RESUMO
This study aimed to investigate the impact of storage conditions on the dissolution performance of commercial metronidazole (MTZ) tablets available in Saudi Arabia; these were coded as the reference and Test A, Test B, and Test C products. Moreover, the hardness and the disintegration time were measured. The UV spectrophotometrically analytical technique was utilized to quantify MTZ. All the control tablets, which were tested upon receipt, met the USP requirement as not less than 85 % of the labeled amount of MTZ was dissolved in 60 min. The MTZ reference released 91.79 % ± 1.23 after 60 min, while the products A, B, and C released 87.96 % ± 2.60, 93.26 % ± 2.01, and 88.61 % ± 2.04, respectively. The different dissolution parameters calculated for all the control tablets showed that the MTZ products A and B had optimal dissolution performances and were considered similar to the reference product. The product C showed a significantly reduced dissolution performance and was considered different from the reference. The in vitro dissolution of the MTZ tablets stored at 40oC ± 2 oC/75 % RH ± 5 % for 6 months indicated that the tablets maintained compliance with the USP requirement. The MTZ reference released 89.36 % ± 3.64 after 60 min, while the products A, B, and C released 95.79 % ± 3.91, 88.52 % ± 2.52, and 87.79 % ± 5.04, respectively. However, a slight reduction in the percentage released after 30 min (% DE30) and a slight increase in the mean dissolution time (MDT) were observed during the first 3 months of storage under stressed conditions. These changes were more obvious after 6 months of storage under the same conditions. Furthermore, in vitro dissolution of the product C stored at 40oC ± 2 oC/75 % RH ± 5 % for 3 months with further protection against high humidity revealed an improvement in the dissolution parameters due to the similar protective effects exerted by the two packaging forms. Furthermore, the study shows that storage conditions such as humidity and temperature affect in vitro dissolution of MTZ marketed tablets which may have an impact on efficiency and patient safety.
RESUMO
A unique, easy, precise and exact high-performance liquid chromatographic-mass tandem (LCMS/MS) approach was created and validated for the measurement of the antihypertensive medicine Lisinopril (LIS) in dried blood spots (DBS). This was the first time according to our knowledge that LIS is being validated in DBS. Liquid chromatography mass tandem was utilized using the Water Acquity column as UPLC -HSS T3® column. Ten millimole ammonium formate, 0.2 percent formic acid, 0.2 percent trimethylamine, one percent acetonitrile (pH 3.0± 0.02) used as mobile phase (A) and a mobile phase (B) consisting of 0.2 percent formic acid in acetonitrile. The mobile phase lasts for 2.5 minutes at a flow rate of 0.2 ml/min. For the drug as well internal standard, the retention times (RT) obtained under optimal circumstances were 0.63±0.02 and 2.18±0.03 min, dried blood spot samples, offering consistent and quantitative drug recovery. The process was the shortest RT reported for the LIS, it is a linear relationship with concentrations from 10 - to 100ng/ml. A protein precipitation approach was used to measure the LIS. The method used to analyze DBS samples from rats receiving LIS.
