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Development of a transdermal patch for delivery of propafenone: preliminary studies in vitro
No full textPropafenone, a well-known antiarrhythmic drug, has a low oral bioavailability due to extensive hepatic first-pass metabolism The present study was aimed at verifying, on a preliminary basis, feasibility of transdermal delivery of the drug. Propafenone is apparently unable to penetrate the skin in the absence of appropriate enhancers. Different prospective enhancers (terpenes, azone) for the drug hydrochloride and base were evaluated in vitro using hairless mouse skin. Propafenone hydrochloride and atone, the most favourable drug species and enhancer combination, were then incorporated into semisolid vehicles, designed to act as reservoirs in transdermal patches. The patches, with and without a microporous membrane and adhesive layer were then tested for transdermal release using the same in vitro model. Skin, not membrane permeation, was found to be the rate-limiting step in delivery from the final patches. These, after 5 to 6 h lag times, delivered propafenone hydrochloride at a constant rate (5.4 to 27.5 mu g/cm(2)/h) for over 48 h. Since the literature data on intravenous infusion of propafenone appear to indicate the need for higher rates, further research on more effective promoters and transdermal patches is in progres
Los trilobites y el Paleozoico temprano
Full text linkUna visita a la historia de los trilobites, extinguidos pobladores de los mares paleozoicos cuyo estudio arroja luz sobre una amplia gama de cuestiones investigadas por geólogos y paleontólogos.Fil: Tortello, Marcelo Franco. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Departamento Científico Zoología Vertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Monti, Daniela Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Ecología, Genética y Evolución de Buenos Aires. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Ecología, Genética y Evolución de Buenos Aires; Argentin
Ophthalmic emulsions and suspensions (Reprinted from Pharmaceutical Emulsions and Suspensions, pg 303-322, 2000)
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Ciclopirox: recent nonclinical and clinical data relevant to its use as a topical antimycotic agent
No full textCiclopirox is a topical antimycotic agent belonging to the chemical class of hydroxypyridones and not related to azoles or any other class of antifungal agents. Its antimicrobial profile includes nearly all of the clinically relevant dermatophytes, yeasts and moulds, and is therefore broader than that of most other antimycotics. It is also active against certain frequently azole-resistant Candida species and against some bacteria.
The mechanism of action of ciclopirox is different from that of other topical antifungal drugs, which generally act through ergosterol inhibition. The high affinity of ciclopirox for trivalent metal cations, resulting in inhibition of the metal-dependent enzymes that are responsible for the degradation
of peroxides within the fungal cell, appears to be the major determinant of its antimicrobial activity. This unique and multilevel mechanism of action provides a very low potential for the development of resistance in pathogenic fungi, with cases of resistance rarely reported.
Ciclopirox also displays mild anti-inflammatory effects in biochemical and pharmacological models; effects also shown in small clinical studies.
Scavenging of reactive oxygen species released from inflammatory cells is a likely contributor to these anti-inflammatory effects.
Ciclopirox, and its olamine salt, is available in multiple topical formulations, suitable for administration onto the skin and nails and into the vagina.
The pharmaceutical forms most widely investigated are 1% ciclopirox olamine cream and 8% ciclopirox acid nail lacquer, but lotion, spray, shampoo, pessary, solution, gel and douche formulations have also been used. Ciclopirox penetrates into the deep layers of the skin, mucosal membranes and nail keratin, reaching concentrations exceeding the minimal fungicidal concentrations for most medically important fungi.
A large number of clinical trials were and are still being performed with ciclopirox, starting in the early 1980s. Ciclopirox was first developed for fungal skin infections and vaginal candidiasis, and is currently well established
in these indications. More recently, the drug has been clinically investigated in seborrhoeic dermatitis and onychomycosis, showing good efficacy and excellent tolerability. Emphasis in this review is given to a ciclopirox medicated nail lacquer, which is based on an original technology and has superior properties in terms of its affinity to keratin and nail permeation. It has been found to have superior efficacy and safety to another commercially available formulation in the treatment of onychomycosis.
The safety features of ciclopirox are well known. The topical drug is devoid of systemic adverse reactions. Mild local reactions characterized by a burning sensation of the skin, irritation, redness, pain or pruritus, generally in less than 5% of treated patients, can be observed following skin and vaginal
application. With nail application, the most common adverse event is the appearance of mild erythema in 5% of the treated population.
As a general conclusion, although less effective than some oral antimycotic agents in various indications, ciclopirox compares very well in terms of the benefit/risk ratio due to its excellent tolerability and complete absence of serious adverse effects
Liposome-encapsulated motomycin C for reduction of corneal healing rate and ocular toxicity
No full textMitomycin-C (MMC), a potent antibiotic-antineoplastic drug, has recently proven to be useful as additional treatment in ocular surgery (pterygium, glaucoma filtering, photorefractive laser keratectomy, etc.) when inhibiting the epithelial wound healing response and reducing surgical scarring is beneficial to surgical success. However, the therapeutic benefits of MMC are frequently offset by ocular toxicity and undesirable side effects (retinal toxicity, corneal edema, corneal perforation, cataract, secondary glaucoma, iritis, scleral calcification, pain, etc.). The purpose of this study was to evaluate if a liposomal preparation containing MMC was capable of reducing the corneal healing rate and drug toxicity of a corneal lesion in a rabbit model. To do this, a liposomal formulation containing 0.2 mg/ml of MMC was prepared and tested against aqueous solutions and viscous formulations based on tamarind seeds polysaccharide (TSP), which were used as references. In vitro release of MMC from the vehicles through a dialysis membrane was characterized by a fast diffusion of MMC from the aqueous solution, while a more gradual release from the TSP and the liposomal formulations was observed. To evaluate the intraocular penetration of MMC, the drug amount in the aqueous and vitreous humor of the animals was determined 60 min after treatment. MMC toxicity was analyzed by monitoring the proliferation and viability of a rabbit corneal epithelial cell line (RCE) in the different formulations under study. These results showed reduced cytotoxicity for MMC in TSP viscous vehicles; however, only the liposomal MMC vehicle appeared to produce both lower toxicity for a rabbit corneal epithelial cell line (RCE) culture and a substantial reduction of the corneal healing rate in vivo
Ophthalmic composition containing mucoadhesive polysaccharides stimulating corneal epithelium recovery
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