An improved LC‐MS/MS method for quantitation of indapamide in whole blood: application for a bioequivalence study

Abstract

An improved LC-MS/MS method for the quantitation of indapamide in human whole blood was developed and validated. Indapamide-d3 was used as internal standard (IS) and liquid-liquid extraction was employed for sample preparation. LC separation was performed on Synergi Polar RP-column (50 × 4.6 mm i.d.; 4 µm) and mobile phase composed of methanol and 5 mm aqueous ammonium acetate containing 1 mm formic acid (60:40), at flow rate of 1 mL/min. The run time was 3.0 min and the injection volume was 20 μL. Mass spectrometric detection was performed using electrospray ion source in negative ionization mode, using the transitions m/z 364.0 → m/z 188.9 and m/z 367.0 → m/z 188.9 for indapamide and IS, respectively. Calibration curve was constructed over the range 0.25-50 ng/mL. The method was precise and accurate, and provided recovery rates >80% for indapamide and IS. The method was applied to determine blood concentrations of indapamide in a bioequivalence study with two sustained release tablet formulations. The 90% confidence interval for the geometric mean ratios for maximum concentration was 95.78% and for the area under the concentration-time curve it was 97.91%. The tested indapamide tablets (Eurofarma Laboratórios S.A.) were bioequivalent to Natrilix®, according to the rate and extent of absorption.

Simultaneous determination of indapamide, perindopril and perindoprilat in human plasma or whole blood by UPLC-MS/MS and its pharmacokinetic application

“…Three freeze-thaw cycles, long-term storage at − 80 °C for one month and short-term stability of the biological samples did not result in obvious changes in the drug concentration, as earlier publications have reported [9] , [10] , [11] , [12] , [13] , [14] , [18] . And the stability results of analytes after 30 h in autosampler at 8 °C were within 85%–115% of the actual concentration ( Tables S9 and S10 ).…”

“… Drug Dose (mg) C max (ng/mL) T max (h) AUC 0-t (ng·h/mL) Refs. Indapamide 1.25 62.0 ± 10.8 1.6 ± 0.6 882 ± 126 This study 1.25 56.2 ± 14.0 2.4 ± 1.1 1152 ± 429 [16] 1.5 43.6 ± 16.1 10.3 ± 5.3 1318 ± 303 [11] a 1.5 41.1 ± 7.6 8.0 ± 3.0 1268 ± 279 [21] a Perindopril 4 48.0 ± 16.2 0.65 ± 0.1 51.4 ± 12.8 This study 4 36.5 ± 11.4 0.66 ± 0.2 41.7 ± 10.0 [16] 4 63.9 ± 18.0 0.66 ± 0.2 70.3 ± 14.4 [22] 4 72 ± 20 0.75 106 ± 32 [24] Perindoprilat 4 5.96 ± 3.0 6.4 ± 1.3 108 ± 34.7 This study 4 5 ± 2 4.3 ± 2.9 92 ± 30 [23] b 4 5.91 ± 2.9 6.3 ± 1.2 111 ± 18.4 [22] 4 4.9 ± 2.7 6 191 ± 76 [24] AUC 0-t : in this study t = 48 h for inda...…”

“…As it was mentioned in Introduction, several methods have been reported for the determination of perindopril and perindoprilat or indapamide in biological samples [9] , [10] , [11] , [12] , [13] , [14] , [15] , [16] . However, most of the reported methods involved only one or two analytes in one biofluid.…”

“…The results were in close agreement with the earlier reported values for pharmacokinetic study of two fixed dose combination formulations [16] . The T max and AUC 0-t of indapamide in whole blood showed disparity after oral administration of indapamide tablets (1.5 mg) individually [11] , [21] , which may be attributed to the different dosage forms as it has been reported that the co-administration of perindopril and indapamide does not change their pharmacokinetic properties [5] . In regard to pharmacokinetic results of perindopril and perindoprilat in plasma, they were in close proximity when compared to the others found in the literature [22] , [23] .…”

“…Several LC-MS/MS methods have been reported for the pharmacokinetic studies on perindopril and perindoprilat or indapamide individually in biological samples [9] , [10] , [11] , [12] , [13] , [14] . However, only a few pharmacokinetic studies on perindopril tert-butylamine/indapamide compound tablets have been reported [15] , [16] .…”