LC-UV method to assay raloxifene hydrochloride in rat plasma and its application to a pharmacokinetic study

A specific, precise, and accurate LC-UV method was developed and validated to assay raloxifene hydrochloride in rat plasma. Raloxifene was analyzed after liquid-liquid extraction and quantified by reversed phase liquid chromatography (C18 column) using acetonitrile and ammonium acetate buffer 0.05 M (pH 4.0) as mobile phase at a flow rate of 1 mL.min-1 and UV detection at 287 nm. Retention times of raloxifene and internal standard (dexamethasone) were approximately 11 min and 14 min, respectively. Linearity was checked for a concentration range between 25 ng.mL-1 and 1000 ng.mL-1. Intra- and inter-day precision had relative standard deviation lower than 10% and 15%, respectively. Recovery from plasma was higher than 90%. Accuracy values were 98.21%, 99.70%, and 102.70% for lower, medium, and upper limits of quantification, respectively. Limit of quantification was 25 ng.mL-1. Drug stability was analyzed at room temperature using plasma kept in a freezer at -80 °C for 45 days after processing for 6 h and three freeze-thaw cycles. The advantages of the method developed include stability under different conditions and low limit of quantification. Its applicability was confirmed by the analysis of raloxifene levels in plasma samples in a designed pharmacokinetic study in rats after intravenous administration (5 mg.kg-1).

HIV/AIDS treatment and physicochemical quality control of medicines: evaluation of non-generic lamivudine + zidovudine tablets manufactured in Brazil

In this work it was evaluated the physicochemical quality of lamivudine + zidovudine tablets, whose association belongs to the list of drugs distributed by the Brazil's National Program on Sexually Transmitted Diseases and AIDS. Four non-generic products (lamivudine + zidovudine tablets) were analyzed. They were obtained from different Brazilian manufacturers, besides a reference product. The quality was evaluated by physicochemical tests described in the official codes. A validated reversed-phase high performance liquid chromatography (HPLC) method was used for the assay of the active substances. All samples were in accordance to the requisites in relation to their physicochemical characteristics. Dissolution studies showed similar drug percentual dissolved among all samples. The results reflect the interest of the national pharmaceutical industry to ensure the delivery of safer and cheaper drugs to the Brazilian people, with particular importance in the National Program on Sexually Transmitted Diseases and AIDS.