New transdermal bioadhesive film containing oxybutynin: In vitro permeation across rabbit ear skin

Novel Insight into Potential Leishmanicidal Activities of Transdermal Patches of Nigella Sativa: Formulation Development, Physical Characterizations, and In vitro/In vivo Assays

Cutaneous Leishmaniasis (CL) is the most common type of Leishmaniasis, which annually affects 1.5 million people worldwide. About 90% of cases are reported from countries such as Iran, Afghanistan, Pakistan, Iraq, and Saudi Arabia. The purpose of the present study was to fabricate transdermal patches of Nigella sativa (NS), characterize, and to check its in vitro/in vivo anti-Lieshmanial activity. Hydroalcoholic extract was analyzed for preliminary phytochemicals. Five formulations of transdermal patches (NS1, NS2, NS3, NS4, and NS5) were prepared by solvent evaporation method. The optimized formulation NS5 was characterized for Fourier transform-infrared spectroscopy (FTIR), smoothness, brittleness, clarity, thickness, folding endurance, uniformity of weight, percent moisture content, in vitro drug release, release kinetics, ex vivo drug permeation, and in vitro anti-Lieshmanial activity. In vivo anti-Lieshmanial activity was assessed in 30 patients (n = 30) suffering from CL. The FTIR studies showed no incompatibility among the active extract and polymers. In vitro anti-Lieshmanial assay was 194.6% ± 1.88% as compared with standard drug (p > 0.05) and in vivo anti-Lieshmanial activity was 75%. The drug release after 24 h was 87.0% ± 0.94% in NS5, which showed non-Fickian diffusion mechanism while drug permeation across rabbit skin after 24 h was up to 80.0% ± 0.91%. The results concluded that problems related to the parenteral medications used for Lieshmanial treatment can be managed by applying extract of NS seeds in the form of transdermal patch.

Film-Forming Systems for Dermal Drug Delivery

Film-forming formulations represent a novel form of sustained release dermatic products. They are applied to the skin as a liquid or semi-solid preparation. By evaporation of the volatile solvent on the skin, the polymer contained in the formulation forms a solid film. Various film-forming formulations were tested for their water and abrasion resistance and compared with conventional semi-solid formulations. Penetration and permeation studies of the formulations indicate a potential utility as transdermal therapeutic systems. They can be used as an alternative to patch systems to administer a variety of drugs in a topical way and may provide sustained release characteristics.

Drug Delivery Approaches for Managing Overactive Bladder (OAB): A Systematic Review

Overactive bladder syndrome (OAB) is characterised by urgency symptoms, with or without urgency incontinence, usually with frequency and nocturia and severely affects the quality of life. This systematic review evaluates the various drug delivery strategies used in practice to manage OAB. Advanced drug delivery strategies alongside traditional strategies were comprehensively analysed and comparatively evaluated. The present review was conducted according to the preferred reporting items for systematic reviews and meta-analyses guidelines. A total of 24 studies reporting the development of novel formulations for the treatment of OAB were considered eligible and were further categorised according to the route of drug administration. The review found that various drug delivery routes (transdermal, intravesicular, oral, vaginal and intramuscular) are used for the administration of drugs for managing OAB, however, the outcomes illustrated the marked potential of transdermal drug delivery route. The findings of the current review are expected to be helpful for pharmaceutical scientists to better comprehend the existing literature and challenges and is anticipated to provide a basis for designing and fabricating novel drug delivery systems to manage OAB.

Poly(dimethylsiloxane): A Sustainable Human Skin Alternative for Transdermal Drug Delivery Prediction

Despite the advantages of transdermal drug delivery (TDD), which makes it a fast-growing area of research in pharmaceutics, numerous challenges affect their development, which limits exploring the full potential of this alternate drug delivery route. In trying to address one of these problems, it is strongly believed that the need for a sustainable skin alternative is paramount. Efforts made in an attempt to provide a sustainable alternative to employing skin in pharmaceutical analysis, by better utilising a polymer membrane, namely poly(dimethylsiloxane), also known as PDMS are discussed. Several combined properties of this polymer, which includes its relative stability in comparison with human skin, make it a good candidate for the replacement of skin. Modifications undertaken to this polymer membrane (to create an enhanced skin mimic for permeation analysis) are discussed and reviewed in this paper, including the improved ability to predict permeability for both hydrophobic and hydrophilic drugs. Optimisations related to studying TDD including limitations encountered are also documented and reviewed. It is hoped that such developments in this field will ultimately lead to researchers replacing skin with optimised polymer-based alternatives to predict transdermal drug delivery.

Development of a Transdermal Delivery System for Tenofovir Alafenamide, a Prodrug of Tenofovir with Potent Antiviral Activity Against HIV and HBV

Tenofovir alafenamide (TAF) is an effective nucleotide reverse transcriptase inhibitor that is used in the treatment of HIV-1 and HBV. Currently, it is being investigated for HIV prophylaxis. Oral TAF regimens require daily intake, which hampers adherence and increases the possibility of viral resistance. Long-acting formulations would significantly reduce this problem. Therefore, the aim of this study was to develop a transdermal patch containing TAF and investigate its performance in vitro through human epidermis. Two types of TAF patches were manufactured. Transparent patches were prepared using acrylate adhesive (DURO-TAK 87-2516), and suspension patches were prepared using silicone (BIO-PSA 7-4301) and polyisobutylene (DURO-TAK 87-6908) adhesives. In vitro permeation studies were performed while using vertical Franz diffusion cells for seven days. An optimized silicone-based patch was characterized for its adhesive properties and tested for skin irritation. The acrylate-based patches, comprising 2% w/w TAF and a combination of chemical enhancers, showed a maximum flux of 0.60 ± 0.09 µg/cm²/h. However, the silicone-based patch comprising of 15% w/w TAF showed the highest permeation (7.24 ± 0.47 μg/cm²/h). This study demonstrates the feasibility of developing silicone-based transdermal patches that can deliver a therapeutically relevant dose of TAF for the control of HIV and HBV infections.

Semisynthetic Derivative of Artemisia annua-Loaded Transdermal Bioadhesive for the Treatment of Uncomplicated Malaria Caused by Plasmodium falciparum in Children

According to the most recent World Health Organization statistics, malaria infected approximately 219 million people in 2017, with an estimate of 435,000 deaths (World Health Organization, 2018). Communities isolated from cities are the most deprived of access to the necessary hospital facilities. Herein we report the development of a transdermal bioadhesive containing artemether (ART), an alternative, potentially lifesaving, treatment regimen for malaria in low-resource settings. Bioadhesives were prepared from an aqueous blend of hydroxyethylcellulose (4.5% w/w), ART, propoxylated-ethoxylated-cetyl-alcohol, polysorbate 80, propyleneglycol, glycerine, mineral oil, and oleic acid. In this study, the average pore size of bioadhesive 5.5b was 52.6 ± 15.31 μm. Differential scanning calorimetry and thermogravimetric analyses confirm the thermal stability of ART bioadhesives at room temperature. Tensile tests indicated good mechanical properties for bioadhesive 5.5b, when compared to 5.5a, where 5.5b showed elastic modulus 0.19 MPa, elongation at break 204%, tensile stress 0.31 MPa, tensile strength at break 0.23 MPa. Bioadhesion assays suggested that formulations containing surfactants had higher detachment forces. Permeation studies demonstrated that the best outcome was achieved with a bioadhesive containing 25 mg ART (5.5b) that after 24 h released 6971 ± 125 μg, which represents approximately 28% of drug permeation. Data reported presents a promising candidate for a new antimalarial transdermal formulation.

Transepidermal water loss and skin conductance as barrier integrity tests

In vitro skin permeation studies are commonly used in the risk assessment of toxic compound skin exposure. The present study examined the utility of transepidermal water loss (TEWL) and electrical conductance as barrier integrity tests before skin permeation studies in vitro using a large number of skin samples and fentanyl. TEWL and conductance of the skin samples were measured before the permeation experiments in Franz diffusion cells in vitro with a vapometer and low voltage application, respectively. The data were analyzed based on the in vitro permeation results and in vivo skin absorption information from the transdermal fentanyl product labels. The results showed poor correlations between TEWL and electrical conductance for the skin samples. Weak correlations between fentanyl delivery rate (flux x area) and TEWL and skin conductance were observed. For comparison, TEWL and conductance were also examined after skin perturbation with a syringe needle, and both TEWL and conductance values of the skin samples increased after the perturbation. The data suggest that either TEWL of 10 g/m²/h or skin conductance of 0.07 mS/cm² can be used as exclusion criteria in skin integrity testing to remove skin samples with high permeabilities under the in vitro conditions studied.

Formulation and in vitro/in vivo evaluation of chitosan-based film forming gel containing ketoprofen

The film forming gel, adhered to skin surfaces upon application and formed a film, has an advantage onto skin to provide protection and continuous drug release to the application site. This study aimed to prepare a chitosan-based film forming gel containing ketoprofen (CbFG) and to evaluate the CbFG and film from CbFG (CbFG-film). CbFG were prepared with chitosan, lactic acid and various skin permeation enhancers. The physicochemical characteristics were evaluated by texture analysis, viscometry, SEM, DSC, XRD and FT-IR. To identify the mechanism of skin permeation, in vitro skin permeation study was conducted with a Franz diffusion cell and excised SD-rat and hairless mouse dorsal skin. In vivo efficacy assessment in mono-iodoacetate (MIA)-induced rheumatoid arthritis animal model was also conducted. CbFG was successfully prepared and, after applying CbFG to the excised rat dorsal skin, the CbFG-film was also formed well. The physicochemical characteristics of CbFG and CbFG-film could be explained by the grafting of oleic acid onto chitosan in the absence of catalysts. In addition, CbFG containing oleic acid had a higher skin permeation rate in comparison with any other candidate enhancers. The in vivo efficacy study also confirmed significant anti-inflammatory and analgesic effects. Consequently, we report the successful preparation of chitosan-based film forming gel containing ketoprofen with excellent mechanical properties, skin permeation and anti-inflammatory and analgesic effects.

Bioadhesive hydrogels for cosmetic applications

INTRODUCTION

The use of bioadhesive hydrogels for skin care presents important advantages such as long residence times on the application site and reduced product administration frequency.

OBJECT

The aim of the present work was to develop bioadhesive hydrogels for skin application, using caffeine as a model active ingredient.

METHODS

Eight hydrogels were formulated using binary combinations of a primary polymer (carbomer homopolymer type C (Carbopol(®) 980) or kappa carrageenan potassium salt (Gelcarin(®) GP-812 NF)) and a secondary polymer (carbomer copolymer type B (Pemulen(™) TR-1), xanthan gum or guar gum). Hydrogels were characterized by means of physico-chemical (dynamic rheological measurements, spreadability and adhesion measurements) and sensory methods (projective mapping in combination with a check-all-that-apply (CATA) question). Caffeine hydrogels were formulated using two of the most promising formulations regarding adhesion properties and sensory characteristics. In vitro active ingredient release studies were carried out.

RESULTS

Hydrogel formulations showed a prevalently elastic rheological behaviour. Complex viscosity of carbomer homopolymer type C hydrogels was higher than that of the kappa carrageenan hydrogels. Besides, complex viscosity values were dependent on the secondary polymer present in the formulation. Significant differences among hydrogels were found in detachment force, work of adhesion and spreading diameter results. Association of projective mapping with CATA allowed to determine similarities and dissimilarities among samples. Cluster analysis associated the samples in two groups. Two hydrogels were selected to study the release of caffeine. Both hydrogels presented similar release profiles which were well described by the Higuchi model. Caffeine release was exclusively controlled by a diffusive process.

CONCLUSION

Physico-chemical and sensory techniques enabled the identification of bioadhesive hydrogel formulations with positive characteristics for cosmetic applications. Formulations which combined carbomer homopolymer type C with xanthan gum or with carbomer copolymer type B were the most promising for bioadhesive skin products. Caffeine release profiles of selected formulations were not statistically different. Both hydrogels gradually released the active ingredient, reaching approximately 80% within the first 5 h, and their profiles were well described by the Higuchi model. In this context, it could be concluded that the selected hydrogels are suitable bioadhesive hydrogel formulations for cosmetic application on the skin.

Morphological changes in the salivary acini after in vivo cholinergic stimulation

AIMS

Overactive bladder syndrome treated by muscarinic receptor antagonists may be complicated by reduced salivation. Cholinergic agonists may reverse this effect. The aim of the present study was to determine the antagonizing effect of a cholinergic agonist (carbachol) on a muscarinic receptor antagonist (oxybutynin) in the submandibular acini in a rat model.

METHODS

Forty male Sprague Dawley rats were divided into three groups: Group I (control), Group II (vehicle), and Group III (treatment). Group III was subdivided so Group IIIa was treated with a muscarinic receptor antagonist (oxybutynin) for 1 week, Group IIIb was treated with oxybutynin for 3 weeks, and Group IIIc was treated with oxybutynin for 1 week and oxybutynin and a cholinergic agonist (carbachol) for 2 weeks. Histological and ultrastructural studies were performed on submandibular glands.

RESULTS

Group IIIa showed moderate atrophic changes in the serous acini and ducts. Group IIIb showed serous acini with distorted wall, widening of the inter-lobar space, and deposition of mononuclear cells in the connective tissue. Group IIIc had serous acini similar to Group I, with mildly dilated inter-lobar ducts, but some serous acini revealed double nuclei and the inter-lobar duct showed luminal vacuolations. Ultrastructural studies confirmed histological results.

CONCLUSIONS

Muscarinic receptor antagonist administration led to changes in the submandibular gland of rats, while concomitant administration of cholinergic agonists seemed to counteract these atrophic changes. Additional studies should assess carbachol as a cholinergic agonist in treating dry mouth in patients with overactive bladder syndrome who are taking the muscarinic receptor. Neurourol. Urodynam. 35:574-581, 2016. © 2015 Wiley Periodicals, Inc.

Bioadhesive films containing benzocaine: correlation between in vitro permeation and in vivo local anesthetic effect

PURPOSE

The aim of this work was to develop anesthetic bioadhesive films containing benzocaine and study their in vitro skin permeation and in vivo performance, in comparison with commercial formulations.

METHODS

Films containing 3% and 5% w/w of benzocaine were prepared and characterized by weight, drug content, thickness and morphology. In vitro permeation assays were performed in vertical diffusion cells using full-thickness pig ear skin as barrier. Intensity and duration of analgesia were evaluated in rats by tail-flick test, and skin histological analysis was carried out.

RESULTS

Tail-flick test showed that the duration of benzocaine-induced analgesia was significantly prolonged with the films compared to commercial creams, in agreement with the higher in vitro permeation. Histological analysis of the rat tail skin did not reveal morphological tissue changes nor cell infiltration signs after application of the commercial creams or films.

CONCLUSIONS

Results from our study indicate that the films developed in this work can be considered as innovative dermal/transdermal therapeutic systems for benzocaine local delivery.

Transdermal delivery of salbutamol sulphate: formulation and evaluation

Salbutamol patches were prepared and evaluated. The effect of different Eudragits and various plasticizers on the properties of the patches were studied. Patches were prepared by casting method employing different plasticizers. These patches were evaluated for weight, thickness uniformity, swelling index, tensile strength, elongation percent and moisture absorption capacity. Release was studied. Tensile strength of the patches using Eudragit RS 100 as well as RS100 + L100 and triacetin was the lowest. Formulae containing 10% oleic acid and 5% dimethyl formamide, respectively, showed the highest permeability. These two formulae were studied clinically, the first formula only showed a significant improvement.

Physical characterization of a new skin bioadhesive film

Physical properties (roughness, gloss, mechanical, surface topography and adhesive) of a bioadhesive film for the transdermal delivery of drugs and its interactions with a skin model surface were studied. Roughness is a measurement of the small-scale variations in the height of a physical surface. No significant differences in Ra between the "x" and "y" dimensions for both the skin model and patch were detected, due to uniformity in their production. Scanning electron microscope pictures showed small particles projected from the film. Those particles resulted in increasing roughness and surface area. For the patch, gloss values measured at 20 degrees were 6.0 +/- 0.9 and at 60 degrees , 32.2 +/- 2.2 gloss units, respectively, indicating a semi-gloss material. Concerning the mechanical properties, the tensile strength of the film resulted four- to sevenfold greater than the peel force from the model skin used, indicating the suitability of the film for skin application. The adhesion to skin model depended on the amount of water used for film application and on the elapsed time between film application and removal. Finally, the model skin that was invented by Charkoudian can be used as an alternative to costly and highly variable human skin substrates since it possesses human topography.