Novel microemulsion-based gel formulation of tazarotene for therapy of acne

Formulation development of tazarotene-loaded PLGA nanoparticles for follicular delivery in the treatment of inflammatory skin diseases

Tazarotene is a widely prescribed topical retinoid for acne vulgaris and plaque psoriasis and is associated with skin irritation, dryness, flaking, and photosensitivity. In vitro permeation of tazarotene was studied across the dermatomed human and full-thickness porcine skin. The conversion of tazarotene to the active form tazarotenic acid was studied in various skin models. Tazarotene-loaded PLGA nanoparticles were prepared using the nanoprecipitation technique to target skin and hair follicles effectively. The effect of formulation and processing variables on nanoparticle properties, such as particle size and drug loading, was investigated. The optimized nanoparticle batches with particle size <500 µm were characterized further for FT-IR analysis, which indicated no interactions between tazarotene and PLGA. Scanning electron microscopy analysis showed uniform, spherical, and non-agglomerated nanoparticles. In vitro release study using a dialysis membrane indicated a sustained release of 40-70 % for different batches over 36 h, following a diffusion-based release mechanism based on the Higuchi model. In vitro permeation testing (IVPT) in full-thickness porcine skin showed significantly enhanced follicular and skin delivery from nanoparticles compared to solution. The presence of tazarotenic acid in the skin from tazarotene nanoparticles indicated the effectiveness of nanoparticle formulations in retaining bioconversion ability and targeting follicular delivery.

Sustained release gel (polymer-free) of itraconazole-loaded microemulsion for oral candidiasis treatment: time-kill kinetics and cellular uptake

Itraconazole (ICZ) was prepared in a self-microemulsifying (SM) gel. This gel was intended for use in the oral mucosa, where low volume and flow of saliva result in limited solubility and absorption of drugs that are poorly water-soluble. The drug-loaded gel formulation (ICZ-SM) was selected as a clear solution in the ternary phase diagram to improve the solubility of ICZ. Seven ratios (S1-S7) were prepared by mixing polyoxyl 35 castor oils (P35), a medium chain with a blend of mono-, di-, and triglycerides (MCT), and water. Phase separation of large-sized emulsions by countering with artificial saliva were observed in dilution tests for the formulation contained MCT, P35, and water at the ratios of 70:20:10 (S1), 10:80:10 (S3), and 20:60:20 (S4). Formulations in the ratios of 15:50:35 (S5) and 19:43:38 (S6) produced strong ICZ-SM gels, as shown by rheology tests, whereas the formulations at the ratios of 30:60:10 (S2) and 10:43:47 (S7) exhibited no elasticity. A model of zero-order kinetic (S5) and first-order kinetic (S6) were found to best fit the release kinetics of ICZ from the gels. Time-killing assays revealed that S5 and S6 required less time compared with S2 and the ICZ solution. Furthermore, S5 exhibited the highest increase in cell uptake compared with S2, S6, and the ICZ solution. These findings suggest that the ICZ-SM gel was a free polymer capable of delivering an ICZ for the treatment of oral candidiasis, and that ICZ-SM gels applied locally exhibit enhanced absorption into cells.

Tackling acne vulgaris by fabrication of tazarotene-loaded essential oil-based microemulsion: In vitro and in vivo evaluation

This study aimed to formulate and optimize an anti-acne drug namely tazarotene (TZR) in essential oil-based microemulsion (ME) using either Jasmine oil (Jas) or Jojoba oil (Joj). TZR-MEs were prepared using two experimental designs (Simplex Lattice Design®) and characterized for droplet size, polydispersity index, and viscosity. Further in vitro, ex vivo, and in vivo investigations were performed for the selected formulations. Results revealed that TZR-selected MEs exhibited suitable droplet size, homogenous dispersions, and acceptable viscosity, in addition to spherical-shaped particles in morphology. The ex vivo skin deposition study showed a significant TZR accumulation in all skin layers for the Jas-selected ME over the Joj one. Further, TZR didn't show any antimicrobial activity against P. acnes, however, it was boosted when it was incorporated into the selected MEs. The in vivo study results of the infected mice ears induced by P. acnes revealed that our selected MEs successfully reached a high level of ear thickness reduction of 67.1% and 47.4% for Jas and Joj selected MEs, respectively, versus only 4% for the market product. Finally, the findings confirmed the ability to use essential oil-based ME, particularly with Jas, as a promising carrier for topical TZR delivery in the treatment of acne vulgaris.

Preparation and Characterization of Lidocaine-Loaded, Microemulsion-Based Topical Gels

Microemulsion-based gels (MBGs) were prepared for transdermal delivery of lidocaine and evaluated for their potential for local anesthesia. Lidocaine solubility was measured in various oils, and phase diagrams were constructed to map the concentration range of oil, surfactant, cosurfactant, and water for oil-in-water (o/w) microemulsion (ME) domains, employing the water titration method at different surfactant/cosurfactant weight ratios. Refractive index, electrical conductivity, droplet size, zeta potential, pH, viscosity, and stability of fluid o/w MEs were evaluated. Carbomer^® 940 was incorporated into the fluid drug-loaded MEs as a gelling agent. Microemulsion-based gels were characterized for spreadability, pH, viscosity, and in-vitro drug release measurements, and based on the results obtained, the best MBGs were selected and subsequently subjected to ex-vivo rat skin permeation anesthetic effect and irritation studies. Data indicated the formation of nano-sized droplets of MEs ranging from 20 - 52 nm with a polydispersity of less than 0.5. In-vitro release and ex-vivo permeation studies on MBGs showed significantly higher drug release and permeation in comparison to the marketed topical gel. Developed MBG formulations demonstrated greater potential for transdermal delivery of lidocaine and advantage over the commercially available gel product, and therefore, they may be considered as potential vehicles for the topical delivery of lidocaine.

Microsponge based gel as a simple and valuable strategy for formulating and releasing Tazarotene in a controlled manner

This study aims to deliver Tazarotene (TZR) in a controlled manner to reduce adverse effects in the form of a microsponge-based gel. It adopts the methodology of a similar study by the undersigned authors with respect to the drug Clindamycin. Under both studies, the methodology used is emulsion solvent diffusion. Accordingly, we altered the concentrations of polymer and emulsifier to generate four formulations of TZR microsponges. Additionally, we used two types of emulsifiers and two types of solvents to develop two further microsponge formulations. We then studied the physical properties of each formulation, as well as drug-polymer interactions. Echoing findings from our prior study of Clindamycin, we found that microsponge formulations coded by T1 and T3 had superior production yield and entrapment efficiency, and their particle size was suitable for dermal application. As in the prior Clindamycin study, each of the T1 and T3 microsponge formulations were incorporated into a Carbopol gel and evaluated in vitro. The optimal formulation was found to be the microsponge formulation gel T8, which released 87.63% of TZR over 12 h. No significant interactions between the drug and excipients were found through Fourier transform infrared spectroscopy and differential scanning calorimetry.

Lipid liquid-crystalline nanoparticles sustained teicoplanin delivery for treatment of chronic osteomyelitis: In vitro and in vivo studies

AIM

The aim of our work is to formulate teicoplanin-loaded lipid liquid-crystalline (cubosomes) nanoparticles laden gel to sustain the release of teicoplanin for effective treatment of infected bone.

METHODS

Cubosomal gels were prepared by emulsification technique. The batches were characterized for morphology, size, entrapment efficacy, viscosity, in-vitro flux, in-vivo drug release and histopathological studies.

RESULTS

Transmission electron microscopy images confirmed the bi-continuous liquid crystalline phase. The size (61-202nm), viscosity (12,138-13,132cp), and entrapment efficacy (69.0-81.8% w/w) increase with the level of glycerol monooleate. The in-vitro flux data showed sustain teicoplanin release from the cubosomal gels for 36 days, compared to 48h from the control gel. The in-vivo teicoplanin release study (osteomyelitis induced by S. aureus) showed low serum drug-concentration from the gel (up to 14 days) compared to high-serum drug-concentration using intravenous injections.

CONCUSSION

In conclusion the study demonstrated the potential of cubosomes for effective delivery of teicoplanin to replace injections.

Novel Gel Microemulsion as Topical Drug Delivery System for Curcumin in Dermatocosmetics

Gel microemulsion combines the advantages of the microemulsion, which can encapsulate, protect and deliver large quantities of active ingredients, and the gel, which is so appreciated in the cosmetic industry. This study aimed to develop and characterize new gel microemulsions suitable for topical cosmetic applications, using grape seed oil as the oily phase, which is often employed in pharmaceuticals, especially in cosmetics. The optimized microemulsion was formulated using Tween 80 and Plurol^® Diisostearique CG as a surfactant mix and ethanol as a co-solvent. Three different water-soluble polymers were selected in order to increase the viscosity of the microemulsion: Carbopol^® 980 NF, chitosan, and sodium hyaluronate salt. All used ingredients are safe, biocompatible and biodegradable. Curcumin was chosen as a model drug. The obtained systems were physico-chemically characterized by means of electrical conductivity, dynamic light scattering, polarized microscopy and rheometric measurements. Evaluation of the cytotoxicity was accomplished by MTT assay. In the final phase of the study, the release behavior of Curcumin from the optimized microemulsion and two gel microemulsions was evaluated. Additionally, mathematical models were applied to establish the kinetic release mechanism. The obtained gel microemulsions could be effective systems for incorporation and controlled release of the hydrophobic active ingredients.

Foray into Concepts of Design and Evaluation of Microemulsions as a Modern Approach for Topical Applications in Acne Pathology

With a fascinating complexity, governed by multiple physiological processes, the skin is considered a mantle with protective functions which during lifetime are frequently impaired, triggering dermatologic disorders. As one of the most prevalent dermatologic conditions worldwide, characterized by a complex pathogenesis and a high recurrence, acne can affect the patient's quality of life. Smart topical vehicles represent a good option in the treatment of a versatile skin condition. By surpassing the stratum corneum known for diffusional resistance, a superior topical bioavailability can be obtained at the affected place. In this direction, the literature study presents microemulsions as a part of a condensed group of modern formulations. Microemulsions are appreciated for their superior profile in matters of drug delivery, especially for challenging substances with hydrophilic or lipophilic structures. Formulated as transparent and thermodynamically stable systems, using simplified methods of preparation, microemulsions have a simple and clear appearance. Their unique structures can be explained as a function of the formulation parameters which were found to be the mainstay of a targeted therapy.

Development of an Oil-in-Water Self-Emulsifying Microemulsion for Cutaneous Delivery of Rose Bengal: Investigation of Anti-Melanoma Properties

The topical delivery route is proposed as an alternative or adjunctive approach to melanoma treatment, since the target site for melanoma treatment-the epidermal basal layer-is potentially accessible by this route. Microemulsion systems are effective delivery vehicles for enhanced, targeted skin delivery. This work investigated the effect of Rose Bengal (RB) and RB-loaded self-emulsifying microemulsions (SEMEs) on growth inhibition of human melanoma and normal skin cell monolayers, the safety of the excipients incorporated in SEMEs on human cell lines, and the in-vitro human skin penetration of RB delivered in SEMEs and control solution. Cellular toxicity was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, and the growth inhibitory mechanism of RB was investigated by flow cytometry using PI staining. Unloaded SEMEs caused reduced cellular toxicity compared to the surfactant excipient, Labrasol^®. RB-loaded SEMEs increased cell growth inhibition compared to the RB aqueous solution. Flow cytometry revealed apoptotic cells after treatment with RB-loaded SEMEs, indicating that apoptosis may be one of the mechanisms of cell death. Preliminary results of multiphoton microscopy with fluorescence lifetime imaging (MPM-FLIM) analysis showed deeper penetration with greater skin concentrations of RB delivered from SEMEs compared to the RB aqueous solution. This study highlights the enhanced skin penetration and antimelanoma effects of RB loaded in a SEME system.

Targeted Topical Delivery of Retinoids in the Management of Acne Vulgaris: Current Formulations and Novel Delivery Systems

Acne vulgaris is a common inflammatory pilosebaceous condition that affects 80-90% of adolescents. Since the introduction of tretinoin over 40 years ago, topical retinoid products have been a mainstay of acne treatment. The retinoids are very effective in addressing multiple aspects of the acne pathology as they are comedolytic and anti-inflammatory, and do not contribute to antibiotic resistance or microbiome disturbance that can be associated with long-term antibiotic therapies that are a common alternative treatment. However, topical retinoids are associated with skin dryness, erythema and pain, and may exacerbate dermatitis or eczema. Thus, there is a clear need to target delivery of the retinoids to the pilosebaceous units to increase efficacy and minimise side effects in surrounding skin tissue. This paper reviews the current marketed topical retinoid products and the research that has been applied to the development of targeted topical delivery systems of retinoids for acne.

Topically applied lipid- and surfactant-based nanoparticles in the treatment of skin disorders

INTRODUCTION

In the treatment of dermatological disorders, topical drug administration is a mainstay. However, nanoparticle-based carrier systems could improve and expand the current therapeutic range via localized delivery of active ingredients. Areas covered: This review gives a detailed description of lipid- and surfactant-based drug delivery systems which have been explored for topical drug administration. To guide researchers in their choice of delivery system, an informative decision tree is included. Moreover, this review provides a complete overview of the topical or transdermal drug products, currently on the market or under clinical investigation, delivered via the discussed carriers, in the treatment of skin disorders. Expert opinion: Conventional liposomes are still popular in the domain of topical or transdermal drug delivery and dominate the market landscape. However, several other carriers, such as exosomes and niosomes, are being explored which offer distinct advantages over liposomes and should therefore not be disregarded when selecting a proper drug delivery system.