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.

Preparation and ex vivo investigation of an injectable microparticulate formulation for gastrointestinal mucosa polyp resection.

Endoscopic submucosal dissection (ESD) and endoscopic submucosal resection (EMR) are non-invasive endoscopic techniques. They allow an early excised gastrointestinal (GI) mucosal precancerous lessions. For their application is necessary to use a submucosal injection that lifts the area to excise. The main objective of this study was the preparation of a microparticulate-based fluid for injection in the GI submucosa. Alginate microparticles (MPs) were developed by the solvent displacement technique and characterized by particle size, surface electrical properties, swelling, degradation, rheology, adhesion, leakage, syringeablity and stability. Furthermore, their potential to form a submucosal cushion was assayed in porcine stomach mucosa and porcine colon mucosa. Results showed MPs sizes below 160 µm, negative surface charge around -50 mV at pH = 6, high rates of swelling and good adhesion. The microparticulate-based fluid exhibited pseudoplastic behavior following the Ostwald-de Waele rheological model. A brief force is sufficient for its injection through a syringe. Finally, formulations were able to provide a submucosa elevation of 1.70 cm for more than 90 min and 120 min in the porcine stomach and colon, respectively.

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.

Biopharmaceutical Study of Triamcinolone Acetonide Semisolid Formulations for Sublingual and Buccal Administration.

The mouth can be affected by important inflammatory processes resulting from localized or systemic diseases such as diabetes, AIDS and leukemia, among others, and are manifested in various types of buccal sores typically presenting pain. This work focuses on the design, formulation, and characterization of four semisolid formulations for oral mucosa in order to symptomatically treat these painful processes. The formulations have two active pharmaceutical ingredients, triamcinolone acetonide (TA) and lidocaine hydrochloride (LIDO). The formula also contains, as an excipient, Orabase®, which is a protective, hydrophobic, and anhydrous adhesive vehicle, used to retain or facilitate the application of active pharmaceutical ingredients to the oral mucosa. After designing the formulations, an analytical method for TA was validated using HPLC so as to achieve reliable analytical results. Franz-type diffusion cells were used to perform drug release studies using synthetic membrane, and permeation studies using buccal mucosa, estimating the amount and rate of TA permeated across the tissue. Additionally, sublingual permeation studies were carried out to evaluate a scenario of a continuous contact of the tongue with the applied formulation. Permeation fluxes and the amount of TA retained within sublingual mucosa were similar to those in buccal mucosa, also implying anti-inflammatory activity in the part of the tongue that is in direct contact with the formulation. In addition, the dynamic conditions of the mouth were recreated in terms of the presence of phosphate buffered saline, constant movement of the tongue, pH, and temperature, using dissolution equipment. The amount of TA released into the phosphate buffered saline in dynamic conditions (subject to being ingested) is well below the normal oral doses of TA, for which the formulation can be considered safe. The formulations applied to buccal or sublingual mucosas under dynamic conditions permit the successful retention of TA within either tissue, where it exerts anti-inflammatory activity. The four formulations studied show a pseudoplastic and thixotropic behavior, ideal for topical application. These results evidence the potential of these topical formulations in the treatment of inflammatory processes in the buccal mucosa.

Novel Polymeric Formulation for Removal of Gastrointestinal Polyps by Digestive Endoscopy.

Endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) are two techniques used in the resection of gastrointestinal mucosal polyps. The aim of this work is the development and evaluation of an innovative polymeric solution containing sodium carboxymethylcellulose and hyaluronic acid. For this purpose, several mixtures of these two main components, as well as other components such as fructose, citric acid, and zinc, are evaluated in terms of physicochemical and microbiological properties, rheological behavior, extensibility, syringeability, and stability at different storage conditions. Furthermore, the potential production of mucosal elevation and duration is also studied by an ex vivo model using porcine stomach and colon. Results show that the developed polymeric solutions possess optimal values of pH, from 4.58 to 6.63, for their use in the gastrointestinal tract. The formulations exhibit both Newtonian and pseudoplastic behaviors with different viscosity values as a function of their composition. All formulations exhibit high stability properties and no bacterial or fungal growth is detected. MCS01 and MCS05 are the polymeric solutions with the best syringeability results. In this line, MCS05 is the formulation that provides the highest, 2.20 ± 0.18 cm and 1.40 ± 0.11 cm, and longest-lasting, for more than 120 min, elevation effect on porcine submucosal stomach and colon tissues, respectively. Thus, it can be concluded that polymeric solution MCS05 might be considered as a promising tool for use in human EMR and ESD.

Design and evaluation of a multifunctional thermosensitive poloxamer-chitosan-hyaluronic acid gel for the treatment of skin burns.

The main goal of this study was the design, development and characterization of a poloxamer/chitosan/hyaluronic based vehicle including three biological antioxidant molecules such as vitamins A, D and E aimed at improving the treatment of skin burns. The physical characterization of hydrogel, its mechanical and rheological properties as well as internal structure were investigated. Furthermore, biological characteristics such as ex vivo antimicrobial properties and in vivo wound healing were also accomplished and compared with a commercial reference. Results showed optimal physicochemical properties with biocompatible pH value of 4.6 ±â€¯0.1 and zeta potential dependent on pH. The swelling rate was around 350% with optimal wettability, adhesion and leakage properties, as well as thermosensitive gelation processes. The microbiological assay demonstrated similar antimicrobial activity to that of commercial reference. In vivo tolerance study revealed no skin reactions. Finally, the wound healing efficacy of hydrogel in skin burn model showed dermal appendages and similar epidermis, dermis and stratum corneum to the commercial reference. These findings indicated that our hydrogel loading vitamins could be considered an outstanding candidate for further clinical studies.

Design and evaluation of mesenchymal stem cells seeded chitosan/glycosaminoglycans quaternary hydrogel scaffolds for wound healing applications.

The main goal of this study was the design, development and characterization of a chitosan based scaffolding substrate including three glycosaminoglycans and collagen to provide an optimal microenvironment for human mesemchymal stem cells isolated from adipose tissue (hMSCs). Chitosan scaffolds provide a moist wound environment which promotes healing and epidermal regeneration. Furthermore, the importance of extracellular molecules such as glycosaminoglycans in wound healing makes them essential ingredients in these types of formulations. The physical properties of hydrogels scaffolds and stability were investigated. The scaffolds were evaluated by structural and microscopic assays, as well as cell culture analyses. The hydrogel with best suitable properties was selected as candidate scaffold for hMSCs encapsulation. The viability of hMSCs remained above 75%, indicating good cell viability. The number of living hMSCs in the scaffold reached a steady state up to ~100% at days 5 and 7. Scanning electron microscopy showed irregular compartments with the presence of the hMSCs. These findings indicated that our hydrogel scaffold provided a suitable niche for cell viability which could be considered a promising candidate for further in vivo studies.

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.

Developing cutaneous applications of paromomycin entrapped in stimuli-sensitive block copolymer nanogel dispersions.

AIM: A new paromomycin micellar nanogel based on poloxamer 407 was developed. MATERIALS & METHODS:  In vitro release and ex vivo permeation/retention studies were conducted. In vivo tolerance was assayed by transepidermal water loss. Ex vivo cytotoxicity on RAW and VERO cells and antileishmanial activity on Leishmania promastigotes was tested. RESULTS: The particle size was 9.19 nm (99% loading efficiency) exhibiting Newtonian behavior at 4°C and was pseudoplastic at 25 and 40°C. Drug release followed a Weibull model and the drug remaining in the skin was 31.652 µg/g/cm(2). In vivo tolerance achieved excellent results with negligible cellular toxicity and the best antileishmanial efficiency. CONCLUSION: The nanogel provided controlled, effective and safe delivery of paromomycin for the treatment of cutaneous leishmaniasis.

Study of the stability of packaging and storage conditions of human mesenchymal stem cell for intra-arterial clinical application in patient with critical limb ischemia.

Critical limb ischemia (CLI) is associated with significant morbidity and mortality. In this study, we developed and characterized an intra-arterial cell suspension containing human mesenchymal stem cells (hMSCs) for the treatment of CLI. Equally, the stability of cells was studied in order to evaluate the optimal conditions of storage that guarantee the viability from cell processing to the administration phase. Effects of various factors, including excipients, storage temperature and time were evaluated to analyze the survival of hMSCs in the finished medicinal product. The viability of hMSCs in different packaging media was studied for 60 h at 4 °C. The best medium to maintain hMSCs viability was then selected to test storage conditions (4, 8, 25 and 37 °C; 60 h). The results showed that at 4 °C the viability was maintained above 80% for 48 h, at 8 °C decreased slightly, whereas at room temperature and 37 °C decreased drastically. Its biocompatibility was assessed by cell morphology and cell viability assays. During stability study, the stored cells did not show any change in their phenotypic or genotypic characteristics and physicochemical properties remained constant, the ability to differentiate into adipocytes and osteocytes and sterility requirements were also unaltered. Finally, our paper proposes a packing media composed of albumin 20%, glucose 5% and Ringer's lactate at a concentration of 1×10(6) cells/mL, which must be stored at 4 °C as the most suitable to maintain cell viability (>80%) and without altering their characteristics for more than 48 h.

Formulation design and optimization for the improvement of nystatin-loaded lipid intravenous emulsion.

Nystatin (NYS) is a polyene macrolide with broad antifungal spectrum restricted to topical use owing to its toxicity upon systemic administration. The aims of this work were the design, development, and optimization of NYS-loaded lipid emulsion for intravenous administration. A closed circuit system was designed to apply ultrasound during the elaboration of the lipid intravenous emulsions (LIEs). Additionally, a comparison with the commercially available Intralipid(®) 20% was also performed. Manufacturing conditions were optimized by factorial design. Formulations were evaluated in terms of physicochemical parameters, stability, release profile, and antimicrobial activity. The average droplet size, polydispersity index, zeta-potential, pH, and volume distribution values ranged between 192.5 and 143.0 nm, 0.170 and 0.135, -46 and -44 mV, 7.11 and 7.53, 580 and 670 nm, respectively. The selected NYS-loaded LIE (NYS-LIE54) consisted of soybean oil (30%), soybean lecithin (2%), solutol HS(®) 15 (4%), and glycerol (2.25%) was stable for at least 60 days. In vitro drug release studies of this formulation suggested a sustained-release profile. Equally, NYS-LIE54 showed the best antimicrobial activity being higher than the free drug. Thus, it could be a promising drug delivery system to treat systemic fungal infections.

Validated spectrofluorometric method for determination of gemfibrozil in self nanoemulsifying drug delivery systems (SNEDDS).

A spectrofluorometric method has been developed and validated for the determination of gemfibrozil. The method is based on the excitation and emission capacities of gemfibrozil with excitation and emission wavelengths of 276 and 304 nm respectively. This method allows de determination of the drug in a self-nanoemulsifying drug delivery system (SNEDDS) for improve its intestinal absorption. Results obtained showed linear relationships with good correlation coefficients (r(2)>0.999) and low limits of detection and quantification (LOD of 0.075 µg mL(-1) and LOQ of 0.226 µg mL(-1)) in the range of 0.2-5 µg mL(-1), equally this method showed a good robustness and stability. Thus the amounts of gemfibrozil released from SNEDDS contained in gastro resistant hard gelatine capsules were analysed, and release studies could be performed satisfactorily.

Development and characterization of a novel nystatin-loaded nanoemulsion for the buccal treatment of candidosis: ultrastructural effects and release studies.

Oral candidosis is a common opportunistic infection in patients suffering from mucositis (after chemotherapy and radiotherapy administration) and must be treated to prevent infecting other tissue. Nystatin (Nys) is one of the most prescribed drugs to treat this pathology, but because of its physicochemical properties, its pharmaceutical-technological requirements make it a challenge. The purpose of this work was the development and characterization of an optimal Nys delivery system for the potential treatment of oral candidosis avoiding undesirable side effects and toxicity of potential systemic absorption. A nanoemulsion was developed, evaluated, and characterized. It has been formulated successfully as a stable nanoemulsion with a droplet size of 138 nm. Release parameters were estimated using different mathematical approaches, and from the results of ex vivo permeation study of Nys through porcine buccal mucosa, it could be hypothesized that no systemic effects would happen. Microbiologic studies performed revealed an enhanced antifungal effect of the Nys-loaded nanoemulsion. Also, the evaluation of the treated buccal mucosa ultrastructure by transmission electron microscopy revealed a harmless effect. Thus, it could be inferred that the developed formulation could be potentially utilized for candidosis infection under mucositis conditions.