Topical Amphotericin B Semisolid Dosage Form for Cutaneous Leishmaniasis: Physicochemical Characterization, Ex Vivo Skin Permeation and Biological Activity

Caspofungin formulations for buccal and sublingual mucosae anti-fungal infections: physicochemical characterization, rheological analysis, release and ex vivo permeability profiles

AIM

Oral candidiasis is often challenging due to limited effectiveness of topical treatments. This study aimed to develop novel caspofungin formulations for administration onto the oral mucosa to enhance drug retention and efficacy.

METHOD

Five caspofungin (2%, w/v) formulations were developed to assess their permeability, retention and mucoadhesiveness. Ex vivo permeability assays were performed on buccal and sublingual mucosae, and histological analyses conducted to evaluate tissue tolerance.

RESULTS

Formulation composed of chitosan demonstrated the highest retention in both buccal (5183.24 ± 587.32 µg/cm2) and sublingual (1090.72 ± 110.26 µg/cm2) mucosae. Other formulations exhibited significantly lower retention, ranging from 7.53 ± 0.81 to 1852.10 ± 193.24 µg/cm2 in buccal mucosa and 1.64 ± 0.14 to 317.74 ± 31.78 µg/cm2 in sublingual mucosa. Chitosan-based formulation exhibited the highest mucoadhesive strength, with values of 5179.05 ± 31.99 mN/cm2 for buccal and 7026.10 ± 123.41 mN/cm2 for sublingual mucosae, and also superior extensibility, which facilitates application in the oral cavity. All formulations showed antifungal activity against Candida spp., and histological analyses revealed minor epithelial alterations.

CONCLUSION

The developed formulations offer distinct advantages for treating oral candidiasis, with chitosan formulation emerging as the most promising due to its superior retention, mucoadhesion force, and spreadability, making it a potential candidate for further clinical investigation.

Healing Potential of the Marine Polysaccharides Carrageenan and Ulvan on Second-Degree Burns

The treatment of second-degree burn wounds presents a significant clinical challenge, often characterized by prolonged healing times and risk of complications. In this study, the wound healing potential of bioactive marine sulfated polysaccharides ulvan and carrageenan formulated in gels at concentrations of 1.5%, 5.0%, and 10% w/w was evaluated. Hairless female SKH-hr2 mice (n = 7 per treatment) with burn-inflamed skin were treated with the polysaccharide-based gels, and the therapeutic efficacy was assessed using a comprehensive array of evaluation methods, including a histopathological analysis, clinical observation, photo-documentation, an image analysis, an evaluation of biophysical skin parameters, and FT-IR spectroscopy. Our findings indicate that the 10% w/w carrageenan gel exhibited significant enhancement in wound healing, particularly in the early stages of the healing process. This was evidenced by the restoration of the α-helix structure of collagen and the configuration of glycosaminoglycans, as demonstrated by FT-IR absorption bands of the skin both in vivo and ex vivo. Furthermore, the 5% w/w ulvan gel also demonstrated notable efficacy in promoting wound healing, particularly in the later stages of the healing process. These results suggest that carrageenan and ulvan gels hold promise for improving the efficiency of wound healing in second-degree burn wounds. Our study contributes to the understanding of the therapeutic potential of marine polysaccharides and provides insights into their mechanism of action in promoting wound healing.

In Vivo Evaluation of Sepigel-Based Meglumine Antimoniate and Amphotericin B for Cutaneous Leishmaniasis Treatment

Cutaneous leishmaniasis (CL) poses a significant public health concern in endemic regions due to its increasing prevalence and substantial impact on affected individuals. This disease is primarily caused by the Leishmania protozoa, which are transmitted through insect bites, and it manifests as a range of symptoms, from self-healing lesions to severe disfigurement. Current treatments, which often involve the parenteral administration of antimonials, face challenges such as poor compliance and adverse effects. This study investigates the efficacy of topical formulations containing meglumine antimoniate (MA) and amphotericin B (AmB), using Sepigel as an excipient, for treating CL. In the in vivo study, BALB/c mice infected with L. amazonensis developed lesions at the injection site five weeks post-infection. Subsequently, the mice were divided into eight groups: untreated mice, mice treated orally with miltefosine, mice treated intraperitoneally with MA, and mice treated topically with 15%, 22.5%, and 30% MA-Sepigel, as well as those treated with AmB-Sepigel. Treatments were applied daily for two weeks, and the results revealed a significant reduction in lesion size and parasite burden following topical application, particularly with the AmB-Sepigel formulations and 30% MA-Sepigel. Additionally, Sepigel-based treatments demonstrated improved patient compliance and reduced toxicity compared to systemic therapies. These findings underscore the potential of Sepigel-based formulations as a promising alternative for CL treatment. They offer enhanced efficacy and tolerability, while reducing the systemic toxicity associated with conventional therapies.

Nanocomposite Gels Loaded with Flurbiprofen: Characterization and Skin Permeability Assessment in Different Skin Species

Nanocomposite gels consist of nanoparticles dispersed in a gel matrix. The main aim of this work was to develop nanocomposite gels for topical delivery of Flurbiprofen (FB) for humans and farm animals. Nanocomposite gels were prepared stemming from nanoparticles (NPs) freeze-dried with two different cryoprotectants, D-(+)-trehalose (NPs-TRE) and polyethylene glycol 3350 (NPs-PEG), sterilized by gamma (γ) irradiation, and gelled with Sepigel® 305. Nanocomposite gels with FB-NPs-TRE and FB-NPs-PEG were physiochemically characterized in terms of appearance, pH, morphological studies, porosity, swelling, degradation, extensibility, and rheological behavior. The drug release profile and kinetics were assessed, as well as, the ex vivo permeation of FB was assessed in human, porcine and bovine skin. In vivo studies in healthy human volunteers were tested without FB to assess the tolerance of the gels with nanoparticles. Physicochemical studies demonstrated the suitability of the gel formulations. The ex vivo skin permeation capacity of FB-NPs nanocomposite gels with different cryoprotectants allowed us to conclude that these formulations are suitable topical delivery systems for human and veterinary medicine. However, there were statistically significant differences in the permeation of each formulation depending on the skin. Results suggested that FB-NPs-PEG nanocomposite gel was most suitable for human and porcine skin, and the FB-NPs-TRE nanocomposite gel was most suitable for bovine skin.

Developing nanosize carrier systems for Amphotericin-B: A review on the biomedical application of nanoparticles for the treatment of leishmaniasis and fungal infections

New formulations of Amphotericin-B (Am-B), the most popular therapeutic drug for many human infections such as parasitic and fungal pathogens, are safe, economical, and effective in the world. Several newly designed carrier systems for Am-B can also be considered orally with sufficient gastrointestinal permeability and good solubility. However, the clinical application of several new formulations of Am-B with organ cytotoxicity, low bioavailability, high costs, and technical problems have caused some issues. Therefore, more attention and scientific design are required to progress safe and effective drug delivery systems. Currently, the application of nano-based technology and nanomaterials in the advancement of drug delivery systems exhibits promising outcomes to cure many human systemic infections. Designing novel drug delivery systems including solid lipid nanostructured materials, lipo-polymersomes, drug conjugates and microneedles, liposomes, polymer and protein-based nanostructured materials, dendrimers, emulsions, mixed micelles, polymeric micelles, cyclodextrins, nanocapsules, and nanocochleate for Am-B has many advantages to reducing several related issues. The unique properties of nanostructured particles such as proper morphology, small size, surface coatings, and, electrical charge, permit scientists to design new nanocomposite materials against microorganisms for application in various human diseases. These features have made these nanoparticles an ideal candidate for drug delivery systems in clinical approaches to cure a number of human disorders and currently, several therapeutic nanostructured material formulations are under different stages of clinical tests. Hence, this scientific paper mainly discussed the advances in new formulations of Am-B for the treatment of human systemic infections and related clinical tests.

Efficacy of Apremilast Gels in Mouse Model of Imiquimod-Induced Psoriasis Skin Inflammation

Apremilast (APM) is a novel drug for the treatment of psoriasis and psoriatic arthritis. APM is a phosphodiesterase 4 (PDE4) inhibitor, raising intracellular cAMP levels and thereby decreasing the inflammatory response by modulating the expression of TNF-α, IL-17, IL-23, and other inflammatory cytokines. The goal of this study is to develop APM gels as a new pharmaceutical formulation for the treatment of topical psoriasis. APM was solubilized in Transcutol-P and incorporated into Pluronic F127, Sepigel, and carbomer bases at different proportions. All formulations were characterized physiochemically. A biopharmaceutical study (release profile) was performed, and ex vivo permeation was evaluated using a human skin model. A toxicity assay was carried out on the HaCaT cell line. A mouse model of imiquimod-induced psoriasis skin inflammation was carried out to determine its efficacy by histological analysis, RNA extraction, and RT-qPCR assays. APM gel formulations showed good physicochemical characteristics and a sustained release profile. There was no permeation of any gel measured through human skin, indicating a high retained amount of APM on the skin. Cell viability was greater than 80% at most dilution concentrations. APM gels treated the psoriasis mouse model, and it shows a reduction in the proinflammatory cytokines (IL-8, IL-17A, IL-17F, and IL-23). APM gels could be a new approach for the treatment of topical psoriasis.

Caspofungin-Loaded Formulations for Treating Ocular Infections Caused by Candida spp

Fungal keratitis causes corneal blindness worldwide. The treatment includes antibiotics, with Natamycin being the most commonly used; however, fungal keratitis is difficult to treat, so alternative therapies are needed. In situ gelling formulations are a promising alternative; this type of formulation has the advantages of eye drops combined with the advantages of ointments. This study was designed to develop and characterize three formulations containing 0.5% CSP: CSP-O1, CSP-O2, and CSP-O3. CSP is an antifungal drug that acts against a diverse variety of fungi, and Poloxamer 407 (P407) is a polymer of synthetic origin that is able to produce biocompatible, biodegradable, highly permeable gels and is known to be thermoreversible. Short-term stability showed that formulations are best stored at 4 °C, and rheological analysis showed that the only formulation able to gel in situ was CSP-O3. In vitro release studies indicated that CSP-O1 releases CSP most rapidly, while in vitro permeation studies showed that CSP-O3 permeated the most. The ocular tolerance study showed that none of the formulations caused eye irritation. However, CSP-O1 decreased the cornea's transparency. Histological results indicate that the formulations are suitable for use, with the exception of CSP-O3, which induced slight structural changes in the scleral structure. All formulations were shown to have antifungal activity. In view of the results obtained, these formulations could be promising candidates for use in the treatment of fungal keratitis.

Gel Formulations with an Echinocandin for Cutaneous Candidiasis: The Influence of Azone and Transcutol on Biopharmaceutical Features

Caspofungin is a drug that is used for fungal infections that are difficult to treat, including invasive aspergillosis and candidemia, as well as other forms of invasive candidiasis. The aim of this study was to incorporate Azone in a caspofungin gel (CPF-AZ-gel) and compare it with a promoter-free caspofungin gel (CPF-gel). An in vitro release study using a polytetrafluoroethylene membrane and ex vivo permeation into human skin was adopted. The tolerability properties were confirmed by histological analysis, and an evaluation of the biomechanical properties of the skin was undertaken. Antimicrobial efficacy was determined against Candida albicans, Candida glabrata, Candida parapsilosis, and Candida tropicalis. CPF-AZ-gel and CPF-gel, which had a homogeneous appearance, pseudoplastic behavior, and high spreadability, were obtained. The biopharmaceutical studies confirmed that caspofungin was released following a one-phase exponential association model and the CPF-AZ gel showed a higher release. The CPF-AZ gel showed higher retention of caspofungin in the skin while limiting the diffusion of the drug to the receptor fluid. Both formulations were well-tolerated in the histological sections, as well as after their topical application in the skin. These formulations inhibited the growth of C. glabrata, C. parapsilosis, and C. tropicalis, while C. albicans showed resistance. In summary, dermal treatment with caspofungin could be used as a promising therapy for cutaneous candidiasis in patients that are refractory or intolerant to conventional antifungal agents.

Polyene macrolide antibiotic nanoemulsion: a proposal for the treatment of cutaneous leishmaniasis

Leishmaniasis is a neglected tropical disease that requires timely and inexpensive treatment. For this purpose, a nanoemulsion with a polyene macrolide antibiotic, or amphotericin B (NE-AmB), was developed. This study quantified the amount of drug permeated and retained in intact and lacerated human skin, simulating cutaneous leishmaniasis (CL) processes. Toxicity in macrophage and keratinocyte cell lines, activity against promastigotes and amastigotes of Leishmania tropica, in vivo irritant activity, and histological evidence was evaluated. Results. The amount of drug retained in intact and damaged skin was 750.18 ± 5.43 and 567.97 ± 8.64 µg/g/cm2, respectively. There was no permeation. No apparent toxic effect was observed in HaCaT cell lines. The IC50 of NE-AmB found for promastigotes and amastigotes was 0.26 ± 0.09 and 0.37 ± 0.05 µg/mL, respectively. NE without AmB did show antiparasitic activity. The formulation showed lower IC50 values on both parasite stages than the AmB solution. There was no skin irritation, and histology showed skin improvement with treatment. We suggest that this NE-AmB may be a candidate for in vivo studies in CL patients. Keywords. Leishmaniasis, Amphotericin B, ex vivo permeation studies, in vitro cytotoxicity, in vitro leishmanicidal activity, Draize test, histology.

Comparative Study of Donepezil-Loaded Formulations for the Treatment of Alzheimer's Disease by Nasal Administration

Alzheimer's disease is characterized by a progressive deterioration of neurons resulting in a steady loss of cognitive functions and memory. Many treatments encounter the challenge of overcoming the blood-brain barrier, thus the intranasal route is a non-invasive effective alternative that enhances the drug delivery in the target organ-the brain-and reduces the side effects associated with systemic administration. This study aimed at developing intranasal gels of donepezil as an approach to Alzheimer's disease. Three different gels were elaborated and characterized in terms of pH, morphology, gelation temperature, rheology, and swelling. An in vitro release study and an ex vivo permeation in porcine nasal mucosa were conducted on Franz diffusion cells. The tolerability of the formulations was determined by the cytotoxicity in human nasal cells RPMI 2650. Results showed that pluronic gels exhibit the higher release rate and enhanced permeation compared to chitosan gel. Moreover, the combination of Pluronic F-127 and Transcutol® P exerted a synergic effect on the permeation of donepezil through the nasal mucosa. The resulting gels showed suitable tolerance in the RPMI 2650 cell line and physicochemical characteristics for intranasal delivery, and thus gel formulations administered by nasal mucosa could be an alternative strategy to improve the bioavailability of donepezil.

Cutaneous/Mucocutaneous Leishmaniasis Treatment for Wound Healing: Classical versus New Treatment Approaches

Cutaneous leishmaniasis (CL) and mucocutaneous leishmaniasis (ML) show clinical spectra that can range from a localized lesion (with a spontaneous healing process) to cases that progress to a generalized systemic disease with a risk of death. The treatment of leishmaniasis is complex since most of the available drugs show high toxicity. The development of an effective topical drug formulation for CL and ML treatment offers advantages as it will improve patient’s compliance to the therapy given the possibility for self-administration, as well as overcoming the first pass metabolism and the high costs of currently available alternatives. The most common dosage forms include solid formulations, such as membranes and semi-solid formulations (e.g., ointments, creams, gels, and pastes). Topical treatment has been used as a new route of administration for conventional drugs against leishmaniasis and its combinations, as well as to exploit new substances. In this review, we discuss the advantages and limitations of using topical drug delivery for the treatment of these two forms of leishmaniasis and the relevance of combining this approach with other pharmaceutical dosage forms. Emphasis will also be given to the use of nanomaterials for site-specific delivery.

Dual treatment of cutaneous leishmaniasis with topical amphotericin B and photodynamic therapy in a pediatric patient

Cutaneous leishmaniasis is a parasitic infection that can result in scarring, contributing to significant morbidity when a cosmetically sensitive area is involved. We report a case of a 13-year-old boy with cutaneous leishmaniasis involving the face and arm. He was treated with a combination of photodynamic therapy as well as topical amphotericin with a cosmetically satisfying outcome. This combination of noninvasive treatment regimens has not been reported to our knowledge and merits further study in the pediatric population.

Antileishmanial Agents Co-loaded in Transfersomes with Enhanced Macrophage Uptake and Reduced Toxicity

The prime objective of this study was to develop amphotericin B (AMB) and rifampicin (RIF) co-loaded transfersomal gel (AMB-RIF co-loaded TFG) for effective treatment of cutaneous leishmaniasis (CL). AMB-RIF co-loaded TF was prepared by the thin-film hydration method and was optimized based on particle size, polydispersity index (PDI), zeta potential, entrapment efficiency (%EE), and deformability index. Similarly, AMB-RIF co-loaded TFG was characterized in terms of rheology, spread ability, and pH. In vitro, ex vivo, and in vivo assays were performed to evaluate AMB-RIF co-loaded TF as a potential treatment option for CL. The optimized formulation had vesicles in nanosize range (167 nm) with suitable PDI (0.106), zeta potential (- 19.05 mV), and excellent %EE of RIF (66%) and AMB (85%). Moreover, it had appropriate deformability index (0.952). Additionally, AMB-RIF co-loaded TFG demonstrated suitable rheological behavior for topical application. AMB-RIF co-loaded TF and AMB-RIF co-loaded TFG showed sustained release of the incorporated drugs as compared to AMB-RIF suspension. Furthermore, RIF permeation from AMB-RIF co-loaded TF and AMB-RIF co-loaded TFG was enhanced fivefold and threefold, whereas AMB permeation was enhanced by eightfold and 6.6-fold, respectively. The significantly different IC₅₀, higher CC₅₀, and FIC₅₀ (p < 0.5) showed synergistic antileishmanial potential of AMB-RIF co-loaded TF. Likewise, reduced lesion size and parasitic burden in AMB-RIF co-loaded TF-treated mouse group further established the antileishmanial effect of the optimized formulation. Besides, AMB-RIF co-loaded TFG showed a better safety profile. This study concluded that TFG may be a suitable carrier for co-delivery of AMB-RIF when administered topically for the treatment of CL.

Biophysical and ultrasonographic changes of acute Old World cutaneous leishmaniasis skin lesions in comparison with uninvolved skin: A possible tool for non-invasive early detection and treatment outcome assessment

BACKGROUND

Cutaneous leishmaniasis (CL) is a skin disease caused by intracellular protozoa, which is endemic in Iran. The goal of this study was to compare biophysical characteristics in CL lesions with uninvolved skin.

METHODS

Stratum corneum hydration, transepidermal water loss, surface friction, pH, sebum, melanin, erythema, temperature, elasticity parameters (R0, R2, and R5), thickness and echo-density of epidermis and dermis were measured on the active erythematous indurated part of a typical CL lesion in 20 patients, and compared with the same location on the other side of the body as control. Paired t- test was used for statistical analyses and a P<0.05 was considered significant.

RESULTS

Melanin content, R2 and echo-density of dermis were significantly lower, whereas transepidermal water loss, friction index, pH, erythema index, temperature and the thickness of dermis were significantly higher in CL lesions. There was no significant difference in stratum corneum hydration, sebum, R0, R5, thickness of epidermis and density of epidermis between CL and normal skin.

CONCLUSIONS

CL lesions are characterized by certain changes in biophysical and ultrasonographic properties, which are mostly correlated with histological features. These changes are likely to be useful in the non-invasive early detection of CL and also as treatment outcome measures for clinical trials of new treatment modalities for CL in the future. This article is protected by copyright. All rights reserved.

Enhanced Transdermal Delivery of Pranoprofen Using a Thermo-Reversible Hydrogel Loaded with Lipid Nanocarriers for the Treatment of Local Inflammation

A biocompatible topical thermo-reversible hydrogel containing Pranoprofen (PF)-loaded nanostructured lipid carriers (NLCs) was studied as an innovative strategy for the topical treatment of skin inflammatory diseases. The PF-NLCs-F127 hydrogel was characterized physiochemically and short-time stability tests were carried out over 60 days. In vitro release and ex vivo human skin permeation studies were carried out in Franz diffusion cells. In addition, a cytotoxicity assay was studied using the HaCat cell line and in vivo tolerance study was performed in humans by evaluating the biomechanical properties. The anti-inflammatory effect of the PF-NLCs-F127 was evaluated in adult male Sprague Daw-ley^® rats using a model of inflammation induced by the topical application of xylol for 1 h. The developed PF-NLCs-F127 exhibited a heterogeneous structure with spherical PF-NLCs in the hydrogel. Furthermore, a thermo-reversible behaviour was determined with a gelling temperature of 32.5 °C, being close to human cutaneous temperature and thus favouring the retention of PF. Furthermore, in the ex vivo study, the amount of PF retained and detected in human skin was high and no systemic effects were observed. The hydrogel was found to be non-cytotoxic, showing cell viability of around 95%. The PF-NLCs-F127 is shown to be well tolerated and no signs of irritancy or alterations of the skin's biophysical properties were detected. The topical application of PF-NLCs-F127 hydrogel was shown to be efficient in an inflammatory animal model, preventing the loss of stratum corneum and reducing the presence of leukocyte infiltration. The results from this study confirm that the developed hydrogel is a suitable drug delivery carrier for the transdermal delivery of PF, improving its dermal retention, opening the possibility of using it as a promising candidate and safer alternative to topical treatment for local skin inflammation and indicating that it could be useful in the clinical environment.

New Formulations Loading Caspofungin for Topical Therapy of Vulvovaginal Candidiasis

Vulvovaginal candidiasis (VVC) poses a significant problem worldwide affecting women from all strata of society. It is manifested as changes in vaginal discharge, irritation, itching and stinging sensation. Although most patients respond to topical treatment, there is still a need for increase the therapeutic arsenal due to resistances to anti-infective agents. The present study was designed to develop and characterize three hydrogels of chitosan (CTS), Poloxamer 407 (P407) and a combination of both containing 2% caspofungin (CSP) for the vaginal treatment of VVC. CTS was used by its mucoadhesive properties and P407 was used to exploit potential advantages related to increasing drug concentration in order to provide a local effect. The formulations were physically, mechanically and morphologically characterized. Drug release profile and ex vivo vaginal permeation studies were performed. Antifungal efficacy against different strains of Candida spp. was also evaluated. In addition, tolerance of formulations was studied by histological analysis. Results confirmed that CSP hydrogels could be proposed as promising candidates for the treatment of VVC.

Development of a Topical Amphotericin B and Bursera graveolens Essential Oil-Loaded Gel for the Treatment of Dermal Candidiasis

The higher molecular weight and low solubility of amphotericin B (AmB) hinders its topical administration. The aim of this study was to incorporate Bursera graveolens essential oil into an AmB topical gel (AmB + BGEO gel) in order to promote the diffusion of the drug through the skin in the treatment of cutaneous candidiasis. AmB + BGEO gel formulation was determined using a factorial experiment. Physical and chemical parameters, stability, in vitro release profile and ex vivo permeation in human skin were evaluated. In vitro antimicrobial activity was studied using strains of C. albicans, C. glabrata and C. parapsilosis. The tolerability was evaluated using in vitro and in vivo models. AmB + BGEO gel presented appropriate characteristics for topical administration, including pH of 5.85, pseudoplastic behavior, optimal extensibility, as well as high stability and acceptable tolerability. In vitro release studies showed that the formulation releases the drug following a Boltzmann sigmoidal model. Finally, AmB + BGEO gel exhibited higher amount of drug retained inside the skin and lower Minimum Inhibitory Concentration than a formulation sans essential oil. Therefore, these results suggest that the incorporation of B. graveolens essential oil in the formulation could be used as strategy to promote a local effect in the treatment of cutaneous candidiasis.

Nano Based Approach for the Treatment of Neglected Tropical Diseases

Neglected tropical diseases (NTDs) afflict more than one billion peoples in the world’s poorest countries. The World Health Organization (WHO) has recorded seventeen NTDs in its portfolio, mainly caused by bacterial, protozoal, parasitic, and viral infections. Each of the NTDs has its unique challenges on human health such as interventions for control, prevention, diagnosis, and treatment. Research for the development of new drug molecules against NTDs has not been undertaken by pharmaceutical industries due to high investment and low-returns, which results in limited chemotherapeutics in the market. In addition, conventional chemotherapies for the treatment of NTDs are unsatisfactory due to its low efficacy, increased drug resistance, short half-life, potential or harmful fatal toxic side effects, and drug incompetence to reach the site of parasite infection. In this context, active chemotherapies are considered to be re-formulated by overcoming these toxic side effects via a tissue-specific targeted drug delivery system. This review mainly emphasizes the recent developments of nanomaterial-based drug delivery systems for the effective treatment of NTDs especially sleeping sickness, leishmaniasis, chagas disease, soil-transmitted helminthiasis, african trypanosomiasis and dengue. Nanomaterials based drug delivery systems offer enhanced and effective alternative therapy through the re-formulation approach of conventional drugs into site-specific targeted delivery of drugs.

Preclinical safety evaluation of amphotericin A21: A novel antifungal

Safety studies are essential in drug development. This study evaluates the safety of Amphotericin A21 (AmB-A21), a derivative of amphotericin B with antifungal therapeutic potential. We performed a chronic toxicity study, a targeted organ study and a dermal irritation test. To evaluate chronic toxicity, 18 male adult rats were treated orally with AmB-21 (2 mg/kg) for 26 weeks. The effects on body-weight and animal health were measured, and haematological, clinical chemistry and histopathological tests were conducted on various organs. In the target organ toxicity study, male adult rats received a daily oral dose of AmB-21 (2 mg/kg) for 6 and 17 weeks; testicle histology and testosterone levels were then evaluated. For the dermal irritation study, AmB-21 (200 and 1000 mg/kg) was placed on the skin of adult male rabbits; macroscopic and microscopic studies, as well as haematological and clinical chemistry tests were then conducted. The chronic toxicity study revealed that AmB-21 caused testicle damage, and the testicle-targeted study showed structural alterations and changes in testosterone levels at 17 weeks. However, these alterations were no longer observed 8 weeks after discontinuation of treatment, and the testes showed very similar characteristics to those in the control group. The dermal irritation study showed skin thickening and reddening in rabbits treated with 2000 mg of AmB-A21 after 14 days of exposure. This same group also showed changes in liver enzymes, renal parameters and platelet levels. Based on our results, we consider AmB-21 to be a potential candidate for safe, long-term antifungal treatment given its reduced side effects.

Pharmacokinetics and pharmacodynamics in the treatment of cutaneous leishmaniasis - challenges and opportunities

Pharmacological efficacy is obtained when adequate concentrations of a potent drug reach the target site. In cutaneous leishmaniasis, a heterogeneous disease characterised by a variety of skin manifestations from simple nodules, skin discoloration, plaques to extensive disseminated forms, the parasites are found in the dermal layers of the skin. Treatment thus involves the release of the active compound from the formulation (administered either topically or systemically), it's permeation into the skin, accumulation by the local macrophages and further transport into the phagolysosome of the macrophage. The pharmacodynamic activity of a drug against the parasite is relatively straight forward to evaluate both in vivo and in vitro. The pharmacokinetic processes taking place inside the skin are more complex to elucidate due to the multi-lamellar structure of the skin, heterogeneous distribution of drugs within the tissue, the difficulty of accessing the site of infection complicating sampling and the lack of surrogate markers reflecting the activity of a drug in the skin. This review will discuss the difficulties encountered when investigating drug distribution, PK PD relationships and efficacy in the skin with a focus on cutaneous leishmaniasis treatment.

A clioquinol-containing Pluronic® F127 polymeric micelle system is effective in the treatment of visceral leishmaniasis in a murine model

A clioquinol (ICHQ)-containing Pluronic^® F127 polymeric micelle system (ICHQ/Mic) was recently shown to be effective against Leishmania amazonensis infection in a murine model. In the present study, ICHQ/Mic was tested against L. infantum infection. BALB/c mice (n = 12 per group) were infected with L. infantum stationary promastigotes through subcutaneous injection and, 45 days after challenge, received saline or were treated via the subcutaneous route with empty micelles, ICHQ or ICHQ/Mic. In addition, animals were treated with miltefosine by the oral route, as a drug control. Half of the animals were euthanized 1 and 15 days after treatment, aiming to evaluate two endpoints after therapy, when parasitological and immunological parameters were investigated. Results showed that the treatment using miltefosine, ICHQ or ICHQ/Mic induced significantly higher anti-parasite IFN-γ, IL-12, GM-CSF, nitrite and IgG2a isotype antibody levels, which were associated with low IL-4 and IL-10 production. In addition, a higher frequency of IFN-γ and TNF-α-producing CD4⁺ and CD8⁺ T-cells was found in these animals. The parasite load was evaluated in distinct organs, and results showed that the treatment using miltefosine, ICHQ or ICHQ/Mic induced significant reductions in organic parasitism in the treated and infected mice. A comparison between the treatments suggested that ICHQ/Mic was the most effective in inducing a highly polarized Th1-type response, as well as reducing the parasite load in significant levels in the treated and infected animals. Data obtained 15 days after treatment suggested maintenance of the immunological and parasitological responses. In conclusion, ICHQ/Mic could be considered in future studies for the treatment of visceral leishmaniasis.

Semisolid Dosage

Already in ancient times, semisolid preparations for cutaneous application, popularly known as ointments, played an important role in human society [...].