetration, and undesirable odors and colors can be masked by the appropriate lipid bilayer structure of liposomes.

Feeding Next-Generation Nanomedicines to Europe: Regulatory and Quality Challenges

New and innovative nanomedicines have been developed and marketed over the past half-century, revolutionizing the prognosis of many human diseases. Although a univocal regulatory definition is not yet available worldwide, the term "nanomedicines" generally identifies medicinal products that use nanotechnology in their design or production. Due to the intrinsic high structural complexity of these products, the scientific and regulatory communities are reflecting on how to revise the regulatory framework to provide a more appropriate benefit/risk balance to authorize them on the market, considering the impact of their peculiar physicochemical features in the evaluation of efficacy and safety patterns. Herein, a critical perspective is provided on the current open issues regarding regulatory qualification and physicochemical characterization of nanosystems considering the current European regulatory framework on nanomedicine products. Practicable paths for improving their quality assurance and predicting their fate in vivo are also argued. Strengthening the multilevel alliance among academic institutions, industrial stakeholders, and regulatory authorities seems strategic to support innovation by standard approaches (e.g., qualification, characterization, risk assessment), and to expand current knowledge, also benefiting from the new opportunities offered by artificial intelligence and digitization in predictive modelling of the impact of nanomedicine characteristics on their fate in vivo.

Advance and Challenges in the Treatment of Skin Diseases with the Transdermal Drug Delivery System

Skin diseases are among the most prevalent non-fatal conditions worldwide. The transdermal drug delivery system (TDDS) has emerged as a promising approach for treating skin diseases, owing to its numerous advantages such as high bioavailability, low systemic toxicity, and improved patient compliance. However, the effectiveness of the TDDS is hindered by several factors, including the barrier properties of the stratum corneum, the nature of the drug and carrier, and delivery conditions. In this paper, we provide an overview of the development of the TDDS from first-generation to fourth-generation systems, highlighting the characteristics of each carrier in terms of mechanism composition, penetration method, mechanism of action, and recent preclinical studies. We further investigated the significant challenges encountered in the development of the TDDS and the crucial significance of clinical trials.

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

Several ex vivo and in vitro skin models are available in the toolbox of dermatological and cosmetic research. Some of them are widely used in drug penetration testing. The excised skins show higher variability, while the in vitro skins provide more reproducible data. The aim of the current study was to compare the chemical composition of different skin models (excised rat skin, excised human skin and human-reconstructed epidermis) by measurement of ceramides, cholesterol, lactate, urea, protein and water at different depths of the tissues. The second goal was to compile a testing system, which includes a skin-on-a-chip diffusion setup and a confocal Raman spectroscopy for testing drug diffusion across the skin barrier and accumulation in the tissue models. A hydrophilic drug caffeine and the P-glycoprotein substrate quinidine were used in the study as topical cream formulations. The results indicate that although the transdermal diffusion of quinidine is lower, the skin accumulation was comparable for the two drugs. The various skin models showed different chemical compositions. The human skin was abundant in ceramides and cholesterol, while the reconstructed skin contained less water and more urea and protein. Based on these results, it can be concluded that skin-on-a-chip and confocal Raman microspectroscopy are suitable for testing drug penetration and distribution at different skin layers within an exposition window. Furthermore, obese human skin should be treated with caution for skin absorption testing due to its unbalanced composition.

Novel Pharmaceutical Strategies for Enhancing Skin Penetration of Biomacromolecules

Skin delivery of biomacromolecules holds great advantages in the systemic and local treatment of multiple diseases. However, the densely packed stratum corneum and the tight junctions between keratinocytes stand as formidable skin barriers against the penetration of most drug molecules. The large molecular weight, high hydrophilicity, and lability nature of biomacromolecules pose further challenges to their skin penetration. Recently, novel penetration enhancers, nano vesicles, and microneedles have emerged as efficient strategies to deliver biomacromolecules deep into the skin to exert their therapeutic action. This paper reviews the potential application and mechanisms of novel skin delivery strategies with emphasis on the pharmaceutical formulations.

Use of Retinoids in Topical Antiaging Treatments: A Focused Review of Clinical Evidence for Conventional and Nanoformulations

Nowadays, numerous skincare routines are used to rejuvenate aging skin. Retinoids are one of the most popular ingredients used in antiaging treatments. Among the representatives of retinoids, tretinoin is considered the most effective agent with proven antiaging effects on the skin and can be found in formulations approved as medicines for topical treatment of acne, facial wrinkles, and hyperpigmentation. Other retinoids present in topical medicines are used for various indications, but only tazarotene is also approved as adjunctive agent for treatment of facial fine wrinkling and pigmentation. The most commonly used retinoids such as retinol, retinaldehyde, and retinyl palmitate are contained in cosmeceuticals regulated as cosmetics. Since clinical efficacy studies are not required for marketing cosmetic formulations, there are concerns about the efficacy of these retinoids. From a formulation perspective, retinoids pose a challenge to researchers as a result of their proven instability, low penetration, and potential for skin irritation. Therefore, novel delivery systems based on nanotechnology are being developed to overcome the limitations of conventional formulations and improve user compliance. In this review, the clinical evidence for retinoids in conventional and nanoformulations for topical antiaging treatments was evaluated. In addition, an overview of the comparison clinical trials between tretinoin and other retinoids is presented. In general, there is a lack of evidence from properly designed clinical trials to support the claimed efficacy of the most commonly used retinoids as antiaging agents in cosmeceuticals. Of the other retinoids contained in medicines, tazarotene and adapalene have clinically evaluated antiaging effects compared to tretinoin and may be considered as potential alternatives for antiaging treatments. The promising potential of retinoid nanoformulations requires a more comprehensive evaluation with additional studies to support the preliminary findings.