Elzíria de Aguiar Nunan

In Vitro Skin Permeation and Retention of Paromomycin from Liposomes for Topical Treatment of the Cutaneous Leishmaniasis

Paromomycin (PA), a very hydrophilic antibiotic, has been tested as an alternative topical treatment against cutaneous leishmaniasis (CL). Although this treatment has shown promising results, it has not been successful in accelerating the recovery in most cases. This could be attributed to the low skin penetration of PA. Liposomal formulations usually provide sustained and enhanced drug levels in skin. The aim of this study was to prepare liposomal formulations containing PA and to investigate their potential as topical delivery systems of this antileishmanial. Large multilamellar vesicles (MLVs) were prepared by conventional solvent evaporation method. Large unilamellar vesicles (LUVs) were prepared by reverse‐phase evaporation method. The lipids used were soybean phosphatidylcholine (PC) and PC:cholesterol (CH) (molar ratio 1:1). The skin permeation experiments across stripped and normal hairless mice skin were performed in modified Franz diffusion cells. The PA entrapment in LUV liposomes (20.4 ± 2.2%) was higher than that observed for MLV liposomes (7.5 ± 0.9%). Drug entrapment was 41.9 ± 6.2% and 27.2 ± 2.4% for PC and PC:CH LUV, respectively. The skin permeation was 1.55 ± 0.31%, 1.29 ± 0.40%, 0.20 ± 0.08%, and 0.50 ± 0.19% for PC LUV, PC:CH LUV, empty LUV + PA and aqueous solution, respectively. Controlled topical delivery, across stripped skin, was observed for PA entrapped in LUV liposomes.

Effect of age on body distribution of Tityustoxin from Tityus serrulatus scorpion venom in rats.

Previous research from our Laboratory has shown a greater susceptibility of young animals, when compared to adults, to envenomation by tityustoxin (TsTX), one of the main toxins from Tityus serrulatus scorpion venom. Our hypothesis is that a differential body distribution of TsTX among adult and young animals could account for the worse prognosis of scorpion envenomation in infants. Thus, TsTX labeled with technetium-99m was injected (6 microg, subcutaneous) in adult (150-160 day-old) and young (21-22 day-old) male rats. Groups of animals were sacrificed at different times after TsTX injection (0.08, 1.0, 3.0, 6.0, 12.0 and 24.0 hours) under Urethane anesthesia (140 mg/100 g, i.p.). The brain, heart, lungs, liver, kidneys, spleen and thyroid were excised and blood collected. Young rats presented a shorter latency toxin concentration peak in all studied organs except for the liver and the kidney, when compared to adults. The ratio between the area under the curve of the toxin concentration in each organ and that in blood (Kp) indicates higher accumulation in the organs of young animals mainly for brain, liver and heart. These observations suggest a faster toxin distribution in the organs of young rats. The higher uptake of TsTX in the brain is suggestive of a greater permeability for the toxin along the blood-brain barrier of young rats. In conclusion, the higher uptake in heart, together with data from the brain, may help to elucidate the clinical manifestations frequently observed in children under scorpion envenomation.

Topical delivery and in vivo antileishmanial activity of paromomycin-loaded liposomes for treatment of cutaneous leishmaniasis

The present study aimed to evaluate the potential of liposomes loaded with paromomycin (PA), an aminoglycoside antibiotic associated with poor skin penetration, for the topical treatment of cutaneous leishmaniasis (CL). Fluid liposomes were prepared and characterized for particle size, zeta potential, and drug entrapment. Permeation studies were performed with two in vitro models: intact and stripped skin. The antileishmanial activity of free and liposomal PA was evaluated in BALB/c mice infected by Leishmania (L.) major. Drug entrapment ranged from 10 to 14%, and the type of vesicle had little influence on this parameter. Particle size and polydispersity index of the vesicles composed by phosphatidylcholine (PC) and PC/cholesterol (Chol) ranged from of 516 to 362 nm and 0.7 to 0.4, respectively. PA permeation across intact skin was low, regardless of the formulation tested, while drug penetration into skin (percent of the applied dose) from PC (7.2 ± 0.2%) and PC/Chol (4.8 ± 0.2%) liposomes was higher than solution (1.9 ± 0.1%). PA-loaded liposomes enhanced in vitro drug permeation across stripped skin and improved the in vivo antileishmanial activity in experimentally infected mice. Our findings suggest that the liposomes represent a promising alternative for the topical treatment of CL using PA.

Combined topical paromomycin and oral miltefosine treatment of mice experimentally infected with Leishmania (Leishmania) major leads to reduction in both lesion size and systemic parasite burdens

OBJECTIVES This study aimed to investigate the activity of the combination of topical paromomycin gel and oral miltefosine for the treatment of experimental cutaneous leishmaniasis caused by Leishmania (Leishmania) major. METHODS The efficacy of the combination, evaluated by measuring lesion size and parasite burden in the skin and spleen, was assessed in BALB/c mice infected by L. (L.) major. Miltefosine was administered orally at 25 mg/kg/day for 10 days, while 10% paromomycin gel was applied topically twice a day for 10 days. RESULTS Treatment of the experimentally infected animals with topical paromomycin + oral miltefosine combination induced a statistically significant reduction in lesion size and parasite burden in the skin, with complete healing of ulcers, as compared with those treated with oral miltefosine or placebo. Furthermore, topical paromomycin + oral miltefosine combination was as effective as topical paromomycin alone to reduce the lesion size and parasite load in lesions. However, the efficacy of the combination was significantly higher than that observed for the other treatments, including topical paromomycin alone, in reducing the parasite burden in spleen. CONCLUSIONS The combination of topical paromomycin gel and oral miltefosine provides an enhanced efficacy in the treatment of L. (L.) major-infected mice, thus presenting a significantly higher activity than that observed for the monotherapeutic regimens.

Determinação de daidzeína, genisteína e gliciteína em cápsulas de isoflavonas por cromatografia em camada delgada (CCD) e cromatografia líquida de alta eficiência (CLAE)

The use of herbal products and supplements based on isoflavone dry extracts has increased considerably in the last decade, mainly due to beneficial effects to relief of the menopausal symptoms credited to those compounds. Genistein, daidzein and glycitein are the most abundant isoflavone aglycones found in soy extract, where they also occur as glycosides. Concerning their uses, there is neither standardization regarding the minimum content of each aglycone in the extracts or capsules, nor an official method to the quality control of these products. The present work presents a TLC method for qualitative analysis of the three aglycones and their glycosides in extracts and capsules of isoflavones, before and after acid hydrolysis. The quantitative analysis of the isoflavone capsules, carried out by high performance liquid chromatography (HPLC), showed high variation in the content of the three aglycones, after acid hydrolysis. The contents varied in the following way, in the 18 batches of evaluated capsules: daidzein (13.34 to 76.20 mg/capsule), genistein (0.61 to 27.18 mg/capsule) and glycitein (0.49 to 8.80 mg/capsule).

Chromatographic evaluation and antimicrobial activity of Neem (Azadirachta indica A. Juss., Meliaceae) leaves hydroalcoholic extracts

Neem (Azadirachta indica) is an Indian tree well known for its several pharmacological activities, including antimicrobial activity. More than 300 composites have already been isolated and azadirachtin (AZA) is its main active component. In the present work, Neem leaves hydroalcoholic extracts were prepared by percolation in 96% ethanol different concentrations (50%, 60%, 70%, 80% and 90% (v/v)). The presence of AZA was tested by TLC by eluting the extracts and a standard solution of AZA through a chromatographic plate developed with anisaldehyde/sulfuric acid solution followed by heating. By HPLC, extracts elution took place on a C18 column, water:acetonitrile (60:40) as mobile phase, 1.0 mL/min flow rate and detection at λ217 nm. The extracts did not display AZA spots or peaks, however, they were tested against Gram-positive and Gram-negative bacteria, yeasts and a mold fungus. The extracts were tested in different increasing concentrations, in order to detect a dose-dependent relationship of the activity. Despite the absence of AZA, the 70% and 80% (v/v) ethanol extracts showed activity against Staphylococcus aureus. However, this activity was not dose-dependent according to Tukeys test (q0,05;3;7).

Technetium-99m labeling of tityustoxin and venom from the scorpion Tityus serrulatus

The tityustoxin, the most toxic fraction from scorpion Tityus serrulatus venom, has been used as a tool in several neurochemical and neuropharmacological studies. Biological activities of labeled and unlabeled tityustoxin and venom were compared. The samples were labeled in the presence of stannous chloride and sodium borohydride with a yield of 60-70% for the venom and 75-85% for tityustoxin and then chromatographed in Sephadex G-10. Biological activities of tityustoxin and venom were preserved after labeling.

Atividade antimicrobiana in vitro do rizoma em pó, dos pigmentos curcuminóides e dos óleos e dos essenciais da Curcuma longa L.

Este trabalho teve como objetivo avaliar a atividade antimicrobiana da curcuma em po, da curcumina disponivel no comercio, dos pigmentos curcuminoides purificados e dos oleos essenciais da curcuma. As amostras foram analisadas quanto aos teores de pigmentos curcuminoides por cromatografia liquida de alta eficiencia. O oleo essencial foi tambem analisado quanto a densidade, indice de refracao e perfil das substâncias volateis por cromatografia gasosa e detector de ionizacao de chamas. A atividade antimicrobiana in vitro foi determinada pelo metodo de difusao em agar com discos de papel estereis, impregnados com os extratos, sendo os diâmetros dos halos de inibicao medidos com paquimetro. Os extratos etanolicos da curcuma, da curcumina comercial, e dos pigmentos curcumina e desmetoxicurcumina nao inibiram o crescimento de Staphylococcus aureus, Bacillus subtilis, Salmonella choleraesuis, Escherichia coli, Aspergillus niger, Saccharomyces cerevisiae, e Candida albicans. Apenas o extrato etanolico da bisdesmetoxicurcumina apresentou atividade antimicrobiana em relacao ao B. subtilis. O oleo essencial da curcuma apresentou atividade antimicrobiana para o B. subtilis, S. choleraesuis, E. coli, A. niger e S. cerevisiae, sendo que essa atividade aumentou em funcao do aumento da concentracao. Os halos de inibicao, obtidos com o oleo essencial, foram significativos, quando comparados aos respectivos antibioticos tradicionais, cloranfenicol e anfotericina, indicando ser o oleo essencial da curcuma um agente antimicrobiano em potencial.

The Influence of Formulation on the Dissolution Profile of Diclofenac Sodium Tablets

ABSTRACT In attempts to design delayed-release tablets of diclofenac sodium, seven experimental batches were produced. The influence of super-disintegrant croscarmellose sodium (CCS), the granulation process, and the thickness of Eudragit® L 100 coating film were evaluated. The values of dissolution efficiency and the similarity factor were used to compare the dissolution profiles of each experimental batch and the reference Voltaren®. Both methods appear to be applicable and useful in comparing dissolution profiles. Based on such values four batches were considered similar when contrasted with the reference. The results suggest an optimal relationship between the amount of CCS and the thickness of the coating film, which provides appropriate dissolution rate of diclofenac sodium from the dosage forms.

Quantitation of genistein and genistin in soy dry extracts by UV-Visible spectrophotometric method

This paper describes the development and validation of an UV-Visible spectrophotometric method for quantitation of genistein and genistin in soy dry extracts, after reaction with aluminum chloride. The method showed to be linear (r2= 0.9999), precise (R.S.D. < 2%), accurate (recovery of 101.56%) and robust. Seven samples of soy dry extracts were analyzed by the spectrophotometric validated method and by RP-HPLC. Genistein concentrations determined by spectrophotometry (0.63% - 16.05%) were slightly higher than values obtained by HPLC analysis (0.40% - 12.79%); however, the results of both methods showed a strong correlation.