The determination of some toxic elements in drinking water by inductively coupled plasma mass spectrometry

A method is described for the determination of Cu, Cr, Cd, Pb, Sb, Se and As in drinking water using inductively coupled plasma mass spectrometry (ICP-MS). Samples were taken from water treatment plants of Negeri Sembilan and Melaka. Modified methods were developed for the trace determination of total inorganic arsenic, antimony, chromium, cadmium, selenium, lead, copper and mercury by ICP-MS. Detection limits obtained by ICP-MS for Cr, Cu, As, Se, Cd, Sb and Pb are 250, 66, 59, 48, 8, 85 and 3.28 103 g L-1 respectively. Calibration was accomplished by means of an aqueous calibration curve. The methods were verified by the analysis of quality control standard sample solutions

Effect of process variables on the preparation of BSA loaded double-walled poly(lactide-co-glycolide) microspheres

Biodegradable poly(lactide-co-glycolide) (PLGA) microspheres have received much attention over the last twenty-five years for controlled parenteral delivery of therapeutic protein and peptide drugs [1, 2]. In general, for protein drugs delivery, PLGA and PLGA-based single-polymer microspheres system still suffer from two major technical problems associated with their inherent stability problem [3]. Initial burst release followed by very slow and incomplete release is one of the most serious problems in the formulation of PLGA-based protein drugs delivery system. Many strategies have been explored currently to reduce the high initial burst release of protein and peptide drugs from PLGA microspheres [4]. Fabrication of double-walled microspheres in which protein drugs encapsulated in the inner core surrounded by a drug free outer polymer layer offers a promising technique in reducing the high initial burst release. In previous studies, large size double-walled microspheres have been prepared using poly(L-lactic acid) (PLLA) and different co-polymers of PLGA (ester-terminated and carboxyl-terminated) as the core and shell material. Double-walled microspheres consisting PLLA and ester-terminated PLGA as the core or shell material required more time for the complete release of encapsulated drugs due to the slow degrading nature of these polymers