Bioadhesive film formed from a novel organic-inorganic hybrid gel for transdermal drug delivery system

Dissolvable Topical Formulations for Burst and Constant Delivery of Vitamin C

Healthy skin has a high vitamin C concentration that protects against ultraviolet (UV)-induced damage, promotes wound healing, and lowers cancer risk. The present contribution describes two drug delivery systems for topical administration of vitamin C. The electrospun poly(vinyl alcohol) (PVA) nanofiber carrier of vitamin C exhibits a burst release profile (66 mg/g/h followed by 6.3 mg/g/h). In comparison, a new composite PVA nanofiber-molecular capsule delivers vitamin C at a constant rate (8.2 mg/g/h) with a zeroth-order release profile for better therapeutic management. Both delivery systems protect vitamin C and afford increased heat stability. The molecular capsules of β-cyclodextrin with the vitamin C inclusion complex are immobilized on cellulose acetate and electrosprayed onto an electrospun PVA nanofiber mat.

Fabricating transdermal film formulations of montelukast sodium with improved chemical stability and extended drug release

Montelukast Sodium (MK) is a leukotriene receptor antagonist, an oral drug generally prescribed to control chronic asthma symptoms. This research aims to provide the transdermal delivery of this drug in a controlled release profile as a better mode of drug delivery, specifically for the pediatric and elderly population. Transdermal delivery of the drug not only improves the drug's bioavailability but also maintains the concentration of the drug in the plasma without increasing the frequency of the drug dosage. Transdermal film formulations were developed using sodium alginate (SA) and lignosulphonic acid (LS) as the matrix and PEG-400 or Glycerine (Gly) as the plasticizers. Various physiochemical characteristic evaluations of the formulated films were conducted, revealing that the formulation with Glycerine as the plasticizer had a smooth surface and was flexible. It was observed that this formulation had the highest moisture uptake capacity and the lowest moisture loss capacity when compared with the other two formulations. It was also observed that the barium chloride cross-linked formulation had a higher swelling index when compared with calcium chloride cross-linked films. The surface pH of all the formulations was monitored to be around 7.5. In the in vitro release studies, the cross-linked films showed a controlled release over 36 h compared with the non-cross-linked films. Based on the observations and results, the cross-linked film formulation showed a better-controlled release of the drug and could potentially increase its bioavailability. TGA analysis of the polymeric mixture demonstrated the thermal stability of the SA blends, which enhanced the flexibility of the SALS blend with Glycerine. XRD of samples confirmed the amorphous nature of SALS blends with Gly, which influences the flexibility of the blend. The blends are further investigated for morphology using SEM to test their compatibility with the drug.

Nitrocellulose Based Film-Forming Gels with Cinnamon Essential Oil for Covering Surface Wounds

Acute and chronic wounds caused by assorted reasons impact patient's quality of life. Films are one of the main types of moisture retentive dressings for wounds. To improve the healing of the wound, films must ensure there is no microorganism contamination, protect from negative environmental effects, and support optimal moisture content. The aim of this study was to formulate optimal film-forming gel compositions that would have good physico-chemical properties and be suitable for wound treatment. Nitrocellulose, castor oil, ethanol (96%), ethyl acetate, and cinnamon leaf essential oil were used to create formulations. During the study, the drying rate, adhesion, flexibility, tensile strength, cohesiveness, swelling, water vapor penetration, pH value, and morphology properties of films were examined. Results showed that optimal concentrations of nitrocellulose for film-forming gel production were 13.4% and 15%. The concentrations of nitrocellulose and cinnamon leaf essential oil impacted the films' physicochemical properties (drying rate, swelling, adhesion, flexibility, etc.). The swelling test showed that films of formulations could absorb significant amounts of simulant wound exudate. Film-forming gels and films showed no microbial contamination and were stable three months after production.

Tuning the thermodynamic, optical, and rheological properties of thermoresponsive polymer solutions via silica nanoparticle shape and concentration

HYPOTHESIS

The shape and quantity of hydrophilic silica nanoparticles (NPs) can be used to tune the microstructure, rheology, and stability of phase-separating polymer solutions. In thermoresponsive polymer systems, silica nanospheres are well-studied whereas anisotropic NPs have little literature precedent. Here, we hypothesize that NP shape and concentration lower the onset of rheological and turbidimetric transitions of aqueous poly(N-isopropyl acrylamide) (PNIPAM) solutions.

EXPERIMENTS

Differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR), turbidimetry, and oscillatory rheology are utilized to examine interactions between NPs, PNIPAM, and water and to track changes in phase separation and rheological properties due to NP concentration and shape.

FINDINGS

NP addition reduces phase separation enthalpy due to PNIPAM-NP hydrogen bonding interactions, the degree to which depends on polymer content. While NP addition minorly impacts thermodynamic and optical properties, rheological transitions and associated rheological properties are dramatically altered with increasing temperature, and depend on NP quantity, shape, and polymer molecular weight. Thus NP content and shape can be used to finely tune transition temperatures and mechanical properties for applications in stimuli-responsive materials.

Formulation and Development of Bioadhesive Oral Films Containing Usnea barbata (L.) F.H.Wigg Dry Ethanol Extract (F-UBE-HPC) with Antimicrobial and Anticancer Properties for Potential Use in Oral Cancer Complementary Therapy

Medical research explores plant extracts’ properties to obtain potential anticancer drugs. The present study aims to formulate, develop, and characterize the bioadhesive oral films containing Usnea barbata (L.) dry ethanol extract (F-UBE-HPC) and to investigate their anticancer potential for possible use in oral cancer therapy. The physicochemical and morphological properties of the bioadhesive oral films were analyzed through Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), Atomic Force Microscopy (AFM), thermogravimetric analysis (TG), and X-ray diffraction techniques. Pharmacotechnical evaluation (consisting of the measurement of the specific parameters: weight uniformity, thickness, folding endurance, tensile strength, elongation, moisture content, pH, disintegration time, swelling rate, and ex vivo mucoadhesion time) completed the bioadhesive films’ analysis. Next, oxidative stress, caspase 3/7 activity, nuclear condensation, lysosomal activity, and DNA synthesis induced by F-UBE-HPC in normal blood cell cultures and oral epithelial squamous cell carcinoma (CLS-354) cell line and its influence on both cell types’ division and proliferation was evaluated. The results reveal that each F-UBE-HPC contains 0.330 mg dry extract with a usnic acid (UA) content of 0.036 mg. The bioadhesive oral films are thin (0.093 ± 0.002 mm), reveal a neutral pH (7.10 ± 0.02), a disintegration time of 118 ± 3.16 s, an ex vivo bioadhesion time of 98 ± 3.58 min, and show a swelling ratio after 6 h of 289 ± 5.82%, being suitable for application on the oral mucosa. They displayed in vitro anticancer activity on CLS-354 tumor cells. By considerably increasing cellular oxidative stress and caspase 3/7 activity, they triggered apoptotic processes in oral cancer cells, inducing high levels of nuclear condensation and lysosomal activity, cell cycle arrest in G0/G1, and blocking DNA synthesis. All these properties lead to considering the UBE-loaded bioadhesive oral films suitable for potential application as a complementary therapy in oral cancer.

Wound dressing adherence: a review

Wound dressing adherence is an important problem that is frequently encountered in wound care, and is associated with both clinical and economic burdens. However, only a few review articles have focused on this issue. The objective of this review was to present a comprehensive discussion of wound dressing adherence, including the mechanism of dressing adherence, adverse consequences (clinical burdens and economic burdens), factors affecting adherence (dressing-, patient- and wound-related factors, and factors related to the wound care procedure), tests to assess dressing adherence (in vitro assay, in vivo assay and clinical trials), and reduction of wound adherence (modification of dressing adherence and special care in particular patients). Accordingly, this review article emphasises an awareness of dressing adherence, and is intended to be an informative source for the development of new dressings and for wound management.

Preparation and In Vitro and In Vivo Evaluation of a Testosterone Film Forming Gel for the Treatment of Hypoactive Sexual Desire Disorder in Women

Hypoactive sexual desire disorder (HSDD) is one of the most common sexual complaints in women. Currently, there is an unmet need for a drug treatment for this disorder. The purpose of this study was to develop a testosterone (TS) film forming gel used for women to treat HSDD by measuring the tackiness, peel adhesion force, tensile strength, and elasticity of the formulation. Diethylene glycol monoethyl ether (Transcutol P), an efficient penetration enhancer, was added to the optimized formulation and the transdermal permeation characteristics in vitro were studied using Franz-diffusion cells. The quantitative determination of TS was performed by high-performance liquid chromatography (HPLC). After 24 h, Transcutol P at 3% had the largest cumulative amount of drug and enhancement ratio of TS of 75.14 μg/cm² and 2.82, respectively. After the screening of film forming polymers and penetration enhancers, the optimal formulation was as follows: glycerol (1%, w/w); 12.5% sodium carboxymethylcellulose (CMC-Na) aqueous solution (0.5%, w/w); 2.5% Carbomer ethanol solution (0.5%, w/w); Transcutol P ethanol solution (3%, w/w) containing 0.5% TS; and 8% Poly vinyl alcohol (PVA) aqueous solution (30%, w/w). The optimized film forming gel had good uniformity and the release of TS in vitro was close to 100% within 24 h. In vivo studies showed the formulations had optimal area under blood drug concentration curve values in the order of 3% Transcutol P > 1% Transcutol P > 5% Transcutol P > control preparation. The formulation with 3% Transcutol P provided the highest permeation effect both in vitro and in vivo. The safety of this formulation was further evaluated with a skin irritation test. It could effectively improve the rabbit skin irritation observed with a marketed transdermal patch Androderm®. The present study provides a promising approach for the development of a novel TS film forming gel for the treatment of HSDD in women.

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.

Alginate: From Food Industry to Biomedical Applications and Management of Metabolic Disorders

Initially used extensively as an additive and ingredient in the food industry, alginate has become an important compound for a wide range of industries and applications, such as the medical, pharmaceutical and cosmetics sectors. In the food industry, alginate has been used to coat fruits and vegetables, as a microbial and viral protection product, and as a gelling, thickening, stabilizing or emulsifying agent. Its biocompatibility, biodegradability, nontoxicity and the possibility of it being used in quantum satis doses prompted scientists to explore new properties for alginate usage. Thus, the use of alginate has been expanded so as to be directed towards the pharmaceutical and biomedical industries, where studies have shown that it can be used successfully as biomaterial for wound, hydrogel, and aerogel dressings, among others. Furthermore, the ability to encapsulate natural substances has led to the possibility of using alginate as a drug coating and drug delivery agent, including the encapsulation of probiotics. This is important considering the fact that, until recently, encapsulation and coating agents used in the pharmaceutical industry were limited to the use of lactose, a potentially allergenic agent or gelatin. Obtained at a relatively low cost from marine brown algae, this hydrocolloid can also be used as a potential tool in the management of diabetes, not only as an insulin delivery agent but also due to its ability to improve insulin resistance, attenuate chronic inflammation and decrease oxidative stress. In addition, alginate has been recognized as a potential weight loss treatment, as alginate supplementation has been used as an adjunct treatment to energy restriction, to enhance satiety and improve weight loss in obese individuals. Thus, alginate holds the promise of an effective product used in the food industry as well as in the management of metabolic disorders such as diabetes and obesity. This review highlights recent research advances on the characteristics of alginate and brings to the forefront the beneficial aspects of using alginate, from the food industry to the biomedical field.

Highly Scattering Hierarchical Porous Polymer Microspheres with a High-Refractive Index Inorganic Surface for a Soft-Focus Effect

Functional light scattering materials have received considerable attention in various fields including cosmetics and optics. However, a conventional approach based on optically active inorganic materials requires considerable synthetic effort and complicated dispersion processes for special refractive materials. Here, we report a simple and effective fabrication strategy for highly scattering hierarchical porous polymer microspheres with a high-refractive index inorganic surface that mitigates the disadvantages of inorganic materials, producing organic-inorganic hybrid particles with an excellent soft-focus effect. Hierarchical organic-inorganic hybrid particles were synthesized using the simple physical mixing of porous poly (methyl methacrylate) (PMMA) microparticles with different pore sizes and regularities as the organic core and titanium dioxide (TiO₂) nanoparticles with different particle sizes as the inorganic shell. The polar noncovalent interactions between polar PMMA microspheres and the polar surface of TiO₂ nanoparticles could induce the hierarchical core-shell structure of hybrid particles. The synthesized hybrid particles had increased diffuse reflectance properties of up to 160% compared with single inorganic particles. In addition, the light scattering efficiency and soft-focus effect could be increased further, depending on the size of the TiO₂ nanoparticles and the pore characteristics of the PMMA microspheres. The proposed study can provide a facile and versatile way to improve the light scattering performance for potential cosmetics.

Application of film-forming solution as a transdermal delivery system of piperine-rich herbal mixture extract for anti-inflammation

Piperine-rich herbal mixture (PHM) used in this study is a traditional Thai medicine that contains 21 oriental herbs. It is called "Sahastara remedy" and is officially included in the Thai National List of Essential Medicine since A.D. 2011. PHM has been used orally to relieve muscle and bone pains. It contains Piper nigrum fruits as a major constituent and also Piper retrofractum fruits, PHM thus has anti-inflammatory activities that mostly come from the bioactivities of piperine consisting of these pepper fruits. Unfortunately, PHM usually causes gastrointestinal side effects. Consequently, a topical product containing an alcoholic extract of PHM (PHM-E), i.e., film-forming solution (FFS) was developed to overcome this drawback. The aims of this study were to investigate the anti-inflammatory activity of PHM-E, to evaluate physicochemical properties and the anti-inflammatory activity of FFS containing PHM-E (PHM-E FFS). Anti-inflammatory activities of PHM-E were investigated in the RAW 264.7 cells. Physicochemical properties, in vitro toxicities and anti-inflammatory activities of PHM-E FFS including its dry film (PHM-E film) were determined. PHM-E showed anti-inflammatory activities with dose dependent manners via inhibition of nitric oxide and prostaglandin E₂ production by the RAW 264.7 cells and promotion of the cell phenotype polarization from M1 to M2. PHM-E FFS had low viscosity and exhibited the Newtonian behavior. It provided elastic PHM-E film with low tensile strength. The release profile of piperine from PHM-E film followed a zero-kinetic model. PHM-E FFS demonstrated compatibility with the skin cells, minimal ocular irritant when accidentally splashing into the eye and moderate-to-high potency for inhibition of inflammatory symptoms in the rats. PHM-E FFS thus had potential for use in the further clinical study to investigate its efficacy and safety in patients.

Design and optimization of film-forming gel of etoricoxib using research surface methodology

The present investigation is focused on the development of transdermal film-forming gel (FFG) loaded with etoricoxib employing research surface methodology (RSM). Box-Behnken surface design method was used to develop experimental run using different concentrations of etoricoxib, hydroxypropyl methylcellulose (HPMC K100M), and eudragit RL100 as independent variables, and Derringer's optimization tool was employed to optimize best possible formulation. The dependent variables considered in this study were viscosity and drug permeation at 24 h (Q24, μg/cm²). Anti-inflammatory study was performed on Wistar albino rats for 8 h. Skin irritation studies and accelerated stability studies were performed for validated FFG formulations. Quadratic model was found to be best fit model (p < 0.0001) for both the responses. The influence of HPMC concentration on the viscosity was found to be highest whereas concentration of etoricoxib was maximum for Q24. The optimum composition of the FFG was observed to be 4% of etoricoxib, 1.1246% of HPMC, and 0.4% of eudragit. Above composition resulted in viscosity of 1549.5 mPa.s and maximum Q24 of 4639.11 μg/cm² with desirability 0.918. The in vivo anti-inflammatory study demonstrated better sustained release effect (for 8 h) of optimized FFG compared to orally administered drug suspension. An average irritation score of 0.555 was observed on Draize scoring system. The validated FFG formulation was found to be stable for the 3 months in accelerated conditions. It can be concluded from the above investigations that the validated FFG formulation of etoricoxib is well tolerated and could provide sustained drug release for 8 h. Graphical abstract.

Controlled Release Film Forming Systems in Drug Delivery: The Potential for Efficient Drug Delivery

Despite many available approaches for transdermal drug delivery, patient compliance and drug targeting at the desired concentration are still concerns for effective therapies. Precise and efficient film-forming systems provide great potential for controlling drug delivery through the skin with the combined advantages of films and hydrogels. The associated disadvantages of both systems (films and hydrogels) will be overcome in film-forming systems. Different strategies have been designed to control drug release through the skin, including changes to film-forming polymers, plasticizers, additives or even model drugs in formulations. In the current review, we aim to discuss the recent advances in film-forming systems to provide the principles and review the methods of these systems as applied to controlled drug release. Advances in the design of film-forming systems open a new generation of these systems.

Hybrid hydrogels for biomedical applications

The use of hydrogels in biomedical applications dates back multiple decades, and the engineering potential of these materials continues to grow with discoveries in chemistry and biology. The approaches have led to increasing complex hydrogels that incorporate both synthetic and natural polymers and functional domains for tunable release kinetics, mediated cell response, and ultimately use in clinical and research applications in biomedical practice. This review focuses on recent advances in hybrid hydrogels that incorporate nano/microstructures, their synthesis, and applications in biomedical research. Examples discussed include the implementation of click reactions, photopatterning, and 3D printing for the facile production of these hybrid hydrogels, the use of biological molecules and motifs to promote a desired cellular outcome, and the tailoring of kinetic and transport behavior through hybrid-hydrogel engineering to achieve desired biomedical outcomes. Recent progress in the field has established promising approaches for the development of biologically relevant hybrid hydrogel materials with potential applications in drug discovery, drug/gene delivery, and regenerative medicine.

Medicated Foams and Film Forming Dosage Forms as Tools to Improve the Thermodynamic Activity of Drugs to be Administered Through the Skin

Medicated foams and film forming systems are dosage forms formulated to undergo a con-trolled metamorphosis when applied on the skin. Indeed, due to the presence of propellant or a particular air-spray foam pump, a liquid can generate foam when applied on the stratum corneum, or a liquid or conventional dosage form can form on the skin a continuous film as a consequence of the solvent evapora-tion. Thanks to these controlled modifications, the drug thermodynamic activity increases favoring the skin penetration and, therefore, the bioavailability with respect to conventional semi-solid and liquid dosage forms. Furthermore, the available clinical data also evidence that these dosage forms improve the patient’s compliance. The main formulative aspects of medicated foams and film forming systems are reviewed with the aim to underline the possible advantages in terms of biopharmaceutical performances and pa-tient’s adherence.

Transdermal Evaporation Drug Delivery System: Concept to Commercial Products

Since two decades or so transdermal route established itself as better alternative to traditional oral route. This is possible due to continuous innovations in transdermal drug delivery (TDD), which not only enables researchers from academia and industry to successfully develop and launch many new pharmaceuticals but also allow to include new classes of drugs that can be developed into transdermal formulations. These successes are achieved due to the use of novel techniques based on either physical or chemical approaches. However, both of these techniques suffer due to their own disadvantages. Comparatively, a simple method of supersaturation to enhance drug permeation across skin has created a new wave of interest. Even though the application supersaturated principle in topical and TDD has been used from 1960s, but proper control of drug release and formation of stable supersaturated states has been the core of intense research in the last decade. Out of various methods used to get supersaturated system, evaporation method is considered as most efficient and practically feasible for TDD. Therefore, in this review concept of supersaturation, selection of solvent system and the mechanism of inhibition of crystallization are discussed. Application of evaporation systems in the development of transdermal formulations such as solutions, semisolids and metered dose therapeutic systems (MDTS) and the commercial evaporative systems are also discussed in this review.

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.

Development of a magnetic composite material for measurement of residual limb displacements in prosthetic sockets

INTRODUCTION

Wearable limb-socket displacement sensors may help patients and prosthetists identify a deteriorating socket fit and justify the need for repair or replacement.

METHODS

A novel sensor using an inductive sensing modality was developed to detect limb-to-socket distances. Key detection elements were a coil antenna placed in the socket wall and a magnetic composite sheath worn over the outside of the prosthesis user's elastomeric liner. The sheath was a nylon or cotton prosthetic stocking coated with a polyurethane composite. The polyurethane composite contained embedded iron particles (75 wt%).

RESULTS

Brushing γ-glycidoxypropyltriethoxysilane onto the sheath fabric, coating it first with unfilled polyurethane and then iron-filled polyurethane, enhanced bonding between the sheath and the composite and overcame mechanical degradation problems. A γ-glycidoxypropyltriethoxysilane-rich fumed silica layer applied to the outside of the sheath reduced friction and improved durability. Field testing demonstrated less than a 3% signal degradation from four weeks of field use.

CONCLUSIONS

The developed wearable displacement sensor meets durability and performance needs, and is ready for large-scale clinical testing.

Smart self-assembled microgel films as encapsulating carriers for UV-absorbing molecules

This article reports the ability of oligo(ethylene glycol)-based stimuli-responsive microgels to spontaneously form self-assembled microgel films under different conditions such as the presence or absence of water soluble polymers (WSP, formed during the microgel synthesis) and the type and/or amount of salt in the microgel dispersion.

Formulation of Polyherbal Patches Based on Polyvinyl Alcohol and Hydroxypropylmethyl Cellulose: Characterization and In Vitro Evaluation

The purpose of this research was to prepare and characterize polyherbal patches made from polyvinyl alcohol (PVA) and hydroxypropylmethyl cellulose (HPMC) with glycerine as a plasticizer. Polyherbal extracts were Luk-Pra-Kob recipes extracted with 95% ethanol. They were prepared by mixing the polymer solutions and glycerine in a beaker; subsequently, the polyherbal extracts were homogeneously mixed. Then, they were transferred into a Petri dish and dried in a hot-air oven at 70 ± 2°C for 5 h. The dry polyherbal patches were evaluated for physicochemical properties by Fourier transform infrared spectroscopy, differential scanning calorimetry, X-ray diffraction, and a scanning electron microscope. They were studied for in vitro release and skin permeation of the marker active compound (E)-4-(3',4'-dimethoxyphenyl)but-3-en-l-ol (compound D) using a modified Franz-type diffusion cell. The polyherbal patches made from PVA as a matrix layer were homogeneous, smooth, and compact relative to HPMC-containing polyherbal patches. The selected polyherbal patches made from PVA produced a release profile with an initial burst effect in which compound D release was 74.21 ± 6.13% within 8 h, but compound D could permeate the pig skin only 37.28 ± 5.52% and was highly accumulated in newborn pig skin at 35.90 ± 6.72%. The in vitro release and skin permeation kinetics of compound D were fitted to the Higuchi model. The polyherbal patches made from PVA could be suitably used for herbal medicine application.

Trans-resveratrol-loaded nonionic lamellar liquid-crystalline systems: structural, rheological, mechanical, textural, and bioadhesive characterization and evaluation of in vivo anti-inflammatory activity

Resveratrol (Res) is a common phytoalexin present in a few edible materials, such as grape skin, peanuts, and red wine. Evidence has shown the beneficial effects of Res on human health, which may be attributed to its anti-inflammatory activity. However, the poor aqueous solubility of Res limits its therapeutic effectiveness. Therefore, the use of nanostructured delivery systems for Res, such as liquid-crystalline systems, could be beneficial. In this study, we aimed to develop, characterize, and determine the in vivo effectiveness of Res-loaded liquid-crystalline systems. Systems containing copaiba balsam oil, polyethylene glycol-40 hydrogenated castor oil, and water were designed. Results of polarized light microscopy, small-angle X-ray scattering, texture-profile analysis, and flow-rheology analysis showed that the Res-loaded liquid-crystalline system had a lamellar structure, textural and mechanical (hardness, compressibility, and adhesiveness) properties, and behaved as a non-Newtonian fluid, showing pseudoplastic behavior upon skin application. Furthermore, all liquid-crystalline systems presented bioadhesive properties that may have assisted in maintaining the anti-inflammatory activity of Res, since the topical application of the Res-loaded lamellar mesophase liquid crystals resulted in edema inhibition in a carrageenan-induced paw-inflammation mouse model. Therefore, Res-loaded lamellar mesophases represent a promising new therapeutic approach for inhibition of skin inflammation.

Vegetable oil hybrid films cross-linked at the air-water interface: formation kinetics and physical characterization

Vegetable oil based hybrid films were developed thanks to a novel solvent- and heating-free method at the air-water interface using silylated castor oil cross-linked via a sol-gel reaction. To understand the mechanism of the hybrid film formation, the reaction kinetics was studied in detail by using complementary techniques: rheology, thermogravimetric analysis, and infrared spectroscopy. The mechanical properties of the final films were investigated using nano-indentation, whereas their structure was studied using a combination of wide-angle X-ray scattering, electron diffraction, and atomic force microscopy. We found that solid and transparent films form in 24 hours and, by changing the silica precursor to castor oil ratio, their mechanical properties are tunable in the MPa-range by about a factor of twenty. In addition to that, a possible optimization of the cross-linking reaction with different catalysts was explored, and finally cytotoxicity tests were performed on fibroblasts proving the absence of film toxicity. The results of this work pave the way to a straightforward synthesis of castor-oil films with tunable mechanical properties: hybrid films cross-linked at the air-water interface combine an easy and cheap spreading protocol with the features of their thermal history optimized for possible future micro/nano drug loading, thus representing excellent candidates for the replacement of non-environmentally friendly petroleum-based materials.

Film forming systems for topical and transdermal drug delivery

Skin is considered as an important route of administration of drugs for both local and systemic effects. The effectiveness of topical therapy depends on the physicochemical properties of the drug and adherence of the patient to the treatment regimen as well as the system's ability to adhere to skin during the therapy so as to promote drug penetration through the skin barrier. Conventional formulations for topical and dermatological administration of drugs have certain limitations like poor adherence to skin, poor permeability and compromised patient compliance. For the treatment of diseases of body tissues and wounds, the drug has to be maintained at the site of treatment for an effective period of time. Topical film forming systems are such developing drug delivery systems meant for topical application to the skin, which adhere to the body, forming a thin transparent film and provide delivery of the active ingredients to the body tissue. These are intended for skin application as emollient or protective and for local action or transdermal penetration of medicament for systemic action. The transparency is an appreciable feature of this polymeric system which greatly influences the patient acceptance. In the current discussion, the film forming systems are described as a promising choice for topical and transdermal drug delivery. Further the various types of film forming systems (sprays/solutions, gels and emulsions) along with their evaluation parameters have also been reviewed.

Acmella oleracea and Achyrocline satureioides as Sources of Natural Products in Topical Wound Care

The Brazilian forests have one of the world's biggest biodiversities. Achyrocline satureioides (macela) and Acmella oleracea (jambu) are native species from Brazil with a huge therapeutic potential, with proved anti-inflammatory and anesthetic action, respectively. The jambu's crude extract after depigmentation with activated charcoal and macela's essential oil were incorporated in a film made with hydroxyethyl cellulose. Those films were evaluated by mechanical test using a texturometer and anti-inflammatory and anesthetic activities by in vivo tests: wound healing and antinociceptive. The film containing the highest concentration of depigmented jambu's extract and macela's essential oil obtained an anesthesia time of 83.6 (±28.5) min longer when compared with the positive control EMLA®; the same occurred with the wound healing test; the film containing the highest concentration had a higher wound contraction (62.0% ± 12.1) compared to the positive control allantoin and the histopathological analysis demonstrated that it increases collagen synthesis and epidermal thickening. The results demonstrate that the films have a potential use in skin wounds, pressure sore, and infected surgical wounds treatment.

Composites of Polymer Hydrogels and Nanoparticulate Systems for Biomedical and Pharmaceutical Applications

Due to their unique structures and properties, three-dimensional hydrogels and nanostructured particles have been widely studied and shown a very high potential for medical, therapeutic and diagnostic applications. However, hydrogels and nanoparticulate systems have respective disadvantages that limit their widespread applications. Recently, the incorporation of nanostructured fillers into hydrogels has been developed as an innovative means for the creation of novel materials with diverse functionality in order to meet new challenges. In this review, the fundamentals of hydrogels and nanoparticles (NPs) were briefly discussed, and then we comprehensively summarized recent advances in the design, synthesis, functionalization and application of nanocomposite hydrogels with enhanced mechanical, biological and physicochemical properties. Moreover, the current challenges and future opportunities for the use of these promising materials in the biomedical sector, especially the nanocomposite hydrogels produced from hydrogels and polymeric NPs, are discussed.

Formulation, physicochemical characterization, and in vitro study of chitosan/HPMC blends-based herbal blended patches

The current work prepared chitosan/hydroxypropyl methylcellulose (HPMC) blends and studied the possibility of chitosan/HPMC blended patches for Zingiber cassumunar Roxb. The blended patches without/with crude Z. cassumunar oil were prepared by homogeneously mixing the 3.5% w/v of chitosan solution and 20% w/v of HPMC solution, and glycerine was used as plasticizer. Then, they were poured into Petri dish and produced the blended patches in hot air oven at 70 ± 2°C. The blended patches were tested and evaluated by the physicochemical properties: moisture uptake, swelling ratio, erosion, porosity, Fourier transform infrared spectroscopy, differential scanning calorimetry, and X-ray diffraction, and photographed the surface and cross-section morphology under SEM technique. Herbal blended patches were studied by the in vitro release and skin permeation of active compound D. The blended patches could absorb the moisture and became hydrated patches that occurred during the swelling of blended patches. They were eroded and increased by the number of porous channels to pass through out for active compound D. In addition, the blended patches indicated the compatibility of the blended ingredients and homogeneous smooth and compact. The blended patches made from chitosan/HPMC blends provide a controlled release and skin permeation behavior of compound D. Thus, the blended patches could be suitably used for herbal medicine application.

Wound healing efficacy of a chitosan-based film-forming gel containing tyrothricin in various rat wound models

The objective of this study was to evaluate the healing effects of a chitosan-based, film-forming gel containing tyrothricin (TYR) in various rat wound models, including burn, abrasion, incision, and excision models. After solidification, the chitosan film layer successfully covered and protected a variety of wounds. Wound size was measured at predetermined timepoints after wound induction, and the effects of the film-forming gel were compared with negative (no treatment) and positive control groups (commercially available sodium fusidate ointment and TYR gel). In burn, abrasion and excision wound models, the film-forming gel enabled significantly better healing from 1 to 6 days after wound induction, compared with the negative control. Importantly, the film-forming gel also enabled significantly better healing compared with the positive control treatments. In the incision wound model, the breaking strength of wound strips from the group treated with the film-forming gel was significantly increased compared with both the negative and positive control groups. Histological studies revealed advanced granulation tissue formation and epithelialization in wounds treated with the film-forming gel. We hypothesize that the superior healing effects of the film-forming gel are due to wound occlusion, conferred by the chitosan film. Our data suggest that this film-forming gel may be useful in treating various wounds, including burn, abrasion, incision and excision wounds.

Use of lipolanthionine peptide, a toll-like receptor 2 inhibitor, enhances transdermal delivery efficiency

The transdermal delivery system (TDS) is able to obtain a systemic therapeutic effect by administration through the skin, which has low side effects and is able to maintain a sustained blood concentration. However, due to the barrier presented by the stratum corneum, numerous drugs have poor percutaneous permeability. Therefore, the improvement of skin permeability is key to TDS. The main method of promoting transdermal absorption is through the usage of penetration enhancers. Dimethyl sulfoxide (DMSO) is a commonly used penetration enhancer, which has anti-inflammatory analgesic effects and is able to penetrate the skin. Retinoic acid (RA) and lipolanthionine peptide (LP) may also benefit the permeation efficiency of TDS. Therefore, the present study examined the function of DMSO, RA and LP as penetration enhancers in TDS. Firstly, the optimum concentration of DMSO was confirmed by detecting the expression of the LacZ gene in vitro. Secondly, different combinations of LP, RA and DMSO were applied to mouse skin to analyze the penetration enhancer combination with the greatest efficacy. All the animals were divided into five groups: The RA + LP + DMSO + pORF-LacZ group, the RA + DMSO + pORF-LacZ group, the LP + DMSO + pORF-LacZ group, the DMSO + pORF-LacZ group and the control group. Skin was soaked in combinations of LP, RA and DMSO for seven days and then the pORF-LacZ plasmids were daubed onto the skin once daily three days. On the 11th day, all the animals were sacrificed by cervical dislocation and the skin and blood samples were collected. The blood samples were used to detect the expression of the LacZ gene by quantitative polymerase chain reaction and the skin samples were used to detect the expression of claudin-4 and zonula occluden-1 (ZO-1) proteins by immunohistochemistry and western blot analysis. The results demonstrated that the combination of LP, RA and DMSO exhibited the greatest transdermal delivery efficiency, which verified that RA and LP were able to increase the penetration effects. Following treatment with LP, the symptoms of dermal edema were relieved and the capillaries contracted, which suggested that LP was a safe and effective penetration enhancer able to reduce the side-effects caused by DMSO. The present study provides a guideline for the synthesis of novel penetration enhancers.

Design, formulation and optimization of valsartan transdermal gel containing iso-eucalyptol as novel permeation enhancer: preclinical assessment of pharmacokinetics in Wistar albino rats

OBJECTIVE

The aim of this study was to develop and optimize a transdermal gel formulation of valsartan using Box-Behnken design and to evaluate it for pharmacokinetic study.

METHODS

The independent variables were Carbopol 940 (X1), PEG 400 (X2) and ethanol (X3) while valsartan flux (Y1), Tlag (Y2) and gel viscosity (Y3) were the dependent variables. Iso-eucalyptol was added in all gel formulations as permeation enhancer except for control gel.

RESULTS

It was observed that the permeation rate of valsartan significantly increased in direct proportion to the ethanol concentration, but significantly decreased in direct proportion to polymer concentration. Lag time and viscosity decreased in reverse proportion to ethanol concentration. The optimized valsartan gel formulation (VGF-OPT) yielded flux of 143.27 ± 7.11 µg/cm(2)/h and 27.55 ± 2.51 µg/cm(2)/h across rat and human cadaver skin, respectively. In vivo pharmacokinetic study of VGF-OPT-transdermal therapeutic system containing iso-eucalyptol showed a significant increase in the bioavailability (2.52 times) compared with oral formulation of valsartan by virtue of better permeation through Wistar rat skin.

CONCLUSION

It was concluded that the developed transdermal gel accentuates the flux of valsartan and could be used as an antihypertensive dosage form for effective transdermal delivery of valsartan.

Physicochemical properties and anti-Propionibacterium acnes activity of film-forming solutions containing alpha-mangostin-rich extract

The objective of this study was to study the effect of formulation compositions on physicochemical properties and anti-Propionibacterium acnes activity of film-forming solutions containing alpha-mangostin-rich extract (AM). Film-forming solution bases and film-forming solutions containing AM were prepared by using Eudragit RL PO or Klucel LF or combinations of them as film-forming polymers. Rheological properties, pH values of the solutions, and mechanical properties of the dry films were investigated. An optimized formulation was selected and evaluated for the film surface, in vitro AM release, an anti-P. acnes activity, and potential for being a skin irritant. It was found that mechanical properties of the dry films were affected by total polymer contents, ratios of Klucel LF/Eudragit RL PO, AM, and contents of triethyl citrate. The film-forming solutions containing AM had pH values around 7.0. Their flow curves exhibited Newtonian flow behaviors. The optimized formulation provided films possessing smooth and nonporous surfaces. These films showed greater anti-P. acnes activity than their base films without toxicity to skin fibroblasts. Furthermore, AM released from the film matrix obeyed Higuchi's equation. In conclusion, the film-forming solutions containing AM had potential for treatment of acne vulgaris caused by P. acnes. However, further in vivo study is necessary to determine their efficacy and safety for using in patients suffering from acne vulgaris.

Fumarate copolymers-based membranes overlooking future transdermal delivery devices: synthesis and properties

Novel copolymers of vinyl acetate and dialkylfumarates, poly(VA-co-DRF) with R = isopropyl (DIPF) or octan-2-yl (DOF), were synthesized by radical copolymerization under microwave conditions. The products were characterized by (1)H NMR and FTIR spectroscopies, size exclusion chromatography and differential scanning calorimetry. Based on these copolymers three membranes supported on polyvinyl alcohol were prepared and their morphology, swelling and mechanical properties were studied. The swelling kinetic was analyzed and interpreted in light of the Fick transport model, showing that the water transport occurs through a non-Fickian diffusion mechanism. The results show that the membrane prepared of poly(VA-co-DOF) exhibited excellent properties as potential platform for transdermal delivery system: they exhibited good tensile strength, moderated swelling and form thin and transparent films.

Design and in vitro evaluation of transdermal patches based on ibuprofen-loaded electrospun fiber mats

To improve the poor compatibility among different components of Drug-in-adhesive type patch, two novel plasters (Drug-in-fiber and Drug-in-adhesive/fiber) were developed based on ibuprofen (IBU)-loaded fiber mats. These fibrous mats were fabricated via electrospinning of cellulose acetate/poly(vinylpyrrolidone) composites in a binary solvent of N,N-dimethyl acetamide/acetone. Physical status studies suggested that Drug-in-fiber could inhibit IBU re-crystallization, but the active ingredients were released at a relatively slow rate due to the dual-resistance of fiber mat and adhesive matrix. To overcome this shortcoming, Drug-in-adhesive/fiber was designed by coupling medicated hydrophilic pressure sensitive adhesive and IBU-loaded fiber mat. This method endowed Drug-in-adhesive/fiber a fast IBU release rate and high permeated drug amount though simulative skins. This design separated enhancer from adhesive matrix, which guaranteed Drug-in-adhesive/fiber excellent adhesion forces. Hence, the plasters based on medicated fiber mats improved the compatibility among patch components.

Dual drug-loaded nanoparticles on self-integrated scaffold for controlled delivery

Antioxidant (quercetin) and hypoglycemic (voglibose) drug-loaded poly-D,L-lactideco-glycolide nanoparticles were successfully synthesized using the solvent evaporation method. The dual drug-loaded nanoparticles were incorporated into a scaffold film using a solvent casting method, creating a controlled transdermal drug-delivery system. Key features of the film formulation were achieved utilizing several ratios of excipients, including polyvinyl alcohol, polyethylene glycol, hyaluronic acid, xylitol, and alginate. The scaffold film showed superior encapsulation capability and swelling properties, with various potential applications, eg, the treatment of diabetes-associated complications. Structural and light scattering characterization confirmed a spherical shape and a mean particle size distribution of 41.3 nm for nanoparticles in the scaffold film. Spectroscopy revealed a stable polymer structure before and after encapsulation. The thermoresponsive swelling properties of the film were evaluated according to temperature and pH. Scaffold films incorporating dual drug-loaded nanoparticles showed remarkably high thermoresponsivity, cell compatibility, and ex vivo drug-release behavior. In addition, the hybrid film formulation showed enhanced cell adhesion and proliferation. These dual drug-loaded nanoparticles incorporated into a scaffold film may be promising for development into a transdermal drug-delivery system.