A Randomized, Placebo Controlled, Double Blind, Parallel Group, Multiple Dosing, Dose Escalation Clinical Study to Evaluate Pharmacokinetics/Pharmacodynamics and Tolerability of Zofenopril in Healthy Korean Subjects

BACKGROUND: Zofenopril is a new Angiotensin Converting Enzyme (ACE) inhibitor for the treatment of the patients with hypertension and congestive heart failure. This study aimed to evaluate the pharmacokinetics (PKs)/pharmacodynamics (PDs) and tolerability of zofenopril in healthy Korean subjects. METHODS: A randomized, double blind, placebo-controlled, multiple dosing parallel group study with two dosage groups (zofenopril 30 mg or 60 mg) was conducted in healthy Korean male subjects. Each dosage group consisted of 10 subjects and they were randomly assigned to receive zofenopril or placebo with a ratio of 4:1. PK characteristics of zofenopril and its active metabolite, zofenoprilat, were evaluated after single or multiple dosing. Serum ACE activities and blood pressures were measured for PD evaluation. Adverse events, clinical laboratory tests, electrocardiograms, vital signs and physical examinations were performed for tolerability evaluation. RESULTS: The PK characteristics of zofenopril and zofenoprilat after single dose and multiple doses were similar to one another. The metabolic ratio of zofenoprilat to zofenopril after single dose and multiple doses were 12.4 and 14.9, respectively, in the 30 mg dosage group, and were 6.8 and 6.6, respectively, in the 60 mg dosage group. Complete serum ACE activity inhibition was observed within 1 hour in both doses but it was maintained longer in the 60 mg dosage group compared to the 30 mg dosage group. There were no clinically significant abnormalities in tolerability evaluations. CONCLUSION: The PK/PD characteristics of zofenopril and zofenoprilat after single or multiple administrations were explored. Zofenopril was well tolerated after multiple administrations in healthy Korean subjects.

Determination of zofenopril and its active metabolite zofenoprilat by a new derivative LC-MS method and their pharmacokinetics in healthy Chinese volunteers / 中国药科大学学报

Aim: A new derivative LC-MS method was developed for the simultaneous determination of zofenopril and its active metabolite zofenoprilat to investigate the pharmacokinetic characteristics of zofenopril and zofenopri-lat in healthy Chinese volunteers after single and multiple oral doses of zofenopril calcium tablets. Methods: Ten Chinese healthy volunteers were given three single oral doses of 15,30, and 60 mg, respectively, and consecutively the multiple doses of 30 mg. The concentration and pharmacokinetic parameters of both the parent drug and the active metabolite were simultaneously determined by derivative LC-MS method using p-bromophenacyl bromide (p-BPB) as the derivative reagent. Results: After the single oral administrations of 15, 30, and 60 mg of zofeno-pril calcium, there was no significant difference in the t_(1/2) of both zofenopril and zofenoprilat among the three do-ses. The values of AUC_(0-24h) and c_(max) for both zofenopril and zofenoprilat showed the good linearities to the dosage over the dose range from 15 mg to 60 mg. There were no significant differences in AUC_(0-24h) and c_(max) for both com-pounds between female and male volunteers. After multiple oral administration( 30 mg once daily for 6 days ), the average steady state plasma concentration( c_(av)) for zofenopril was (5. 07 ±1. 06) ng/mL with the degree of fluctu-ation (DF) of 14. 26 ± 2. 94. The c_(av) for zofenoprilat was (6. 28 ± 1. 87) ng/mL with the DF of 11. 61 ±4. 68. The accumulation index values for zofenopril and zofenoprilat were 0. 94 ± 0. 31 and 0. 83±0. 13, respec-tively. Conclusion: Both zofenopril and zofenoprilat were demonstrated of linear kinetics after single administra-tion and showed no accumulation after multiple administration of the test zofenopril calcium tablets. There was significant difference in the pharmacokinetic characteristics for zofenopril calcium between healthy Chinese and European volunteers.