A modern approach for controlled transdermal delivery of diflunisal: optimization and in vivo evaluation

Advancements in the Transdermal Drug Delivery Systems Utilizing Microemulsion-based Gels

Microemulsion gel, as a promising transdermal nanoparticle delivery system, addresses the limitations of microemulsions and enhances their performance in drug delivery and release. This article aims to discuss the advantages of microemulsion gel, including improved drug bioavailability, reduced drug irritation, enhanced drug penetration and skin adhesion, and increased antimicrobial properties. It explores the methods for selecting microemulsion formulations and the general processes of microemulsion preparation, as well as commonly used oil phases, surfactants, and co-surfactants. Additionally, the biomedical applications of microemulsion gel in treating conditions, such as acne and psoriasis, are also discussed. Overall, this article elucidates the significant potential of microemulsion gel in topical drug delivery, providing insights into future development and clinical applications.

Diflunisal Targeted Delivery Systems: A Review

Diflunisal is a well-known drug for the treatment of rheumatoid arthritis, osteoarthritis, primary dysmenorrhea, and colon cancer. This molecule belongs to the group of nonsteroidal anti-inflammatory drugs (NSAID) and thus possesses serious side effects such as cardiovascular diseases risk development, renal injury, and hepatic reactions. The last clinical data demonstrated that diflunisal is one of the recognized drugs for the treatment of cardiac amyloidosis and possesses a survival benefit similar to that of clinically approved tafamidis. Diflunisal stabilizes the transthyretin (TTR) tetramer and prevents the misfolding of monomers and dimers from forming amyloid deposits in the heart. To avoid serious side effects of diflunisal, the various delivery systems have been developed. In the present review, attention is given to the recent development of diflunisal-loaded delivery systems, its technology, release profiles, and effectiveness.

Nanoemulgel, an Innovative Carrier for Diflunisal Topical Delivery with Profound Anti-Inflammatory Effect: in vitro and in vivo Evaluation

Purpose

Rheumatoid arthritis is an autoimmune disorder that directly affects joints. However, other body organs including heart, eyes, skin, blood vessels and lungs may also be affected. The purpose of this study was to design and evaluate a nanoemulgel formulation of diflunisal (DIF) and solubility enhanced diflunisal (DIF-IC) for enhanced topical anti-inflammatory activity.

Methodology

Nanoemulsion formulations of both DIF and DIF-IC were prepared and incorporated in three different gelling agents, namely carboxymethylcellulose sodium (CMC-Na), sodium alginate (Na-ALG) and xanthan gum (XG). All the formulations were evaluated in term of particle size, pH, conductivity, viscosity, zeta potential and in vitro drug release. The formulation 2 (NE2) of both DIF and DIF-IC which expressed optimum release and satisfactory physicochemical properties was incorporated with gelling agents to produce final nanoemulgel formulations. The optimized nanoemulgel formulation was subjected to three different in vivo anti-inflammatory models including carrageenan-induced paw edema model, histamine-induced paw edema model and formalin-induced paw edema model.

Results

DIF-IC-loaded nanoemulgel formulations yielded significantly enhanced in vitro skin permeation than DIF-loaded nanoemulgel. The nanoemulgel formulation of DIF-IC formulated with XG produced improved in vivo anti-inflammatory activity.

Conclusion

It was recommended that DIF-IC-based nanoemulgel formulation prepared with XG could be a better option for effective topical treatment of inflammatory conditions.

Flutamide-Loaded Zein Nanocapsule Hydrogel, a Promising Dermal Delivery System for Pilosebaceous Unit Disorders

Zein is a naturally occurring corn protein having similarity to skin keratin. Owing to its hydrophobicity and biodegradability, zein nanocarriers are promising drug delivery vehicles for hydrophobic dermatological drugs. In this study, zein-based nanocapsules (ZNCs) were exploited for the first time as dermal delivery carriers for flutamide (FLT), an antiandrogen used for the management of pilosebasceous unit disorders. FLT-loaded ZNC of appropriate particle size and negative surface charge were prepared by nanoprecipitation method. The dermal permeation and skin retention of FLT from ZNCs were studied in comparison to corresponding nanoemulsion (NE) and hydroalcoholic drug solution (HA). ZNCs showed a significantly lower permeation flux compared to NE and HA while increasing the skin retention of FLT. Confocal laser scanning microscopy (CLSM) demonstrated the follicular localization of the fluorescently labeled NCs. The incorporation of NCs in chitosan gel or Carbomer® 934 gel was studied. Carbomer® gel increased the skin retention of FLT compared to chitosan gel. Accordingly, Carbomer® hydrogel embedding FLT-loaded ZNCs is a promising inexpensive, biocompatible dermal delivery nanocarrier for localized therapy of PSU disorders suitable for application on oily skin.

Mechanistic Analysis of Human Skin Distribution and Follicular Targeting of Adapalene-Loaded Biodegradable Nanospheres With an Insight Into Hydrogel Matrix Influence, In Vitro Skin Irritation, and In Vivo Tolerability

This work aimed at the development of a biocompatible, non-oily nanomedicine for follicular delivery of adapalene (AD) ameliorating its irritation potential for convenient localized topical treatment of acne vulgaris. AD was efficiently incorporated into poly-ε-caprolactone nanospheres (NS) with an encapsulation efficiency of 84.73% ± 1.52%, a particle size of 107.5 ± 8.19 nm, and zeta potential of -13.1 mV demonstrating a sustained-release behavior. The AD-NS were embedded in either hydroxypropyl methylcellulose (HPMC) or hyaluronate (HA) gel. The ex vivo human skin dermatokinetics of AD from each system was studied. The nanoparticles dispersion showed significantly higher AD retention in the epidermis and dermis than AD suspension. NS-HPMC decreased whereas NS-HA increased AD retained in all the skin layers. The fate of the NS and the role of the hydrogel in modulating skin distribution was evaluated by confocal laser scanning microscopy (CLSM) imaging of fluorescently labeled NS. CLSM illustrated follicular localization of the florescent NS. HPMC gel restricted the presence of NS to the stratum corneum and epidermis. HA gel enhanced the penetration of NS to all the skin layers. In vitro skin irritation using human dermal fibroblasts and in vivo animal tolerability studies were performed. Accordingly, HA gel-dispersed AD-NS presented a nonirritant compromised cosmeceutical formulation suitable for oily acneic skin.

Combined application of mixture experimental design and artificial neural networks in the solid dispersion development

This study for the first time demonstrates combined application of mixture experimental design and artificial neural networks (ANNs) in the solid dispersions (SDs) development. Ternary carbamazepine-Soluplus®-poloxamer 188 SDs were prepared by solvent casting method to improve carbamazepine dissolution rate. The influence of the composition of prepared SDs on carbamazepine dissolution rate was evaluated using d-optimal mixture experimental design and multilayer perceptron ANNs. Physicochemical characterization proved the presence of the most stable carbamazepine polymorph III within the SD matrix. Ternary carbamazepine-Soluplus®-poloxamer 188 SDs significantly improved carbamazepine dissolution rate compared to pure drug. Models developed by ANNs and mixture experimental design well described the relationship between proportions of SD components and percentage of carbamazepine released after 10 (Q10) and 20 (Q20) min, wherein ANN model exhibit better predictability on test data set. Proportions of carbamazepine and poloxamer 188 exhibited the highest influence on carbamazepine release rate. The highest carbamazepine release rate was observed for SDs with the lowest proportions of carbamazepine and the highest proportions of poloxamer 188. ANNs and mixture experimental design can be used as powerful data modeling tools in the systematic development of SDs. Taking into account advantages and disadvantages of both techniques, their combined application should be encouraged.