Pharmacokinetics of nifedipine in Taiwanese

Abstract

To elucidate the pharmacokinetics of nifedipine in Taiwanese, a retrospective review of nifedipine bioequivalence studies completed in Taiwan in the past 5 years was conducted. A total of 198 healthy male volunteers were given a single dose of a 10 mg Adalat capsule as a reference drug after overnight fasting. Pharmacokinetic parameters derived from Adalat administration were calculated by non-compartmental analysis with the WinNonlin program. After oral administration of an immediate-release dosage form of a 10 mg nifedipine capsule to Taiwan residents, a skewed distribution with no clear evidence of bimodality of pharmacokinetic parameters was observed. The mean Cmax was 143.12+/-53.48 ng/ml, the mean AUC was 293.77+/-115.62 ng.h/ml, the mean T1/2 was 3.08+/-1.61 h, and the median value of Tmax was 0.61 h. Compared with other published studies, the Cmax and AUC of nifedipine after 10 mg administration were significantly higher in Taiwanese than in British and American subjects. However, the Cmax and AUC were similar to those of Indian and Mexican subjects. According to the antimode of AUC distribution of 22.5 ng.h/ml/mg proposed by Kleinbloesem, 69.7% of Taiwanese can be categorized as slow metabolizers. Based on the results in this study, the majority of Taiwanese show lower activity of nifedipine metabolism.

Development of an HPLC method for determination of diphenidol in plasma and its application in an oral multi-dose bioequivalence study in a healthy female mexican population

“…3), although the C max obtained in this study was similar to that reported in the drug information for prescription [1]. The half-life obtained in this Mexican population is 3 h, which is slightly lower than that reported in references (4.0 h) [1] and suggesting that Mexican population may eliminate DPN faster than other populations, such as is suggested for other drugs and populations [12][13][14][15].…”

“…Our rather simple analytical HPLC-UV method for determination of DPN in human plasma was demonstrated to be precise and accurate it can be successfully used in pharmacokinetic or bioequivalence studies and for continuous drug monitoring under a multi-dose administration regime. This pharmacokinetic data of DPN in Mexicans has not been previously reported, suggesting differences in pharmacokinetic profiles linked with ethnic genotype composition [12][13][14][15]. Finally, both oral formulations tested containing 25 mg of DPN and manufactured in Mexico are bioequivalent.…”

Progesterone blocks multiple routes of ion flux

“…However, concentrations of even a low dose of an administered dihydropyridine (e.g. 10–20 mg) can approach micromolar levels with any one of several contributing factors, such as advanced age, use of H 2 -receptor antagonists and/or being of non-caucasian lineage (Renwick et al, 1988; Chien et al, 2004; Ahmad et al, 2009; Robertson et al, 1988; Kahn et al, 1991). As such, it has been postulated that dihydropyridines may act within the CNS of patients to affect these additional channels and receptors (Das et al, 2004).…”

CPU0213, A NON‐SELECTIVE ETA/ETB RECEPTOR ANTAGONIST, IMPROVES PULMONARY ARTERIOLAR REMODELING OF MONOCROTALINE‐INDUCED PULMONARY HYPERTENSION IN RATS

“…Thus, the severity of the pathology of the PH between the two studies is different. Second, amlodipine has a longer half‐life 28,29 than nifedipine 30 (3.08 ± 1.61 vs 0.93–01.12 h, respectively). Both these factors may contribute to the differences in the effects between nifedipine and amlodipine in attenuating PH 28 …”