Inter-day accuracy and precision were also assessed from the analysis of the same QC samples on three separate occasions in replicate (n = 6). QC samples were analyzed against calibration standards. During the course of study the probability of encountering samples with concentrations above the upper limit of quantitation (ULOQ) could not be ruled out and therefore dilution with drug free plasma is necessary to bring them within the calibration range. To establish the effect of dilution on the integrity of samples, six aliquots MLN0128 mw of 63001.36 ng/mL and 12370.35 ng/mL of AMX and CLV respectively were prepared.
The samples were subjected to twofold dilution (n = 6) and fivefold dilution (n = 6) with drug free human plasma to bring them within the Perifosine in vitro calibration range. The samples were processed, analyzed and the concentrations obtained were compared with theoretical values. Evaluation of the stability of samples was based on the comparison of various samples against freshly prepared samples of the same concentration. Percentage difference between the back calculated concentrations obtained for the sample under investigation
and freshly prepared sample was evaluated. Six aliquots, each of LQC and HQC concentrations were used for stability study. Bench top stability was studied on samples kept at ambient temperature (20–30 °C) for 6 h 26 min. The processed samples were kept in the autosampler at 5 °C for 59 h 33 min and then injected to determine the stability in the autosampler. The freeze–thaw stability of samples stored at −80 °C was studied after subjecting the samples to five freeze–thaw cycles. The long term stability of the samples were determined after storing the samples at −80 °C for 28 days. In order to determine the stability of AMX and CLV in solution, the working solution was kept at 2–8 °C for 9 days 22 h. Thereafter, because the mean areas of AMX and CLV from six
replicate chromatographic runs were compared to that of the mean area of a freshly prepared solution of the same concentration. For the pharmacokinetic studies co-amoxiclav a single dose of 875/125 mg tablets was administered orally. 24 healthy adult male volunteers who gave written informed consent took part in this study. The study was approved by Ethics Committee of Institutional Review Board. The volunteers were selected on predetermined inclusion/exclusion criteria. Males had a mean age of 27.19 ± 6.32 years, mean weight of 60.87 ± 7.07 kg, mean height of 167.87 ± 5.53 cm and a body mass index mean of 21.57 ± 1.93 kg/cm2. The volunteers who were included in the study have not taken any other medication for at least two weeks beforehand. Blood samples were taken by using vacutainers, precoated with sodium heparin, at 0.00, 0.25, 0.50, 0.75, 1.00, 1.25, 1.50, 1.75, 2.00, 2.25, 2.50, 2.75, 3.00, 3.25, 3.50, 3.75, 4.00, 5.00, 6.00, 7.00, 8.00, 10.00, and 12.00 h after ingestion.