Human-relevant concentrations of the antifungal drug clotrimazole disrupt maternal and fetal steroid hormone profiles in rats.

Clotrimazole is a non-prescription and broad-spectrum antifungal drug sold under brand names such as Canesten® and Lotrimin®. It is used to treat different types of fungal infections, from oral thrush to athlete's foot and vaginal mycosis. The level of exposure to clotrimazole is uncertain, as the exact usage amongst self-medicating patients is unclear. Recent studies have raised potential concern about the unsupervised use of clotrimazole during pregnancy, especially since it is a potent inhibitor of CYP enzymes of the steroidogenesis pathway. To address some of these concerns, we have assessed the effects of intrauterine exposure to clotrimazole on developing rat fetuses. By exposing pregnant rats to clotrimazole 25 or 75 mg/kg bw/day during gestation days 7-21, we obtained internal fetal concentrations close to those observed in humans. These in vivo data are in strong agreement with our physiologically-based pharmacokinetic (PBK)-modelled levels. At these doses, we observed no obvious morphological changes to the reproductive system, nor shorter male anogenital distance; a well-established morphometric marker for anti-androgenic effects in male offspring. However, steroid hormone profiles were significantly affected in both maternal and fetal plasma, in particular pronounced suppression of estrogens was seen. In fetal testes, marked up-concentration of hydroxyprogesterone was observed, which indicates a specific action on steroidogenesis. Since systemic clotrimazole is rapidly metabolized in humans, relevant exposure levels may not in itself cause adverse changes to the reproductive systems. Its capacity to significantly alter steroid hormone concentrations, however, suggests that clotrimazole should be used with caution during pregnancy.

Clotrimazole multiple W/O/W emulsion as anticandidal agent: Characterization and evaluation on skin and mucosae.

Clotrimazole (CLT) was formulated in a multiple W/O/W emulsion (ME) with the aim of evaluating its potential as topical anticandidal agent and comparing with marketed products. A previously evaluated CLT-ME was selected and physicochemically characterized. The in vitro release behavior and the ex vivo permeation profiles were assessed using Franz diffusion cells using three different types of biological membranes: human skin and porcine buccal, sublingual and vaginal mucosae. The antifungal activity against Candida strains was also tested. Results showed CLT-MEs sizes of 29.206 and 47.678 µm with skin compatible pH values of 6.47 and 6.42 exhibiting high zeta potential values of -55.13 and -55.59 mV with dependence on the pH variation. The physicochemical stability was kept for a period of 180 days of storage at room temperature. CLT-MEs exhibited pseudoplastic behavior with hysteresis areas and viscosities of 286 and 331 mPa⋅s showing higher spreadability properties than commercial counterparts. An improved CLT release pattern was supplied by the ME system following a hyperbolic model. Likewise, ME system gave higher skin permeation flux of CLT than commercial reference. CLT amounts retained in the skin and mucosae were also higher than commercial references, which coupled with the higher antimycotic efficacy make CLT-MEs a great tool for clinical investigation of topical candidiasis treatments.

Biopharmaceutical profile of a clotrimazole nanoemulsion: Evaluation on skin and mucosae as anticandidal agent.

Clotrimazole (CLT) was formulated in a nanoemulsion (NE) for the topical treatment of candidiasis consisting of 10% labrafac® lipophile, 60% labrasol®:capryol® 90 mixture (ratio 4:1) and 30% propylene glycol. Physicochemical properties, stability, rheology, in vitro drug release, ex vivo drug permeation through human skin and porcine buccal, sublingual and vaginal mucosae, antifungal efficacy, as well as in vivo skin tolerance were evaluated. 1% CLT-NE (CLT-NE1) and 2% CLT-NE (CLT-NE2) exhibited 153 ±â€¯17.25 and 186 ±â€¯15.38 nm droplet sizes, low polydispersity indexes, negative zeta potentials and biocompatible pH values. The CLT-NEs exhibited typical Newtonian profiles with viscosities of 42.14 ±â€¯0.037 mPa·s and 41.35 ±â€¯0.041 mPa·s, respectively and higher extensibility properties than commercial counterparts retaining their physicochemical properties for 180 days. NEs provided a sustained release of drug according to the first order model. Similar skin permeation properties were observed between CLT-NE1 and commercial reference. However, significant higher CLT amounts retained in mucosae were provided by CLT-NE2 when compared with references. Antifungal efficacies were also higher than commercial references, and the in vivo tolerance study confirmed the suitability for topical application, making CLT-NEs a great tool for clinical investigation of topical candidiasis treatments.

Mucoadhesive in situ gel formulation for vaginal delivery of clotrimazole: formulation, preparation, and in vitro/in vivo evaluation.

The purpose of this study was to develop a suitable mucoadhesive in situ gel formulation of clotrimazole (CLO) for the treatment of vaginal candidiasis. For this aim, the mixture of poloxamer (PLX) 407 and 188 were used to prepare in situ gels. Hydroxypropyl methylcellulose (HPMC) K100M or E50 was added to in situ gels in 0.5% ratio to improve the mucoadhesive and mechanical properties of formulations and to prolong the residence time in vaginal cavity. After the preparation of mucoadhesive in situ gels; gelation temperature/time, viscosity, mechanical, mucoadhesive, syringeability, spreadibility and rheological properties, in vitro release behavior, and anticandidal activities were determined. Moreover vaginal retention of mucoadhesive in situ gels was investigated with in vivo distribution studies in rats. Based on the obtained results, it was found that gels prepared with 20% PLX 407, 10% PLX 188 and 0.5% HPMC K100M/E50 might be suitable for vaginal administration of CLO. In addition, the results of in vivo distribution studies showed that gel formulations remained on the vaginal mucosa even 24 h after application. In conclusion, the mucoadhesive in situ gels of CLO would be alternative candidate for treatment of vaginal candidiasis since it has suitable gel properties with good vaginal retention.

Effect of chitosan coating on microemulsion for effective dermal clotrimazole delivery.

Clotrimazole (CTZ) is a broad spectrum antimycotic agent known to be very effective locally for the treatment of fungal skin infections. The aim of this study was to study the effect of chitosan-coated microemulsion (CME) for topical delivery of CTZ and also evaluate its in vitro antifungal efficacy, ex vivo permeation and retention ability on the skin surface. The pseudo-ternary phase diagrams were developed using clove oil as oil phase, Tween 80 and propylene glycol as surfactant and co-surfactant, respectively, and distilled water as aqueous phase. CME was prepared by the drop wise addition of chitosan solution to the optimized microemulsion. Physicochemical parameters (globule size, zeta potential, drug content, viscosity and pH) and in vitro release of CME were studied. The in vitro antifungal efficacy of CME and ME was studied by cup-plate method against Candida albicans. Ex vivo drug permeation study was also carried out in a modified diffusion cell, using rat skin. The developed CME displayed an average globule size less than 50 nm and a positive surface charge, acceptable physico-chemical behavior, and exhibited sustained drug release in in vitro study. In in vitro anti-fungal study, CME showed greater values of zone of inhibition as compared to ME due to its prolonged action as well as fungistatic nature of chitosan. In ex vivo study, CME showed better retention and sustained permeation property than ME due to the mucoadhesive property of chitosan. These results suggest that positively charged CMEs could be used as novel topical formulation for its ability to retain on the skin and its ability to sustain the release of the drug.

Polymeric Nanofiber/Antifungal Formulations Using a Novel Co-extrusion Approach.

We report the successful implementation of a novel melt co-extrusion process to fabricate ca. 1 µm diameter fibers of poly(caprolactone) (PCL) containing the antifungal compound clotrimazole in concentrations between 4 and 8 wt%. The process involves co-extrusion of a clotrimazole-loaded PCL along with poly(ethylene oxide) (PEO) as a co-feed, with subsequent removal of PEO to isolate PCL-clotrimazole fibers. In vitro tests of the clotrimazole-containing fibers against the fungus Aspergillus fumigatus, Candida albicans, and Trichophyton mentagrophytes strains demonstrated good antifungal activity which was maintained for more than 3 weeks. An in vivo study using a mouse model showed the lowest tissue fungal burden for PCL-clotrimazole when compared to a PCL-only patch and untreated controls. Comparative studies were conducted with clotrimazole-containing PCL fibers fabricated by electrospinning. Our data showed that the co-extruded, clotrimazole-containing fibers maintain activity for longer times vs. electrospun samples. This, coupled with the much higher throughput of the co-extrusion process vs. electrospinning, renders this new approach very attractive for the fabrication of drug-releasing polymer fibers.

Formulation and in vitro evaluation of carbopol 934-based modified clotrimazole gel for topical application.

The aim of present study was to enhance topical permeation of clotrimazole gel preparation by using various permeability enhancers such as coconut oil, pistachio oil and sodium lauryl sulphate (SLS). Clotrimazole gel preparations were prepared and optimized by using three factor, five level central composite design. A second-order polynomial equation was generated in order to estimate the effect of independent variables i.e. coconut oil (X1), pistachio oil (X2) and sodium lauryl sulphate (X3) at various dependent variables i.e. flux (Y1), lag time (Y2), diffusion coefficient (Y3), permeability coefficient (Y4), and input rate (Y5) of clotrimazole gel formulations. Ex vivo skin permeation study was performed through rat skin by using modified Franz diffusion cell system. Optimized formulation F8 exhibited highest flux 2.17 µg/cm2/min, permeability coefficient 0.0019 cm/min and input rate 1.543 µg/cm2/min, along with moderate lag time 77.27 min and diffusion coefficient 0.063 cm2/min, which is further supported by anti-fungal activity that exhibited more prominent zone of inhibition against Candida albicans, Aspergillus niger and Mucor. Thus, it can be concluded that permeation of clotrimazole gel was enhanced by various combination of coconut oil, pistachio oil and sodium lauryl sulphate but optimized formulation F8 containing 0.4 ml pistachio oil, 0.8 ml coconut oil and 0.04 g of SLS exhibited more pronounced and promising effect through rat skin.

Sub-lethal effects and bioconcentration of the human pharmaceutical clotrimazole in rainbow trout (Oncorhynchus mykiss).

The aim of this study was to characterize biomarker responses, haematological profiles, structural changes and uptake in juvenile rainbow trout exposed to clotrimazole (CLO) at three concentrations (0.01 - [lowest environmentally relevant concentration], 1.0 [highest environmentally relevant concentration] and 10 µg L(-1)) in a semi-static system over a period of 42 days. Antioxidant defence enzymes, which responded to CLO exposure, changed the oxidative stress status of cells, but no differences were observed in lipid peroxidation. Clotrimazole triggered a biphasic response of CYP3A-like activity in liver microsomes, which may indicate a detoxification process in the liver. Histopathological alterations were most pronounced in kidneys and testes in the group exposed to 10 µg L(-1). Structural changes in the kidney included tubulonephrosis and hyaline droplet degeneration in the tubular epithelial cells. The relative proportions of germ cells in testes were changed: The number of spermatozoa was reduced, and the spermatogonia and spermatocytes were increased. The highest CLO concentration was detected in fish liver (3710 ng per gram wet tissue) and kidney (4280 ng per gram wet tissue). Depuration half-life was estimated to be 72, 159, and 682 h in liver, muscle, and kidney, respectively. Taken together, these results provide valuable toxicological data on the effects of CLO on aquatic non-target organisms, which could be useful for further understanding of the potential risks in the real aquatic environment.

Uptake of azoles by lamb's lettuce (Valerianella locusta L.) grown in hydroponic conditions.

An uptake and translocation study of azole compounds was performed in lamb's lettuce (Valerianella locusta L.) grown in nutrient solution fortified with different azoles. Three azoles, (clotrimazole, fluconazole and propiconazole), which have different physico-chemical properties and are ubiquitous in the aquatic environment, were the compounds selected. An analytical method, based on matrix solid phase dispersion (MSPD) followed by LC-MS/MS determination, was developed to quantify these compounds in aqueous solution and in roots and leaves. The physicochemical properties of azoles are the main factors governing the uptake and plant accumulation. These azoles were detected in leaves indicating their transport within lamb's lettuce. Translocation from nutrient solution to the aerial part of lamb's lettuce was found to be highly dependent on the hydrophobicity of the azole. Clotrimazole accumulates in roots causing necrosis in roots and leaves, whereas fluconazole was the azole with the highest concentration in leaves without causing apparent phytotoxicity symptoms. The assessment of the levels of these azoles in leaves indicates that the risk for human health is negligible.

Comparison of the efficacy of a novel sustained release clotrimazole varnish and clotrimazole troches for the treatment of oral candidiasis.

OBJECTIVES: Candida albicans is a common fungal infection and is commensal in 40-65 % of healthy adults. The development and pharmacokinetics of a novel sustained release clotrimazole varnish (Clot-SRV) for topical oral use have been reported. The aim of this study was to compare the efficacy of this varnish with clotrimazole troche treatment of oral candidiasis. MATERIALS AND METHODS: Of the 12 patients with denture stomatitis treated for 14 days, six used Clot-SRV (study group) and six clotrimazole troches (control). The patients were instructed to use Clot-SRV (50 mg of clotrimazole) once a day, and the control group was instructed to use five troches of 10 mg clotrimazole/day. Microbiological samples were obtained from saliva, buccal mucosa, palate, and denture. The degree of erythema was recorded at three time points, and subjective opinions noted using a questionnaire. RESULTS: At the end of the study, the control group had relatively more cases of erythema on all examined surfaces; patients who applied the Clot-SRV had significantly lower levels of candida on the denture surfaces and in saliva, and had better compliance to the medication. CONCLUSIONS: The novel clotrimazole sustained release varnish may be an important part of a new protocol for oral candidiasis, with improved clinical outcomes.

Vaginal chitosan tablets with clotrimazole-design and evaluation of mucoadhesive properties using porcine vaginal mucosa, mucin and gelatine.

Topical administration of clotrimazole represents the common use therapy in the antimycotic genitourinary tract treatment. Due to the fast self-cleaning action of the vagina, commercially available vaginal dosage forms with clotrimazole cannot assure prolonged contact time with mucosa, therefore the main objective of this study was to develop a dosage form for vaginal administration of clotrimazole using chitosan-a biodegradable and biocompatible derivative of chitin. Tablets mucoadhesive properties were examined using texture analyser under the presence of porcine vaginal mucosa and two different models of adhesive layers- mucin gel and gelatine discs. In addition, friability, hardness, swelling behaviour, residence time, surface morphology of the performed tablets, the in vitro release profile of clotrimazole and clotrimazole release kinetics were determined. The release of clotrimazole from formulations with 25 or 40% of chitosan (F2 and F3) followed non Fickian diffusion through chitosan-gel layer and was retarded up to 6 h. Additionally, tablets F2 showed the best results in terms of mucoadhesive properties and appeared to be a good alternative to commercially available antimycotic vaginal dosage forms.

Polymeric microparticles-based formulation for the eradication of cutaneous candidiasis: development and characterization.

Cutaneous candidiasis is a common topical fungal infection which may be more prominent in patients associated with AIDS. It is usually treated by conventional formulations such as cream, gel, which show various adverse effects on skin along with systemic absorption. To overcome these drawbacks, various novel drug delivery systems have been explored. Poly(lactic-co-glycolic acid) (PLGA)-based microparticulate systems have shown good dermal penetration after topical application. Therefore, in the present study clotrimazole-loaded PLGA microspheres were prepared for targeted dermal delivery. Microspheres were prepared by using a single emulsification (oil-in-water, O/W) evaporation technique and characterized for different parameters. Prepared microparticulate systems were dispersed in Carbopol 934® gel and antifungal activity was carried out on experimentally induced cutaneous candidiasis in immunosuppressed guinea pigs. Particle size of optimized formulation was 2.9 µm along with 74.85% entrapment of drug. Skin retention studies revealed that drug accumulation in the skin was higher with microspheres gel as compared to marketed gel. Confocal microscopy of skin further confirmed penetration of microspheres up to 50 µm into the dermal region. In-vivo antifungal activity studies demonstrated that microsphere gel showed better therapeutic activity, lowest number of cfu/ml was recorded, as compared to marketed gel after 96 h of application. Based on the results of the study, it can be concluded that PLGA microparticles may be promising carriers to deliver clotrimazole intradermally for the treatment of invasive fungal infections.

Evaluation of the supply of antifungal medication for the treatment of vaginal thrush in the community pharmacy setting: a randomized controlled trial / Evaluación del suministro de medicación antifúngica para el tratamiento de la candidiasis vaginal en la farmacia comunitaria: ensayo controlado aleatorizado

Background: The Pharmaceutical Society of Australia have developed “guidance” for the supply of several medicines available without prescription to the general public. Limited research has been published assessing the effect of these guidelines on the provision of medication within the practice of pharmacy. Objectives: To assess appropriate supply of nonprescription antifungal medications for the treatment of vaginal thrush in community pharmacies, with and without a guideline. A secondary aim was to describe the assessment and counseling provided to patients when requesting this medication. Methods: A randomized controlled trial was undertaken whereby two simulated patients conducted visits to 100 randomly selected community pharmacies in a metropolitan region. A product-based request for fluconazole (an oral antifungal that has a guideline was compared to a product-based request for clotrimazole (a topical antifungal without a guideline). The same patient details were used for both requests. Outcome measures of the visits were the appropriateness of supply and referral to a medical practitioner. Results: Overall 16% (n=16) of visits resulted in an appropriate outcome; 10% (n=5) of fluconozaole requests compared with 22% (n=11) of clotrimazole requests (chi-square=2.68, p=0.10). There was a difference in the type of assessment performed by pharmacy staff between visits for fluconazole and clotrimazole. A request for clotrimazole resulted in a significant increase in frequency in regards to assessment of the reason for the request (chisquare= 8.57, p=0.003), symptom location (chisquare= 8.27, p=0.004), and prior history (chisquare= 5.09, p=0.02). Conclusions: Overall practice was poor, with the majority of pharmacies inappropriately supplying antifungal medication. New strategies are required to improve current practice of community pharmacies for provision of non-prescription antifungals in the treatment of vaginal thrush (AU)

Antecedentes: La Sociedad Farmacéutica de Australia ha desarrollado una “guía” para el suministro de varios medicamentos sin prescripción al público general. Se ha publicado poca investigación evaluando el efecto de estas guías sobre la provisión de medicación en la práctica de la farmacia. Objetivos: Evaluar el suministro apropiado de antifúngicos sin receta para el tratamiento de candidiasis vaginal en farmacias comunitarias, con y sin guía. Un objetivo secundario fue describir la evaluación y el consejo proporcionado a los pacientes cuando solicitaban esta medicación. Métodos: Se realizó un ensayo controlado aleatorizado donde dos pacientes simulados condujeron visitas a 100 farmacias comunitarias aleatoriamente seleccionadas en una región metropolitana. Se comparó una solicitud de un producto con fluconazol (antifúngico oral que tiene guía) con una solicitud de un producto con clotrimazol (un antifúngico tópico sin guía). Los mismos datos de los pacientes fueron usados en ambas solicitudes. Las medidas de resultados en las visitas fueron la adecuación del suministro y la remisión al médico. Resultados: Un total de un 16% (n=16) de las visitas produjeron resultados apropiados; 10% (n=5) de fluconazol comparadas con el 22% (n=11) de clotrimazol (chi-square= 2,68, p=0,10). Hubo una diferencia significativa en el tipo de evaluación realizada por el personal de la farmacia entre las visitas del fluconazol y del clotrimazol. La solicitud de clotrimazol produjo un aumento significativo en la frecuencia de la evaluación de la causa de la solicitud (chi-square = 8,57, p=0,003), localización de los síntomas (chi-square= 8,27, p=0,004), e historia previa (chi-square = 5,09, p=0,02). Conclusiones: En general la práctica fue pobre, con la mayoría de las farmacias suministrando inadecuadamente la medicación antifúngica. Se requieren nuevas estrategias para mejorar la práctica actual de las farmacias comunitarias en el suministro de antifúngicos sin receta para la candidiasis vaginal (AU)

Optimization of perfusate pH to improve microdialysis recovery of lipophilic compounds.

INTRODUCTION: Microdialysis (MD) allows sampling of compounds in-vivo from tissues' interstitial fluid. However, molecules insoluble at physiological pH have usually extremely low recovery. The addition of albumin to the perfusate or the use of isotonic lipoemulsion improves recovery of these molecules although it requires a cleaning step before HPLC analysis. This study investigates the possibility of improving the MD recovery of compounds insoluble at physiological pH but soluble at a different pH. The probe is perfused with an isotonic solution adjusted to pH values at which the compound has maximum solubility. Ketoconazole (KTC), clotrimazole (CLT) and tretinoin (TTN) were selected as model drugs because they are almost insoluble at pH 7.4 but soluble at pH 4 for KTC and CTL; and at pH 9 for TTN. METHODS: Linear microdialysis probes were used to collect KTC, CLT or TTN from a standard solution of the compounds. Probes were perfused with 0.01 M pH 7.4 isotonic buffer solution (1) without or (2) with 5% Bovine Serum Albumin (BSA); or (3) with 20% isotonic lipoemulsion; or (4) with 0.01 M pH 4 isotonic buffer solution for KTC and CLT or 0.01 M pH 9 isotonic buffer solution for TTN. The method was then tested in-vivo, in rabbit skin, to assess the skin tolerance to the non-physiological perfusates and to monitor KTC and TTN delivery from commercial cream products. RESULTS: In-vitro, the optimized-pH perfusate increased MD recovery significantly (P<0.001): 6.9 (KTC), 8.3 (CLT), and 2.0 (TTN) times compared to the physiological pH and 1.4 and 1.2 compared to the BSA and lipoemulsion respectively. No evidence of irritation or edema was observed in-vivo. However, KTC and TTN were not detected in-vivo with any of the modified perfusate tested. DISCUSSION: These findings show that the optimized-pH perfusate effectively increases the in-vitro microdialysis recovery of KTC, CLT and TTN and that it is well tolerated in-vivo. However, the compounds tested (KTC and TTN) could not be detected in-vivo.

Inclusion complex effect on the bioavailability of clotrimazole from poloxamer-based solid suppository.

To study the effect of ß-cyclodextrin (ßCD) inclusion complex on the bioavailability of clotrimazole from poloxamer-based suppository, formulations composed of P 188, propylene glycol and different molar ratio of clotrimazole-ßCD inclusion complex were prepared. Clotrimazole (1%) has been formulated in a suppository using the thermo sensitive polymer P188 (70%) together with propylene glycol (30%). To increase its aqueous solubility, clotrimazole was incorporated as its inclusion complex at various molar ratios with ßCD (1:0.25, 1:0.5, 1:1, and 1:2). The inclusion complex was characterized by differential scanning calorimetry (DSC), XRD and phase solubility studies. It was observed that the complexation with ßCD, particularly at high molar ratio (F3 (1:1) and F4 (1:2)) decreased the release profile of clotrimazole considerably. However, suppositories containing inclusion complex at low molar ratio (F1 (1:0.25) and F2 (1:0.5)) showed excellent release profile compared to control formulation. In vivo study in rats at 15 mg/Kg dose showed that the F1 and F2 (82.39 ± 15.40 and 67.05 ± 8.79, respectively) significantly increased the AUC compared to that of F3 (41.48 ± 11.51), F4 (23.34 ± 8.37) and control (46.7 ± 7.87) suppositories. Thus, the suppositories containing inclusion complexes prepared at low drug to ßCD molar ratio (F1) could be a potential suppository formulation to increase the bioavailability of hydrophobic drugs such as clotrimazole.

Optimization of 4-aminoquinoline/clotrimazole-based hybrid antimalarials: further structure-activity relationships, in vivo studies, and preliminary toxicity profiling.

Despite recent progress in the fight against malaria, the emergence and spread of drug-resistant parasites remains a serious obstacle to the treatment of infections. We recently reported the development of a novel antimalarial drug that combines the 4-aminoquinoline pharmacophore of chloroquine with that of clotrimazole-based antimalarials. Here we describe the optimization of this class of hybrid drug through in-depth structure-activity relationship studies. Antiplasmodial properties and mode of action were characterized in vitro and in vivo, and interactions with the parasite's 'chloroquine resistance transporter' were investigated in a Xenopus laevis oocyte expression system. These tests indicated that piperazine derivatives 4b and 4d may be suitable for coadministration with chloroquine against chloroquine-resistant parasites. The potential for metabolism of the drugs by cytochrome P450 was determined in silico, and the lead compounds were tested for toxicity and mutagenicity. A preliminary pharmacokinetic analysis undertaken in mice indicated that compound 4b has an optimal half-life.

Clotrimazole and enilconazole distribution within the frontal sinuses and nasal cavity of nine dogs with sinonasal aspergillosis.

OBJECTIVES: Multiple topical treatments are often required for clinical cure of mycotic rhinosinusitis in dogs. The objective of this study was to describe the distribution and retention of enilconazole and clotrimazole solutions using a temporary trephination protocol. METHODS: Nine client-owned dogs diagnosed with mycotic rhinosinusitis between March 2008 and December 2009 were prospectively enrolled and were sequentially allocated to receive treatment with either clotrimazole (1% in polyethylene glycol) or enilconazole (10% solution), after imaging and rhinoscopic assessment. Both frontal sinuses were trephined, debrided and flushed with saline. Infusion was administered via frontal sinuses with dogs in sternal recumbency and computed tomography (CT) performed 5 minutes after completion. Distribution was scored 1 to 4 at the canine tooth, premolar 4, cribriform plate and frontal sinus on both sides, for a maximum score of 32. RESULTS: Distribution of antifungal agents to all regions of the nasal cavity and frontal sinuses was achievable, but varied considerably. Retention was poor in 10 of 18 regions assessed. CLINICAL SIGNIFICANCE: Distribution of antifungal agents within the frontal sinuses is achievable using temporary trephination; however, distribution is variable and retention is often poor.

Distribution and persistence of topical clotrimazole after sinus infusion in normal canine cadavers.

OBJECTIVES: To determine the in vitro persistence of clotrimazole 1% cream in the canine frontal sinus and to evaluate the distribution of clotrimazole solution over the sino-nasal mucosa using a previously described surgical treatment protocol for canine nasal aspergillosis. METHODS: Two canine skulls were used to monitor the persistence of clotrimazole cream in the lateral frontal sinus at 37°C. The distribution of irrigation solution around the frontal sinus compartments and nasal cavity was determined using six canine cadaver heads by trephining either the lateral or both the lateral and rostral compartments of the frontal sinus. Stain was added to the sinus irrigation solution before visually inspecting the sagittally sectioned heads. RESULTS: Clotrimazole cream persisted in the frontal sinus for at least 96 hours. The nasal cavity mucosa was completely stained in 8 of 12 sides and almost completely stained in the remaining 4 of 12 sides. Flushing irrigation solution through the lateral compartment of the frontal sinus resulted in inadequate staining of the rostral compartment but medicating both the lateral and rostral compartments resulted in complete coating of all frontal sinus mucosa in eight of eight sides. CLINICAL SIGNIFICANCE: Clotrimazole cream has the potential to be retained in the frontal sinus for several days and is distributed effectively in normal canine cadavers. Medicating both the rostral and lateral compartments of the frontal sinus may be indicated in some clinical cases.

Bioequivalence of topical clotrimazole formulations: an improved tape stripping method.

PURPOSE: Investigations were carried out to assess the use of tape stripping (TS) for the determination of bioequivalence of topical products containing 1% clotrimazole. METHODS: The study design involved the establishment of an appropriate application time, which was determined by conducting a dose duration study. Subsequently, two bioequivalence studies were conducted: i) using the brand (Canesten Topical - 1% clotrimazole cream) as both the test and the reference product and ii) comparing Canesten cream with a gel product containing the same concentration of clotrimazole (1%). Each tape strip was individually analyzed for clotrimazole content using an HPLC method and Transepidermal Water Loss (TEWL) measurements were used to normalize the stratum corneum thicknesses between subjects. RESULTS: The results of the TS investigations showed that, if the study is sufficiently powered, tape stripping may be used to determine bioequivalence according to the conventional bioequivalence limits of 0.8-1.25, as well as detect formulation differences between different clotrimazole products. CONCLUSIONS: The data from this study provided compelling evidence that tape stripping has the necessary attributes and potential to be used as a tool for the bioequivalence assessment of topical clotrimazole and/or other topical formulations, thereby circumventing the need to undertake expensive and time-consuming clinical trials for such products. This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.