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El-Ridy M.S.,National Research Center of Egypt | Abdelbary A.,Cairo University | Nasr E.A.,Veterinary Serum and Vaccine Research Institute VSVRI | Khalil R.M.,National Research Center of Egypt | And 3 more authors.
Drug Development and Industrial Pharmacy | Year: 2011

It is estimated that more than one-third of the world population is infected with Mycobacterium tuberculosis. Pyrazinamide (PZA) plays a unique role in shortening therapy because it kills a population of semilatent tubercle bacilli residing in an acidic environment. Niosomes are vesicles made up of non-ionic surfactant and exhibit behavior similar to liposomes in vivo. Preparation of PZA niosomes took place using different molar ratios of Span 60 and Span 85, with cholesterol (CH) i.e. Span: CH (1:1) and (4:2). Dicetyl phosphate and stearyl amine were used in preparation of negative and positively charged niosomes, respectively. Free PZA was separated by cooling centrifugation and estimated spectrophotometrically at 268.4 nm. Niosomes were characterized by electron microscopy and differential scanning calorimetry. The highest percentage PZA entrapped was obtained using Span 60 and the molar ratio (4:2:1) negatively charged niosomes. This was followed by the neutral PZA neutral (4:2) Span 60 niosomes. Biological evaluation of selected PZA niosomal formulations took place on guinea pigs infected with M. tuberculosis. The present work is an attempt to target maximum concentration of PZA to the affected site (lungs) and to exclude undesirable side effects and decrease toxicity. Macrophage targeting and overcoming drug resistance is our final goal. © 2011 Informa Healthcare USA, Inc.

Ghazy N.A.,Veterinary Serum and Vaccine Research Institute VSVRI | Abdel Aziz W.R.,Veterinary Serum and Vaccine Research Institute VSVRI | Shell W.S.,Biologics | Samy A.A.,National Research Center of Egypt
Asian Journal of Animal and Veterinary Advances | Year: 2016

Background: Brucellosis is an important zoonotic bacterial disease of global health importance affecting different animals and man. Brucellosis control and eradication procedures are highly depending on accurate diagnostic tools and effective and safe vaccination programs. Rapid slide agglutination tests using different antigens as rose bengal antigen and Buffered Acidified Plate Antigen (BAPA) are considered as cheap, quick and effective tests for diagnosis and screening of brucellosis. Materials and Methods: With respect to packed cells volume and pH, specificity and sensitivity of 18 different slide agglutination antigens (rose bengal and buffered acidified plate agglutination antigens) prepared in Veterinary Serum and Vaccine Research Institute were evaluated. In the absence of bacteriological isolation, complement fixation test was used as a Gold Standard test. Results: No satisfactory differences with the results of rapid slide agglutination antigens with different pH and this may be due to narrow range of pH used in this study. However, when antigens of different packed cells volume were used, a high degree of sensitivity appeared especially when buffered acidified plate agglutination and modified rose bengal tests were carried out using antigens of cell concentration of 4 and 6%. In contrast specificity was decreased with antigens of less packed cells volume. Modified rose bengal and buffered acidified plate agglutination tests using antigens with cell concentration 4 and 6% showed lowest specificity. Conclusion: Results revealed that modified rose bengal and Buffered Acidified Plate Agglutination (BAPA) tests using antigens with lower cells concentrations than that of international standard are recommended to be used especially in animals of low anti-brucella titers and endemic areas with brucellosis especially when Brucella melitensis is the main causative agent. Modified rose bengal test and BABA test using antigens of cell concentration of 4-6% is recommended for diagnosis of B. melitensis infection. © 2016 Nabila A. Ghazy et al.

El-Ridy M.S.,National Research Center of Egypt | Yehia S.A.,Cairo University | Kassem M.A.-E.-M.,National Research Center of Egypt | Mostafa D.M.,National Research Center of Egypt | And 2 more authors.
Drug Delivery | Year: 2015

Context: Tuberculosis (TB) is a worldwide health concern. In 2011, about 8.7 million new cases developed TB and 1.4 million people died from it.Objective: Enhancement of ethambutol hydrochloride activity and safety in treatment of TB through niosomal encapsulation.Materials and methods: Niosomes were prepared by the thin-film hydration method. They were characterized, investigated for in vitro release, lung disposition and in vivo biological evaluation.Results: Entrapment efficiency of ethambutol hydrochloride ranged from 12.20% to 25.81%. Zeta potential values inferred stability of neutral and negatively charged formulations. In vitro release was biphasic. Lung targeting was increased by niosomal encapsulation. Biological evaluation revealed superiority of niosomal ethambutol hydrochloride over the free drug.Discussion: Neutral and negatively charged niosomal vesicles are dispersed homogenously unlike positively charged vesicles. Niosomal encapsulation results in controlled drug release. Niosomal formulations targeted more drugs to mice lungs for a prolonged period of time resulting in: decreased root-specific lung weight, bacterial counts in lung homogenates and optimizing pathological effect on guinea pigs lungs, livers and spleens.Conclusion: Encapsulation of ethambutol hydrochloride in niosomal formulations for the treatment of TB provides higher efficacy and safety compared with the free drug. © 2013 Informa Healthcare USA, Inc. All rights reserved.

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