Development of topical hydrogels of terbinafine hydrochloride and evaluation of their antifungal activity

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.

Evaluation of the Efficacy of Amphotericin B and Terbinafine Microemulsions and Their Combination on Cutaneous Leishmaniasis and Comparison with the Conventional Drug Form in BALB/c Mice

Intracellular parasitic protozoa of Leishmania sp. causes leishmaniasis. The restricted access of the drugs to affected cells in the treatment of intracellular infections such as leishmaniasis is frequently hampered. Furthermore, most of today's drugs have limited uses due to some containing toxic compounds, and drug resistance is on the rise. In the present investigation, Amphotericin B (AmB) and Terbinafine (Tbf) were loaded in microemulsion (ME) in combination and alone, and the in vivo efficacy was considered in BALB/c mice infected with Leishmania major (L. major). The wound size at the base of the mouse tail was measured, and real-time PCR was performed to quantify the parasite load after the infection challenge. The study demonstrated that the ME-AmB and ME-Tbf formulations are safe and effective compounds for the treatment of cutaneous leishmaniasis by enhancing the effectiveness of AmB and Tbf in reducing the parasite burden.

Novel Hydrogels for Topical Applications: An Updated Comprehensive Review Based on Source

Active pharmaceutical ingredients (API) or drugs are normally not delivered as pure chemical substances (for the prevention or the treatment of any diseases). APIs are still generally administered in prepared formulations, also known as dosage forms. Topical administration is widely used to deliver therapeutic agents locally because it is convenient and cost-effective. Since earlier civilizations, several types of topical semi-solid dosage forms have been commonly used in healthcare society to treat various skin diseases. A topical drug delivery system is designed primarily to treat local diseases by applying therapeutic agents to surface level parts of the body such as the skin, eyes, nose, and vaginal cavity. Nowadays, novel semi-solids can be used safely in pediatrics, geriatrics, and pregnant women without the possibility of causing any allergy reactions. The novel hydrogels are being used in a wide range of applications. At first, numerous hydrogel research studies were carried out by simply adding various APIs in pure form or dissolved in various solvents to the prepared hydrogel base. However, numerous research articles on novel hydrogels have been published in the last five to ten years. It is expected that novel hydrogels will be capable of controlling the APIs release pattern. Novel hydrogels are made up of novel formulations such as nanoparticles, nanoemulsions, microemulsions, liposomes, self-nano emulsifying drug delivery systems, cubosomes, and so on. This review focus on some novel formulations incorporated in the hydrogel prepared with natural and synthetic polymers.

A Review on Antifungal Efficiency of Plant Extracts Entrenched Polysaccharide-Based Nanohydrogels

Human skin acts as a physical barrier; however, sometimes the skin gets infected by fungi, which becomes more severe if the infection occurs on the third layer of the skin. Azole derivative-based antifungal creams, liquids, or sprays are available to treat fungal infections; however, these formulations show various side effects on the application site. Over the past few years, herbal extracts and various essential oils have shown effective antifungal activity. Additionally, autoxidation and epimerization are significant problems with the direct use of herbal extracts. Hence, to overcome these obstacles, polysaccharide-based nanohydrogels embedded with natural plant extracts and oils have become the primary choice of pharmaceutical scientists. These gels protect plant-based bioactive compounds and are effective delivery agents because they release multiple bioactive compounds in the targeted area. Nanohydrogels can be applied to infected areas, and due to their contagious nature and penetration power, they get directly absorbed through the skin, quickly reaching the skin's third layer and effectively reducing the fungal infection. In this review, we explain various skin fungal infections, possible treatments, and the effective utilization of plant extract and oil-embedded polysaccharide-based nanohydrogels.

PLGA based film forming systems for superficial fungal infections treatment

As proven in clinical trials, superficial fungal infections can be effectively treated by single topical application of terbinafine hydrochloride (Ter-HCl) in a film forming system (FFS). Poly(lactic-co-glycolic acid) (PLGA) derivatives, originally synthesized with intention to get carriers with optimized properties for drug delivery, and multifunctional plasticizers - ethyl pyruvate, methyl salicylate, or triacetin - were used for formulation of Ter-HCl loaded FFSs. After spraying, a biodegradable, transparent, adhesive, and occlusive thin layer is formed on the skin, representing drug depot. In situ formed films were characterized by thermal, structural, viscoelastic, and antifungal properties as well as drug release and skin penetration. DSC and SEM showed fully amorphous films with Ter-HCl dissolved in PLGA in high concentration (up to 15%). FFSs are viscoelastic fluids with viscosity which can be easily adjusted by the type of plasticizer used and its concentration. The formulations showed excellent bioadhesion properties, thus ensuring persistence on the skin. In situ film based on branched PLGA/A plasticized with 10% of ethyl pyruvate allowed prolonged release of Ter-HCl by linear kinetics for the first 6 days with a total time of almost 14 days. During ex vivo human skin penetration experiment, Ter-HCl was found to be located only in its target layer, the epidermis. According to our results, plasticized branched PLGA derivatives loaded by Ter-HCl are suitable for the development of FFSs for superficial fungal infections treatment.

Development and Evaluation of Polymeric Nanosponge Hydrogel for Terbinafine Hydrochloride: Statistical Optimization, In Vitro and In Vivo Studies

Terbinafine hydrochloride, although one of the prominent antifungal agents, suffers from low drug permeation owing to its hydrophobic nature. The approach of nanosponge formulation may thus help to resolve this concern. Thus, the present research was envisioned to fabricate the nanosponge hydrogel of terbinafine hydrochloride for topical delivery since nanosponge augments the skin retentivity of the drug. The optimized formulation was obtained using Box Behnken Design. The dependent and independent process parameters were also determined wherein polyvinyl alcohol (%), ethylcellulose (%), and tween 80 (%) were taken as independent process parameters and particle size, polydispersity index (PDI), and entrapment efficiency (EE) were the dependent parameters. The nanosponge was then incorporated into the hydrogel and characterized. In-vitro drug release from the hydrogel was 90.20 ± 0.1% which was higher than the drug suspension and marketed formulation. In vitro permeation potential of the developed formulation through rat skin showed a flux of 0.594 ± 0.22 µg/cm²/h while the permeability coefficient was 0.059 ± 0.022 cm/s. Nanosponge hydrogel was evaluated for non-irritancy and antifungal activity against C. albicans and T. rubrum confirming the substantial outcome. Tape stripping studies exhibited ten times stripping off the skin quantified 85.6 ± 0.21 μg/cm². The confocal analysis justified the permeation potential of the prepared hydrogel. The mean erythemal score was 0.0, confirming that the prepared hydrogel did not cause erythema or oedema. Therefore, based on results obtained, nanosponge hydrogel formulation is a potential carrier for efficient topical delivery of terbinafine hydrochloride.

Thermoreversible mucoadhesive polymer-drug dispersion for sustained local delivery of budesonide to treat inflammatory disorders of the GI tract

Mucoadhesive drug formulations have been studied and used as alternatives to conventional formulations in order to achieve prolonged retention at the intended site. In addition to providing a controlled drug release, several drugs and disease conditions might benefit from mucoadhesive formulations, contributing to better therapeutic outcomes. Here, we describe the development and the in vitro/in vivo characterization of a mucoadhesive in situ gellifying formulation using PF127, a thermo reversible polymer, entrapping budesonide (BUD), a potent corticosteroid used for the treatment of a wide range of inflammatory diseases, including those affecting mucosas, such as in the GI tract. PF127 formulations (15-17%) were successfully prepared by a cold method as a thermo reversible in situ gelling dispersion for mucosal drug delivery, as confirmed by DSC. Sol-gel temperatures of PF127 formulations (25-39 °C) were observed by dynamic gelation and determined by microrheology and oscillatory rheometry. X-ray diffractograms and TEM images showed that BUD was completely solubilized within the polymeric micelles. In vitro, the gels showed 5-14 g force of mucoadhesion, and the ex vivo studies confirmed that the formulation efficiently adhered to the mucosa. Histopathological analysis combined with fluorescence images and ex vivo intestinal permeation confirmed that the formulation remained on the TGI mucosa for at least 4 h after administration. In vivo studies conducted in a murine model of intestinal mucositis demonstrated that the 16% PF127 BUD formulation was able to resolve the inflammatory injury in the intestinal mucosa. Results demonstrate that fine-tuning of PF127 formulations along with adequate selection of the drug agent, thorough characterization of the dispersions and their interactions with biological interfaces leads to the development of effective controlled drug delivery systems targeted to GI inflammatory diseases.

Novel Drug Delivery Strategies for the Treatment of Onychomycosis

Onychomycosis accounts for 50% of all nail disease cases and is commonly caused by dermatophytes. It was primarily considered a cosmetic problem but has been garnering attention lately due to its persistent nature and difficult treatment with relapses. With prolonged treatment duration and high cost involved in treating onychomycosis, several attempts have been made in overcoming the rigid nail barrier. The conventional treatment of onychomycosis involves oral and topical therapy. The oral antifungal agents though quite effective, are hepato-toxic and cause drug-drug interactions. Topical therapy is more patient compliant being devoid of such adverse effects but it suffers from another setback of improper nail penetration. Amorolfine and ciclopirox nail lacquers are popular market products. Since decades, efforts have been made to enhance topical delivery for efficiently treating onychomycosis. Mechanical, physical and chemical methods have been employed. Despite all the attempts made, the nail delivery issues are far from being solved. Recently, the focus has shifted to novel drug delivery systems like nanoparticles, microemulsions, polymeric films and nail lacquers for enhanced drug permeation and localized therapy. The research around the world is exploring their potential as effective treatment options. This review intends to further explore the novel delivery strategies to treat a persistent fungal infection like onychomycosis.

Evaluation of micelles incorporated into thermosensitive hydrogels for intratumoral delivery and controlled release of docetaxel: A dual approach for in situ treatment of tumors

The in situ gelling hybrid hydrogel system has been reported to effectively concentrate chemotherapeutic drugs at the tumor site and sustain their release for a long period. DTX-micelles (docetaxel-loaded mixed micelles) are able to increase the solubility of DTX in water, and then a high drug loading rate of hydrogels can be achieved by encapsulating the docetaxel-loaded mixed micelles into the hydrogels. The thermosensitive nature of DTX-MM-hydrogels (thermosensitive hydrogels incorporated with docetaxel-loaded mixed micelles) can accelerate the formation of a depot of this drug-loaded system at the site of administration. Therefore, the hydrogels provide a much slower release compared with DTX-micelles and DTX-injection. An in vivo retention study has demonstrated that the DTX-MM-hydrogels can prolong the drug retention time and in vivo trials have shown that the DTX-MM-hydrogels have a higher antitumor efficacy and systemic safety. In conclusion, the DTX-MM-hydrogels prepared in this study have considerable potential as a drug delivery system, with higher tumor inhibition effects and are less toxic to normal tissues.

Study on montmorillonite–chlorhexidine acetate–terbinafine hydrochloride intercalation composites as drug release systems

This paper focuses on the intercalation of chlorhexidine acetate (CA) and terbinafine hydrochloride (TBH) into montmorillonite as sustained release drug carriers. The intercalation compounds were characterized by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and thermogravimetric analysis (TGA). The basal spacing of montmorillonite increased from 1.23 to 2.97 nm. It was confirmed that CA and TBH molecules were well-stabilized in the interlayer space of clay via mono-, double or triplicate layer stacking. The adsorption amounts and molecular structures of CA and TBH appeared to depend on the cation exchange capacity of MMT, which in turn, tailored the drug release patterns. In vitro release tests of MMT–CA–TBH in 0.9 wt% NaCl solution at 37 °C show a biphasic and sustained profile of CA and TBH ion release. After release, dissolution–diffusion kinetic models were fitted. The mechanism of MMT–CA–TBH release is probably due to surface diffusion and bulk diffusion via ionic exchange of MMT ions on or in the MMT with ions in the NaCl solution. The in vitro release experiments revealed that CA and TBH were released from MMT steadily, depending on the cooperation between the drugs themselves and the electrostatic interactions between the drugs and MMT. It was found that the cross-linking ratio increased due to a decrease in the free volume available for diffusion.

This paper focuses on the intercalation of chlorhexidine acetate (CA) and terbinafine hydrochloride (TBH) into montmorillonite as sustained release drug carriers.

In vitro assessment of non-irritant microemulsified voriconazole hydrogel system

Research was aimed on microemulsion-based hydrogel for voriconazole. Oleic acid and isopropyl myristate as lipid phases; tween 20: tween 80 as surfactants and PEG600 as cosurfactant were selected to formulate voriconazole microemulsions. The promising microemulsions in terms of zeta potential, pH, viscosity, and drug release were selected and developed into hydrogels using carbopol 934. Resulting microemulsion-based hydrogel (MBH) of voriconazole were evaluated for in vitro diffusion and ex vivo permeation. Antifungal potentials of MBH were assessed against selected fungal strains. Optimal MBH formulations, O6 and O8 had displayed their antifungal potentials with enlarged zone of inhibition against selected fungal strains.

In vitro microbicidal, anti-biofilm and cytotoxic effects of different commercial antiseptics

Topical antiseptics are widely used for wound treatment, with the goal of disrupting biofilm capacity. We analysed the effectiveness of a variety of antiseptics to inhibit various stages of biofilm formation and to remove biofilms in vitro as well as the agents' cytotoxic effects on fibroblasts. We found that the chlorine-releasing agents exhibited immediate anti-biofilm effects in the short term, with lesser cytotoxicity than agents prepared from more stable compounds, such as biguanide or modified diallyl disulfide-oxide, which, conversely, have better long-term effectiveness. Among the examined organisms, Gram-positive bacteria and Candida albicans were the most sensitive to the antiseptics, whereas Pseudomonas aeruginosa and Acinetobacter baumannii were relatively resistant to them. Formulations whose mechanisms of action involve the release of chemically active chlorine were more effective when administered in solution than the gel form, likely because of the stability of the active ingredients during or after preparation of the formula. Interestingly, hypochlorous acid and some superoxidation solutions were effective in preventing biofilm formation within a short time period and showed virtually no toxicity. Our study indicates that most antiseptics remain effective long enough to prevent biofilm formation; thus, even brief application of an antiseptic agent during initial wound treatment can lead to better wound management outcomes.

Enhanced topical delivery of tacrolimus by a carbomer hydrogel formulation with transcutol P

Tacrolimus (TAC), a non-steroidal anti-inflammatory and immunosuppressive agent, is used for the treatment of atopic dermatitis (AD) and skin immune diseases. TAC-loaded topical hydrogel formulations composed of carbomer, carnosine, transcutol P (diethylene glycol monoethyl ether) and humectant were prepared. For comparison, TAC-loaded topical cream-type formulations were also prepared and commercially available TAC ointment was used as a reference. A drug release study in vitro revealed that the total amount of TAC released from hydrogels over 24 h was approximately 30 times greater than that for the reference formulation. Compared to the reference ointment and creams, carbomer gel formulations showed higher skin permeation and retention of TAC (significantly different at p < 0.05), especially those with more than 10% of transcutol P. Therefore, carbomer gel formulations with sufficient levels of transcutol P are good candidates for skin delivery of TAC and have potential as therapeutic agents for the treatment of AD or immune skin disorders.

DA 5505: a novel topical formulation of terbinafine that enhances skin penetration and retention

Topical fungal infections can become severe if left untreated. Efficient treatment modalities for topical fungal infections aid the penetration of antifungal agents deep into viable skin layers. Terbinafine is a fungicidal agent that inhibits ergosterol, an essential fungal component. The main objective of this study was to evaluate skin permeation and retention of a terbinafine-loaded solution containing chitosan as a film former. Comparative assessment of skin permeation and retention was performed using a prepared formulation (DA 5505) and marketed formulations of terbinafine in murine and porcine skin. To mimic fungal infection of skin, keratinized skin was induced in NC/Nga mice. In comparison with the marketed formulations, DA 5505 exhibited significantly better skin permeation. The flux, permeation coefficient, and enhancement ratio of terbinafine were remarkably increased by DA 5505 in comparison with the marketed formulations, and lag time was dramatically reduced. DA 5505 significantly increased cumulative terbinafine retention in viable skin layers in comparison with the marketed solution, suggesting enhanced efficacy. Furthermore, DA 5505 exhibited superior skin permeation in normal skin and keratinized skin. Thus, the DA 5505 formulation has the potential to effectively deliver terbinafine to superficial and deep cutaneous fungal infections.

Stability of chitosan-a challenge for pharmaceutical and biomedical applications

Chitosan-one of the natural multifunctional polymers-due to its unique and versatile biological properties is regarded as a useful compound in medical and pharmaceutical technology. Recently, considerable research effort has been made in order to develop safe and efficient chitosan products. However, the problem of poor stability of chitosan-based systems restricts its practical applicability; thus, it has become a great challenge to establish sufficient shelf-life for chitosan formulations. Improved stability can be assessed by controlling the environmental factors, manipulating processing conditions (e.g., temperature), introducing a proper stabilizing compound, developing chitosan blends with another polymer, or modifying the chitosan structure using chemical or ionic agents. This review covers the influence of internal, environmental, and processing factors on the long-term stability of chitosan products. The aim of this paper is also to highlight the latest developments which enable the physicochemical properties of chitosan-based applications to be preserved upon storage.