Development of mucoadhesive thio-carboxymethyl cellulose for application in buccal delivery of drugs

Thiolated Cellulose: A Dual-Acting Mucoadhesive and Permeation-Enhancing Polymer

This study aims to design an anionic, thiolated cellulose derivative and to evaluate its mucoadhesive and permeation-enhancing properties utilizing enoxaparin as a model drug. 2-Mercaptosuccinic acid-modified cellulose (cellulose-mercaptosuccinate) was synthesized by the reaction of cellulose with S-acetylmercaptosuccinic anhydride. The chemical structure of the target compound was confirmed by FTIR and 1H NMR spectroscopy. The thiol content was determined by Ellman's test. The conjugate exhibited 215.5 ± 25 μmol/g of thiol groups and 84 ± 16 μmol/g of disulfide bonds. Because of thiolation, mucoadhesion on porcine intestinal mucosa was 9.6-fold enhanced. The apparent permeability (Papp) of the model dye Lucifer yellow was up to 2.2-fold improved by 0.5% cellulose-mercaptosuccinate on a Caco-2 cell monolayer. Enoxaparin permeation through rat intestinal mucosa increased 2.4-fold in the presence of 0.5% cellulose-mercaptosuccinate compared with the drug in buffer only. In vivo studies in rats showed an oral bioavailability of 8.98% using cellulose-mercaptosuccinate, which was 12.5-fold higher than that of the aqueous solution of the drug. Results of this study show that the modification of cellulose with 2-mercaptosuccinic acid provides mucoadhesive and permeation-enhancing properties, making this thiolated polymer an attractive excipient for oral drug delivery.

Evaluation of cellulose based films comprising tea tree oil against dermatophytes and yeasts

BACKGROUND

Onychomycosis is defined as infection caused by nondermatophytic molds and yeasts: tinea unguium is caused by dermatophytes.

PURPOSE

Within this study, hydroxyethyl cellulose (HEC) as an important non-ionic, water-soluble cellulose derivative was chosen to develop formulations containing tea tree oil as active antifungal agent were developed and evaluated for their potential in the treatment of onychomycosis.

METHODS

Two polymeric films based on HEC (HEC-B-04 and HEC-E-10) were obtained by solvent evaporation method and characterized in terms of appearance, disintegration, stickiness, elongation, rheological behavior and adhesiveness. Moreover, different strains of dermatophytes such as Trichophyton rubrum and yeasts as Candida albicans were treated with polymeric films containing tea tree oil (0.5 - 2 % v/v) in order to determine their antifungal potential by the inhibition zone assay.

RESULTS

HEC-B-04 and HEC-E-10 were investigated by SEM measurements resulting in confluent surface morphology. HEC-B-04 and HEC-E-10 showed disintegration after 32.7 min and 34.0 min, respectively. Furthermore, HEC-E-10 revealed a moisture index of 1.74 and underpinned adhesive properties in terms of required detachment force with 4.86 N. HEC-E-10 pointed to the most antifungal one among the others against Trichophyton rubrum and Candida albicans.

CONCLUSION

Taking these findings in consideration, promising adhesive onychial formulations were developed as forthcoming approach in treatment of nail infections.

Development of mucoadhesive modified kappa-carrageenan/pectin patches for controlled delivery of drug in the buccal cavity

In this study, modified kappa-carrageenan/pectin hydrogel patches were fabricated for treatment of buccal fungal infections. For this purpose, kappa-carrageenan-g-acrylic acid was modified with different thiolated agents (L-cysteine and 3-mercaptopropionic acid), and the thiol content of the resulting modified kappa-carrageenan was confirmed by elemental analyzer. Then, the hydrogel patches were fabricated, and characterized by Fourier-transform infrared spectroscopy, thermogravimetric analysis, ex vivo mucoadhesion test, and swelling behavior. Triamcinolone acetonide was added either directly or by encapsulating within the poly(lactic-co-glycolic acid) nanoparticles. The release amount of the drug from the directly loaded patch was 7.81 mg/g polymer, while it was 3.28 mg/g polymer for the encapsulated patch with the same content at 7 hr. The hydrogel patches had no cytotoxicity by cell culture studies. Finally, the drug loaded hydrogel patches were demonstrated antifungal activity against Aspergillus fumigatus and Aspergillus flavus. These results provide that the novel modified kappa-carrageenan and pectin based buccal delivery system has promising antifungal property, and could have advantages compared to conventional buccal delivery systems.

Thiol- and Disulfide-Based Stimulus-Responsive Soft Materials and Self-Assembling Systems

Properties and applications of synthetic thiol- and disulfide-based materials, principally polymers, are reviewed. Emphasis is placed on soft and self-assembling materials in which interconversion of the thiol and disulfide groups initiates stimulus-responses and/or self-healing for biomedical and non-biomedical applications.

Expert design and optimization of a novel buccoadhesive blend film impregnated with metformin nanoparticles

Aim: The purpose of this study was to design a metformin nanoparticles (NPs)-loaded buccoadhesive film for enhanced drug bioavailability. Materials & methods: The NPs were prepared and incorporated into a hydroxypropyl methylcellulose-chitosan blend film. Three levels of a three-factor, Box-Behnken design were used to evaluate the critical formulation variables. The drug permeation was also examined using sheep buccal mucosa. Results & conclusion: The results verified the formation of spherical NPs with an average size of 177.8 ± 6.42 nm and entrapment efficiency of 78.03 ± 0.23%. The optimum conditions for nanofilms were predicted to be: hydroxypropyl methylcellulose (700 mg), glycerol (50 mg) and chitosan (0.15 %w/v). The nanofilm showed a high drug permeation within 6 h. The metformin nanofilm offers an excellent opportunity for buccal drug delivery.

Soybean hulls: Optimization of the pulping and bleaching processes and carboxymethyl cellulose synthesis

Soybean hulls, a co-product generated in high volumes, were used to obtain pulp and CMC. The pulping process was optimized with the aid of 1%, 2%, and 2.5% NaOH solutions at 90 °C for 2 h. A 22 central composite design was used in order to optimize the bleaching process and the CMC synthesis. Volumes of bleaching solution (VS) of between 55 and 65 mL/g at temperatures between 85 and 95 °C and VS of 70 and 75 mL/g at 95 °C were applied in the pulp bleaching process. The factors considered in the carboxymethylation were the chloroacetic acid mass (1.2-2.1 g/g) and the reaction time (192-228 min), at 63 °C. The soybean hulls contain 40.62% of cellulose and have a low lignin content. The pulping process was optimized when 1% NaOH was used at 90 °C/2 h and bleaching process applying VS = 75 mL at 95 °C/4 h. The pulps showed low lignin content (<6%) and the cellulose had a high degree of crystallinity. The SEM, 1H NMR, XRD, FTIR and TGA/DTG analysis results demonstrated that it is possible to synthesize CMC (DS = 1.45) by acetylating the bleached pulp with 2.1 g of chloroacetic acid for 192 min, at 63 °C.

Thiolated polymers: Bioinspired polymers utilizing one of the most important bridging structures in nature

Thiolated polymers designated "thiomers" are obtained by covalent attachment of thiol functionalities on the polymeric backbone of polymers. In 1998 these polymers were first described as mucoadhesive and in situ gelling compounds forming disulfide bonds with cysteine-rich substructures of mucus glycoproteins and crosslinking through inter- and intrachain disulfide bond formation. In the following, it was shown that thiomers are able to form disulfides with keratins and membrane-associated proteins exhibiting also cysteine-rich substructures. Furthermore, permeation enhancing, enzyme inhibiting and efflux pump inhibiting properties were demonstrated. Because of these capabilities thiomers are promising tools for drug delivery guaranteeing a strongly prolonged residence time as well as sustained release on mucosal membranes. Apart from that, thiomers are used as drugs per se. In particular, for treatment of dry eye syndrome various thiolated polymers are in development and a first product has already reached the market. Within this review an overview about the thiomer-technology and its potential for different applications is provided discussing especially the outcome of studies in non-rodent animal models and that of numerous clinical trials. Moreover, an overview on product developments is given.

Carbohydrate-based nanomaterials for biomedical applications

Carbohydrates are abundant biomolecules, with a strong tendency to form supramolecular networks. A host of carbohydrate-based nanomaterials have been exploited for biomedical applications. These structures are based on simple mono- or disaccharides, as well as on complex, polymeric systems. Chemical modifications serve to tune the shapes and properties of these materials. In particular, carbohydrate-based nanoparticles and nanogels were used for drug delivery, imaging, and tissue engineering applications. Due to the reversible nature of the assembly, often based on a combination of hydrogen bonding and hydrophobic interactions, carbohydrate-based materials are valuable substrates for the creations of responsive systems. Herein, we review the current research on carbohydrate-based nanomaterials, with a particular focus on carbohydrate assembly. We will discuss how these systems are formed and how their properties are tuned. Particular emphasis will be placed on the use of carbohydrates for biomedical applications. This article is categorized under: Nanotechnology Approaches to Biology > Nanoscale Systems in Biology.

Buccal adhesive films with moisturizer- the next level for dry mouth syndrome?

This study was undertaken to prepare films by solvent evaporation method comprising well-known polymers in order to investigate their potential for buccal suitability. Mucoadhesive films were manufactured using different polymers such as ethyl cellulose, hydroxyethyl cellulose, hydroxypropyl methylcellulose as well as carboxymethyl cellulose. Buccal films were evaluated in regards of mucoadhesiveness, swelling and physico-chemical properties. Furthermore rheological measurement and adhesion study were carried out on the buccal porcine mucosa. Moreover, allantoin as humectant was incorporated and trans-mucosal water loss was determined. The results showed that physico-chemical, buccal adhesive and swelling properties varied depending on the composition of the polymers. The findings indicated films containing allantoin to be suitable for buccal application. In completion, adhesive films are appropriate and promising formulations in the treatment of various disease in the intraoral cavity.

A Polymer Chemistry Point of View on Mucoadhesion and Mucopenetration

Although oral is the preferred route of administration of pharmaceutical formulations, the long-standing challenge for medically active compounds to efficiently cross the mucus layer barrier limits its wider applicability. Efforts in nanomedicine to overcome this hurdle consider mucoadhesive and mucopenetrating drug carriers by selectively designing (macromolecular) building blocks. This review highlights and critically discusses recent strategies developed in this context including poly(ethylene glycol)-based modifications, cationic and thiolated polymers, as well as particles with high charge density, zeta-potential shifting ability, or mucolytic properties. The latest advances in ex vivo test platforms are also reviewed.

Preparation and evaluation of a novel dosage form for onychomycosis

Onychomycosis is a common infection of the nail caused by dermatophyte affecting mostly toenails in adults being associated with limited treatment options. In this study novel dosage forms were prepared and evaluated for their suitability in treatment of onychomycosis. Films were prepared comprising polymeric excipients such as chitosan, (hydroxypropyl)methyl cellulose, hydroxyethyl-cellulose, carboxymethylcellulose according to solvent evaporation method. Developed formulations were evaluated in terms of physical appearance, stability and adhesiveness. Furthermore skin and nail irritation studies were conducted. Five potential formulations (F1-F5) were designed while F1 and F4 exhibited the most promising results in terms of stability with 26min and 40.67min, respectively, and suitability in nail application. F1 as the most favorable dosage form revealed with 2.9438kg/m/s in terms of adhesive force the most adhesive properties in contrast to the other preparations. All formulations were found to be non-skin irritating and safe to use. Taken together, these findings suggest novel designed films containing polymeric excipients as a fruitful platform for the treatment in onychomycosis.