Bioequivalence of two tablet formulations of clopidogrel in healthy Argentinian volunteers: a single-dose, randomized-sequence, open-label crossover study

Comparative Bioequivalence Study of 2 Clopidogrel 75-mg Tablet Formulations in Moroccan Volunteers

This study investigates the pharmacokinetic properties and bioequivalence of 2 formulations of clopidogrel tablets administered to a cohort of healthy Moroccan male volunteers. The primary objective was to assess the rate and extent of drug absorption from the test formulation in comparison to a reference formulation, focusing on critical parameters including maximum plasma concentration (Cmax), area under the concentration-time curve from 0 to the last measurable time (AUC0-t), and area under the concentration-time curve extrapolated to infinity (AUC0-∞). The results revealed that the geometric mean ratios of Cmax, AUC0-t, and AUC0-∞ for the test formulation relative to the reference formulation were 105.7%, 105.6%, and 105.6%, respectively. The 90% confidence intervals for these parameters fell within the predefined bioequivalence range of 80%-125%, indicating a statistically and clinically equivalent performance between the 2 formulations. This investigation sheds light on the pharmacokinetic behavior of clopidogrel in the context of the Moroccan male population, offering valuable insights into the comparability of formulations.

Physiologically Based Pharmacokinetic (PBPK) Modeling of Clopidogrel and Its Four Relevant Metabolites for CYP2B6, CYP2C8, CYP2C19, and CYP3A4 Drug–Drug–Gene Interaction Predictions

The antiplatelet agent clopidogrel is listed by the FDA as a strong clinical index inhibitor of cytochrome P450 (CYP) 2C8 and weak clinical inhibitor of CYP2B6. Moreover, clopidogrel is a substrate of—among others—CYP2C19 and CYP3A4. This work presents the development of a whole-body physiologically based pharmacokinetic (PBPK) model of clopidogrel including the relevant metabolites, clopidogrel carboxylic acid, clopidogrel acyl glucuronide, 2-oxo-clopidogrel, and the active thiol metabolite, with subsequent application for drug–gene interaction (DGI) and drug–drug interaction (DDI) predictions. Model building was performed in PK-Sim^® using 66 plasma concentration-time profiles of clopidogrel and its metabolites. The comprehensive parent-metabolite model covers biotransformation via carboxylesterase (CES) 1, CES2, CYP2C19, CYP3A4, and uridine 5′-diphospho-glucuronosyltransferase 2B7. Moreover, CYP2C19 was incorporated for normal, intermediate, and poor metabolizer phenotypes. Good predictive performance of the model was demonstrated for the DGI involving CYP2C19, with 17/19 predicted DGI AUC_last and 19/19 predicted DGI C_max ratios within 2-fold of their observed values. Furthermore, DDIs involving bupropion, omeprazole, montelukast, pioglitazone, repaglinide, and rifampicin showed 13/13 predicted DDI AUC_last and 13/13 predicted DDI C_max ratios within 2-fold of their observed ratios. After publication, the model will be made publicly accessible in the Open Systems Pharmacology repository.

Evaluation of the effect of carrier material on modification of release characteristics of poor water soluble drug from liquisolid compacts

Liquisolid compact is a novel dosage form in which a liquid medication (liquid drug, drug solution/dispersion in non-volatile solvent/solvent system) is converted to a dry, free flowing powder and compressed. Objective of the study was to elucidate the effect of carrier material on release characteristics of clopidogrel from liquisolid compacts. Different formulations of liquisolid compacts were developed using microcrystalline cellulose, starch maize, polyvinyl pyrollidone and hydroxypropyl methylcellulose as carrier material in three concentrations (40, 30 and 20%, w/w). Liquid vehicle was selected on the basis of solubility of clopidogrel. Colloidal silicondioxide was used as coating material and ratio of carrier to coating material was kept 10. A control formulation comprised of microcrystalline cellulose (diluents), tabletose-80 (diluents), primojel (disintegrant) and magnesium stearate (lubricant) was prepared by direct compression technique and was used for comparison. All the formulations were evaluated at pre and post compression level. Acid solubility profile showed higher solubility in HCl buffer pH2 (296.89±3.49 μg/mL). Mixture of propylene glycol and water (2:1, v/v) was selected as liquid vehicle. Drug content was in the range of 99–101% of the claimed quantity. All the formulations showed better mechanical strength and their friability was within the official limits (<1%). Microcrystalline cellulose and starch maize resulted in faster drug release while polyvinyl pyrollidone and HPMC resulted in sustaining drug release by gel formation. It is concluded from results that both fast release and sustained release of clopidogrel can be achieved by proper selection of carrier material.

Generic versus brand-name drugs used in cardiovascular diseases

This meta-analysis aimed to compare the efficacy and adverse events, either serious or mild/moderate, of all generic versus brand-name cardiovascular medicines. We searched randomized trials in MEDLINE, Scopus, EMBASE, Cochrane Controlled Clinical Trial Register, and ClinicalTrials.gov (last update December 1, 2014). Attempts were made to contact the investigators of all potentially eligible trials. Two investigators independently extracted and analyzed soft (including systolic blood pressure, LDL cholesterol, and others) and hard efficacy outcomes (including major cardiovascular adverse events and death), minor/moderate and serious adverse events. We included 74 randomized trials; 53 reported ≥1 efficacy outcome (overall sample 3051), 32 measured mild/moderate adverse events (n = 2407), and 51 evaluated serious adverse events (n = 2892). We included trials assessing ACE inhibitors (n = 12), anticoagulants (n = 5), antiplatelet agents (n = 17), beta-blockers (n = 11), calcium channel blockers (n = 7); diuretics (n = 13); statins (n = 6); and others (n = 3). For both soft and hard efficacy outcomes, 100 % of the trials showed non-significant differences between generic and brand-name drugs. The aggregate effect size was 0.01 (95 % CI -0.05; 0.08) for soft outcomes; -0.06 (-0.71; 0.59) for hard outcomes. All but two trials showed non-significant differences in mild/moderate adverse events, and aggregate effect size was 0.07 (-0.06; 0.20). Comparable results were observed for each drug class and in each stratified meta-analysis. Overall, 8 serious possibly drug-related adverse events were reported: 5/2074 subjects on generics; 3/2076 subjects on brand-name drugs (OR 1.69; 95 % CI 0.40-7.20). This meta-analysis strengthens the evidence for clinical equivalence between brand-name and generic cardiovascular drugs. Physicians could be reassured about prescribing generic cardiovascular drugs, and health care organization about endorsing their wider use.

Development and validation of an HPLC-MS/MS method to determine clopidogrel in human plasma

A quantitative method for clopidogrel using online-SPE tandem LC–MS/MS was developed and fully validated according to the well-established FDA guidelines. The method achieves adequate sensitivity for pharmacokinetic studies, with lower limit of quantifications (LLOQs) as low as 10 pg/mL. Chromatographic separations were performed on reversed phase columns Kromasil Eternity-2.5-C18-UHPLC for both methods. Positive electrospray ionization in multiple reaction monitoring (MRM) mode was employed for signal detection and a deuterated analogue (clopidogrel-d₄) was used as internal standard (IS). Adjustments in sample preparation, including introduction of an online-SPE system proved to be the most effective method to solve the analyte back-conversion in clinical samples. Pooled clinical samples (two levels) were prepared and successfully used as real-sample quality control (QC) in the validation of back-conversion testing under different conditions. The result showed that the real samples were stable in room temperature for 24 h. Linearity, precision, extraction recovery, matrix effect on spiked QC samples and stability tests on both spiked QCs and real sample QCs stored in different conditions met the acceptance criteria. This online-SPE method was successfully applied to a bioequivalence study of 75 mg single dose clopidogrel tablets in 48 healthy male subjects.

Development and Validation of an HPLC Method for Simultaneous Quantification of Clopidogrel Bisulfate, Its Carboxylic Acid Metabolite, and Atorvastatin in Human Plasma: Application to a Pharmacokinetic Study

A simple, sensitive, and specific reversed phase liquid chromatographic method was developed and validated for simultaneous quantification of clopidogrel, its carboxylic acid metabolite, and atorvastatin in human serum. Plasma samples were deproteinized with acetonitrile and ibuprofen was chosen as internal standard. Chromatographic separation was performed on an BDS Hypersil C18 column (250 × 4.6 mm; 5 μm) via gradient elution with mobile phase consisting of 10 mM phosphoric acid (sodium) buffer solution (pH = 2.6 adjusted with 85% orthophosphoric acid) : acetonitrile : methanol with flow rate of 1 mL·min(-1). Detection was achieved with PDA detector at 220 nm. The method was validated in terms of linearity, sensitivity, precision, accuracy, limit of quantification, and stability tests. Calibration curves of the analytes were found to be linear in the range of 0.008-2 μg·mL(-1) for clopidogrel, 0.01-4 μg·mL(-1) for its carboxylic acid metabolite, and 0.005-2.5 μg·mL(-1) for atorvastatin. The results of accuracy (as recovery) with ibuprofen as internal standard were in the range of 96-98% for clopidogrel, 94-98% for its carboxylic acid metabolite, and 90-99% for atorvastatin, respectively.

Assessment of the efficacy and tolerability of clopidogrel napadisilate in Korean patients with coronary stenting: a multicenter, prospective, open-label, randomized trial

OBJECTIVE

Clopidogrel is indicated for the treatment and prevention of peripheral vascular, cerebrovascular, and coronary artery diseases. This clinical trial was designed to demonstrate that clopidogrel napadisilate (CN) is not inferior to clopidogrel bisulfate (CB) with respect to its effectiveness in inhibiting platelet aggregation.

METHODS

This 4 week multi-center, prospective, open-label, randomized trial was conducted at five clinical centers in South Korea. Patients were randomized into the 75 mg CN group or the 75 mg CB group. Platelet aggregation was assessed by the VerifyNow assay. The primary outcome was the difference of the percentage P2Y12 inhibition and the secondary outcome was the baseline and change in P2Y12 reaction units (PRU).

RESULTS

There was no significant difference in the percentage P2Y12 inhibition (CN vs. CB, 34.92 ± 21.33% vs. 30.43 ± 17.90%, p=0.203). The mean difference of the percentage P2Y12 inhibition between groups was 4.49%, their two-sided 95% confidence interval was -2.45% to 11.44%, and the lower bound (-2.45%) was greater than the acceptable non-inferiority margin of -9.0%. The baseline PRU was 96.67 ± 76.76 in the CN group and 216.95 ± 68.86 in the CB group (p=0.121), and the change in the PRU was -3.32 ± 51.71 in the CN group and 10.52 ± 43.31 in the CB group (p=0.106). Four subjects experienced AEs (6.3%, 5 events) in the CN group and 7 subjects (11.11%, 13 events) in the CB group without statistical significance (p=0.364). With respect to serious adverse events, 2 events were reported in 2 subjects, 1 in each group.

CONCLUSION

Clopidogrel napadisilate was not inferior to clopidogrel bisulfate in terms of antiplatelet efficacy and tolerability, and there were no clinically significant adverse events.

Clinical pharmacokinetics of clopidogrel and its metabolites in patients with cardiovascular diseases

Background and Objective

Approximately 5–40 % of patients treated with clopidogrel do not display an adequate antiplatelet response. Clopidogrel resistance may be caused by insufficient drug absorption or impaired metabolic activation of the drug. The aim of this study was to evaluate the pharmacokinetics of clopidogrel and its metabolites in plasma samples from patients treated with high and low doses of clopidogrel, to obtain a possible explanation for antiplatelet resistance.

Methods

The study included patients receiving either a single 300 mg loading dose of clopidogrel (n = 17) or a 75 mg dose (n = 45) for at least 7 days before sample collection. The concentrations of clopidogrel and its metabolites—the inactive H3 and the pharmacologically active H4 isomers of the thiol metabolite and the inactive carboxylic acid metabolite—in plasma samples (stabilized with 2-bromo-3′-methoxyacetophenone) from three patients after 300 mg and from 41 patients after 75 mg of the drug were determined using a validated high-performance liquid chromatography method with tandem mass spectrometry. The non-stabilized samples from the remaining patients were analysed using a validated capillary electrophoresis method. The calculated concentrations were used to determine the pharmacokinetic parameters of the analytes. The pharmacodynamic response to clopidogrel treatment, expressed as adenosine diphosphate-induced platelet aggregation, was measured using a Multiplate analyser.

Results

The pharmacokinetic parameter values for the H3 and H4 isomers determined in the studied group of patients treated with clopidogrel 75 mg (maximum plasma concentration [C_max] 5.29 ± 5.54 and 7.13 ± 6.32 ng/mL for H3 and H4, respectively; area under the plasma concentration-time curve from time zero to time t [AUC_t] 7.37 ± 6.71 and 11.30 ± 9.58 ng·h/mL for H3 and H4, respectively) were lower than those reported in healthy volunteers, according to the literature data. Platelet aggregation measured with a Multiplate analyser ranged between 37 and 747 AU·min. A significant correlation was found between the C_max of the active H4 isomer and platelet aggregation (p = 0.025).

Conclusion

The C_max of the active H4 isomer and platelet aggregation measured by the Multiplate analyser may serve as markers of the patient response to clopidogrel therapy.

Clustering of Acute and Subacute Stent Thrombosis Related to the Introduction of Generic Clopidogrel

Introduction:

Generic clopidogrel recently became available in the United States and was rapidly adopted as a cost-effective alternative to the brand name formulation. However, unlike other medications, subtle differences in clopidogrel bioavailability may lead to acute consequences including stent thrombosis (ST).

Materials and Methods:

We studied the incidence of acute and subacute ST during the initial period of generic clopidogrel use (June 18, 2012-September 6, 2012 [80 days]) at a single percutaneous coronary intervention (PCI) center. There were 4 definite ST cases within 30 days of successful PCI in patients receiving generic clopidogrel, which were compared to historic control ST cases from 80 days prior to generic clopidogrel use and for 3 years from June 18, 2009 to June 17, 2012.

Results:

During generic clopidogrel administration, 1054 PCIs were performed, giving a definite 30-day ST incidence of 0.38% (4 of 1054) among these patients. By comparison, there were 2 episodes of definite 30-day ST during the 80 days immediately preceding generic clopidogrel use (2 of 1114), while 3-year historic data indicated a definite 30-day ST incidence of 0.14% (20 of 14 432), representing a 2.7-fold increase in definite 30-day ST with generic clopidogrel use ( P = .076). Exclusion of 3 historic controls with a defined reason for ST (noncompliance, marked thrombocytosis) gave a 3.2-fold increase in 30-day ST with generic clopidogrel ( P = .050). An ST-predictive algorithm revealed no difference in the likelihood of ST between patients receiving generic clopidogrel and historic controls.

Conclusions:

We observed an unexpected >2-fold increase in ST coincident with generic clopidogrel use. Although we cannot ascribe causality, this observation warrants increased vigilance and close monitoring of patients receiving generic clopidogrel.

Branded versus generic clopidogrel in cardiovascular diseases: a systematic review

In the United States, patent for branded Plavix has recently expired. Some studies have compared branded and generic clopidogrel in terms of pharmacokinetic parameters in healthy volunteers, but data on patients and clinical outcomes are scarce. We aimed to review efficacy and safety data from studies comparing Plavix with generic clopidogrel in patients with cardiovascular disease. Electronic databases were searched (from inception to May 2012) for prospective studies evaluating branded versus generic clopidogrel in patients with cardiovascular diseases. Studies' characteristics and data estimates were retrieved. Pooled risk ratio (RR) and 95% confidence intervals (95% CIs) were estimated through a random-effects model. Three studies evaluating 760 patients were included: 2 randomized controlled trials and 1 cohort study. The RR for major cardiovascular events was 1.01 (95% CI, 0.67-1.52). Incidence of adverse events was similar between Plavix and generic (RR 0.85; 95% CI, 0.49-1.48). The risks of mortality, bleeding, and drug discontinuation were also not different between groups. There are a limited number of studies comparing Plavix and generic clopidogrel in patients with cardiovascular diseases and reporting hard clinical end points. The available evidence is therefore limited and does not support the existence of differences in efficacy or safety between branded and generic clopidogrel.

A randomized crossover study comparing the antiplatelet effect of plavix versus generic clopidogrel

BACKGROUND

Clopidogrel exists in different salt formulations. All published data that have demonstrated its beneficial effect are based entirely on the hydrogen sulphate salt contained in the branded product Plavix, which had US sales of $6.1 billion in 2010 alone. A number of cheaper generic versions of clopidogrel are increasingly being used in Europe as an alternative to Plavix, mainly for cost reasons. However, there is insufficient evidence to show that their pharmacodynamic effect is equivalent to Plavix.

METHODS

This prospective study investigated whether there is any significant difference in the antiplatelet effect of Plavix versus generic clopidogrel hydrochloride in healthy male volunteers. All participants received loading and maintenance doses of both drugs, in a crossover manner, separated by a 2-week washout period. Adenosine diphosphate (ADP)-induced platelet reactivity was measured using short thrombelastography at multiple timepoints.

RESULTS

The results showed interindividual heterogeneity in responses to clopidogrel but no significant difference in ADP-induced platelet reactivity between Plavix versus generic clopidogrel hydrochloride.

CONCLUSIONS

Our findings suggest comparable inhibition of ADP-induced platelet reactivity with Plavix and generic clopidogrel hydrochloride. This observation is particularly pertinent at a time when the patent for Plavix is expected to expire in the near future leading to the large-scale switch to cheaper generic preparations.

Quantitative determination of clopidogrel and its metabolites in biological samples: a mini-review

Clopidogrel has been applied in antiplatelet therapy since 1998 and is the thienopyridine with the largest clinical experience. By 2011, clopidogrel (Plavix(®)) was the second top-selling drug in the world. Following complete patent expiry in 2012/2013 its use is expected to grow even further from generics entering the market. Prefaced by a brief description of clopidogrel metabolism, this review analyzes analytical methods addressing the quantification of clopidogrel and its metabolites in biological samples. Techniques that have been applied to analyze human plasma or serum are predominantly LC-MS and LC-MS/MS. The lowest level of clopidogrel quantification that has been achieved is 5pg/mL, the shortest runtime is 1.5min and almost 100% recovery has been reported using solid-phase extraction for sample preparation.

A comparison of two brands of clopidogrel in patients with drug-eluting stent implantation

Background and Objectives

Although generic clopidogrel is widely used, clinical efficacy and safety between generic and original clopidogrel had not been well evaluated. The aim of this study was to evaluate the clinical outcomes of 2 oral formulations of clopidogrel 75 mg tablets in patients with coronary artery disease (CAD) undergoing drug-eluting stent (DES) implantation.

Subjects and Methods

Between July 2006 and February 2009, 428 patients that underwent implantation with DES for CAD and completed >1 year of clinical follow-up were enrolled in this study. Patients were divided into the following 2 groups based on treatment formulation, Platless® (test formulation, n=211) or Plavix® (reference formulation, n=217). The incidence of 1-year major adverse cardiovascular and cerebrovascular event (MACCE) and stent thrombosis (ST) were retrospectively reviewed.

Results

The baseline demographic and procedural characteristics were not significantly different between two treatment groups. The incidence of 1-year MACCEs was 8.5% {19/211, 2 deaths, 4 myocardial infarctions (MIs), 2 strokes, and 11 target vessel revascularizations (TVRs)} in Platless® group vs. 7.4% (16/217, 4 deaths, 1 MI, 2 strokes, and 9 TVRs) in Plavix® group (p=0.66). The incidence of 1-year ST was 0.5% (1 definite and subacute ST) in Platless® group vs. 0% in Plavix® group (p=0.49).

Conclusion

In this study, the 2 tablet preparations of clopidogrel showed similar rates of MACCEs, but additional prospective randomized studies with pharmacodynamics and platelet reactivity are needed to conclude whether generic clopidgrel may replace original clopidogrel.