Manidipine: A different dihydropyridine

Enantioselective determination of R-(-)-manidipine and S-(+)-manidipine in human plasma by a sensitive and selective chiral LC-MS/MS assay

A sensitive and selective liquid chromatography-tandem mass spectrometric (LC-MS/MS) assay method has been developed and validated for the enantioselective determination of manidipine in human plasma using isotope-labeled compounds as internal standards. After solid-phase extraction, R-(-)-manidipine and S-(+)-manidipine were chromatographed on a Chiralpack IC-3 C₁₈ column using a isocratic mobile phase composed of 2 mm ammonium bicarbonate and acetonitrile (15:85, v/v). The precursor ion to product ion transitions for the enantiomers and internal standards were monitored in the multiple reaction monitoring and positive ionization mode using an API-4000 mass spectrometer. The method was linear over the concentration range of 0.05-10.2 ng/mL for both enantiomers. The precision and accuracy results over five concentration levels in five different batches were well within the acceptance limits. The mean extraction recovery was >80% for both enantiomers. A variety of stability tests were executed in plasma and in neat samples, which complies with the FDA guidelines. After complete validation, the method was successfully applied to a pharmacokinetic study of a manidipine 20 mg oral dose in 10 healthy South India subjects under fasting conditions. The assay reproducibility is shown through incurred samples reanalysis of 20 subject plasma samples.

Effects of manidipine plus rosuvastatin versus olmesartan plus rosuvastatin on markers of insulin resistance in patients with impaired fasting glucose, hypertension, and mixed dyslipidemia

AIM

To compare the effect of manidipine 20 mg plus rosuvastatin 10 mg versus olmesartan 20 mg plus rosuvastatin 10 mg on markers of insulin resistance in patients with mixed dyslipidemia, hypertension, and impaired fasting glucose (IFG).

METHODS

This study had a prospective, randomized, open-label, blinded endpoint (PROBE) design. A total of 40 patients with IFG, mixed dyslipidemia, and stage 1 hypertension were included. Following dietary intervention, patients were randomly allocated to rosuvastatin (10 mg/d) plus olmesartan (20 mg/d) or manidipine (20 mg/d). The primary end point was the between-group difference in changes in the Homeostasis Model Assessment Insulin Resistance (HOMA-IR) index following 3 months of treatment. Secondary end points included changes in fasting plasma glucose (FPG), fasting insulin levels, and glucosylated hemoglobin.

RESULTS

At the end of the 3-month treatment period, a significant increase in HOMA-IR index by 14% (from 2.4 [0.5-7.9] to 2.7 [0.5-5.2], P = .02 versus baseline) was seen in the olmesartan plus rosuvastatin group. On the contrary, no significant change in HOMA-IR index was observed in the manidipine plus rosuvastatin group (1.7 [0.5-5.2] to 1.7 [0.8-6.0], P = NS versus baseline, P = .04 versus olmesartan plus rosuvastatin group). An increase in fasting insulin levels was observed in the olmesartan plus rosuvastatin group (+8%, from 10.1 [2.0-29.6] to 10.9 [2.0-19.1] μU/mL, P < .05 versus baseline), while no significant change was seen in the manidipine plus rosuvastatin group (+3%, from 7.3 [2.0-17.6] to 7.5 [1.9-15.6] μU/mL, P = NS versus baseline, P = .02 versus olmesartan plus rosuvastatin group). Fasting plasma glucose and glycosylated hemoglobin did not change significantly in any group.

CONCLUSION

Manidipine seems to ameliorate the possible statin-associated increase in insulin resistance as compared with olmesartan in patients with IFG, hypertension, and mixed dyslipidemia.