Table 2: Result of stability, dilution integrity, matrix effect and ruggedness.CPD as an anticoagulant in polypropylene tubes. The stability ranged from 99.1% to 101.3%, which are within limits (Table 2).
Stock solution stability at room temperatureStock solution stability at room temperature was performed by storing S-amlodipine and internal standard (Tizanidine) stock solutions at room temperature. The evaluation of stability was done by assaying six replicate injections of appropriately prepared dilutions of stored stock aliquot solutions of S-amlodipine and internal standard (Tizanidine) against six replicate injection of appropriately prepared dilution from fresh stock solutions of S-amlodipine and internal standard (Tizanidine) .The stock solution of S-amlodipine and internal standard (Tizanidine) was found to be stable, when stored at room temperature. The percent stability of the stock solution stability was 97.5% and 103.3% respectively, which are within limits (Table 2).
Dilution integrityDilution Integrity was determined by assaying four replicates QCs spiked approximately two times the concentration of ULOQ. Samples were diluted by an appropriate factor (two) prior to extraction, against freshly spiked calibration standard samples. The accuracy for two times diluted concentration was 101.9% and four times diluted concentration were 101.2% for S-amlodipine .The precision for two times diluted concentration were 4.0% and four times diluted concentration were 2.8% for S-amlodipine , which are within limits (Table 2).
Matrix effectMatrix effect was calculated by spiking analyte and IS at LQC and HQC levels into each of blank plasma extracts from six different batches of matrix respectively and analyzed in duplicate against six replicate injections of aqueous samples at low and high QCs samples. At low and QCs samples, the % coefficient of variation for matrix factor was found to be 9.35% and 6.84%, respectively for S-amlodipine which is within limits (Table 2).
RuggednessThe ruggedness of the extraction procedure and chromatographic method was evaluated by analysis of a batch of six sets of quality control samples and a set of calibration standards using different column (same type) by another analyst. The within batch accuracy ranged from 107.1% to111.4% and within batch precision ranged from 1.8% to 4.7% for S-amlodipine .The results indicated that the batch met the acceptance criteria of linearity, precision and accuracy data of the quality control samples, which are within limits (Table 2).
Stock solution stability at refrigerated temperature (4.0 days)Stock solution stability at refrigerated temperature was performed by S-amlodipine and internal standard (Tizanidine) stock solutions at refrigerated temperature. The evaluation of stability was done by assaying six replicates injections of appropriately prepared dilution from stored aliquot solutions of S-amlodipine and internal standard (Tizanidine) against six replicate injection of appropriately prepared dilution from fresh stock solutions of S-am...