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AOAC Final Action Official MethodSM 2015.06 "Minerals and Trace Elements in Milk, Milk Products, Infant Formula and Adult/Pediatric Nutritional Formula, ICP-MS Method" was collaboratively studied. Note that "milk, milk products" has now been added to the title of the Final Action method because whole milk and several dairy ingredients were successfully incorporated into the collaborative study for the purpose of developing an International Organization for Standardization/International Dairy Federation standard (ISO/DIS 21424; in progress). The method determines sodium, magnesium, phosphorus, potassium, calcium, iron, manganese, zinc, copper, chromium, molybdenum, and selenium by inductively coupled plasma (ICP)-MS after microwave digestion. Ten laboratories participated in the study, and data from five different model ICP-MS units were represented. Thirteen products, five placebo products, and six dairy samples were tested as blind duplicates in this study, along with a standard reference material, for a total 50 samples. The overall repeatability and reproducibility for all samples met Standard Method Performance Requirements put forth by the AOAC Stakeholder Panel on Infant Formula and Adult Nutritionals, with a few exceptions. Comparisons are made to ICP-atomic emission data from a collaborative study of AOAC Official Method 2011.14 carried out concurrently on these same samples.

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Objective: A novel, sensitive and accurate high-performance liquid chromatography with ultraviolet/visible light detection (HPLC-UV/VIS) method for the quantification of ledipasvir and Sofosbuvir in plasma was developed and validated. Methods: The analytes were extracted by liquid-liquid extraction method and chromatograph using a mobile phase consisting of acetonitrile and buffer solution, Methanol and Acetonitrile in the ratio of 200:600:200 (v/v) using Oyster BDS RP-C18 column. The flow rate 1.0 ml/min and UV detection at 238 nm were employed. The retention time for Ledipasvir and Sofosbuvir was 4.61 and 9.09 min respectively. Linearity for ledipasvir and Sofosbuvir was found to be in the range of 250-2000 ng/ml for both drugs respectively. Intra-and inter-day precision was less than 2% coefficient of variation.Results: The method was validated as per the USFDA guidelines and the results were within the acceptance criteria for selectivity, sensitivity, linearity, precision, accuracy, recovery stability of the solution, the stability of solution in plasma and dilution integrity.Conclusion: Majority of the HPLC method should be useful for monitoring human plasma drug concentrations, and pharmacokinetic studies in patients diagnosed with the Ledipasvir and Sofosbuvir formulations.

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