Formulation and optimization of alginate-methotrexate microspheres produced by emulsification technique
PREPARATION AND EVALUATION OF ALGINATE-METHOTREXATE MICROSPHERES S, Hashem Monta Shohre Alipour Saba afifi,
Department of Pharmaceutics, Faculty of Pharmacy, Shiraz University of Medical
Sciences, P.O. Box 71345-1583, Shiraz, Iran
Introduction: Recently, much research has been focused on degradable polymer microspheres for drug delivery. Administration of chemotherapeutic agents such as methotrexate via such systems is advantageous. Because microspheres can be ingested or injected; they can be tailored for desired release profiles and in some cases even provide organ-targeted release. So lower dosed and less frequent injections as a result of localized therapy and controlled release make a microspheres drug delivery system a good candidate for cancer therapy. Among the wide spectrum of polymers, alginate is so popular because of its safety, biocompatibility, biodegradability and non-immunogenicity. Experimental Method: In this study we have used emulsification- internal gelation method. The alginate microspheres were produced by cross-linking alginate globules dispersed in a continuous organic phase using various concentrations of calcium chloride solution. Different parameters in formulation have been studied such as alginate type (low viscosity & medium viscosity) and concentration (1-5%), calcium concentration (0.25-3.5%), surfactant concentration (1-3%) and curing time. Microspheres’ size was determined by laser diffraction particle size analyzer. The size of microspheres and amount of drug loaded was the comparison factor for different formulations. The encapsulation efficiency was determined by HPLC method. Results and Discussion: The formulation containing a mixture of 0.5%HPMC and 4.5% alginate cured in 0.75% calcium chloride for 20 minutes was chosen as the best formula regarding the particle size and the loading efficiency. The resulting microspheres had a volume mean diameter of 6 µm and loading efficiency of about 20%. Key words: methotrexate, alginates, Microspheres References: [1] Anamika Roy, J. Bajpai, A.K. Bajpai ,Carbohydrate Polymers, In Press. [2] Chaoyang Wang, Hongxia Liu, Quanxing Gao, Xinxing Liu, Zhen Tong, Carbohydrate Polymers, Volume 71, Issue 3, 8 February 2008, Pages 476-480.
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[3] Susana Martins, Bruno Sarmento, Eliana B. Souto, Domingos C. Ferreira , Carbohydrate Polymers, Volume 69, Issue 4, 2 July 2007, Pages 725-731. [4] R. Rastogi, Y. Sultana, M. Aqil, A. Ali, S. Kumar, K. Chuttani, A.K. Mishra, International Journal of Pharmaceutics, Volume 334, Issues 1-2, 4 April 2007, Pages 71-77.Biomaterials, Volume 28, Issue 20, July 2007, Pages 3140-3152 [6] A. Lebugle, A. Rodrigues, P. Bonnevialle, J. J. Voigt, P. Canal, F. Rodriguez, Biomaterials,
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Lung Transplantation: A Decade of Experience Susan D. Moffatt, MD, PhD,a Philippe Demers, MD,a Robert C. Robbins, MD,a Ramona Doyle, MD,bAnn Wienacker, MD,b Noreen Henig, MD,b James Theodore, MD,b Bruce A. Reitz, MD,a andRichard I. Whyte, MDa Background: Over the past 3 decades, the field of lung transplantation has been refined. However, many barriersexist that limit long-term success. The
GBS (Group B Streptococcus) First, you should know that Group B Strep is a bacterium that lives in the intestines and reproductive areas of about a third of the healthy population. It is normally not something to think about. The reason the subject comes up in pregnancy is that GBS is more dangerous to certain groups of people, including infants, than to the general population. When Mom car