Development and validation of a liquid chromatographic method for purity control of clopidogrel–acetylsalicylic acid in combined oral dosage forms

Effect of atmosphere and relative humidity on photodegradation of clopidogrel under artificial solar and indoor light irradiation

Knowledge of the chemical stability of active pharmaceutical ingredients (APIs) is an important issue in the drug development process. This work describes a methodical approach and a comprehensive protocol for forced photodegradation studies of solid clopidogrel hydrogen sulfate (Clp) under artificial sunlight and indoor irradiation at different relative humidities (RHs) and atmospheres. The results showed that, at low RHs (up to 21%), this API was relatively resistant to simulated sunlight as well as indoor light. However, at higher RHs (between 52% and 100%), more degradation products were formed, and the degradation rate increased with rising RH. The influence of oxygen on the degradation was relatively low, and most degradation reactions proceeded even in humid argon atmosphere. The photodegradation products (DP) were analyzed with two different HPLC systems (LC-UV, LC-UV-MS) and selected impurities were separated by a semi-preparative HPLC and identified by high resolution mass spectrometry (ESI-TOF-MS) and 1H NMR techniques. Based on the obtained results, a light induced degradation pathway could be proposed for Clp in solid state.

A molecularly imprinted polymerized high internal phase emulsion adsorbent for sensitive chemiluminescence determination of clopidogrel

A molecularly imprinted polymerized high internal phase emulsion (MIP-polyHIPE) adsorbent was used for selective separating and preconcentrating the anti-plaque drug, clopidogrel. For the first time in this study, chemiluminescence (CL) methods were evaluated for the determination of clopidogrel. The synthesis of adsorbents by the emulsion templating method showed that the sensitivity of the method can be increased up to 42 times. The determination of clopidogrel was evaluated by Ru(phen)₃²⁺-Cerium (IV), KMnO₄-H₂SO₄, KMnO₄-H₂SO₄-Na₂SO₃, and luminol-H₂O₂ CL systems. According to the results, only the Ru(phen)₃²⁺-Cerium (IV) CL system showed a reasonable sensitivity for clopidogrel. Using MIP-polyHIPE adsorbent, the linear range, the limit of detection, and relative standard deviation for clopidogrel in this system were respectively 1.0 × 10^-9-8.0 × 10^-8 mol L^-1, 3.0 × 10^-10 mol L^-1, and 6.3% (n = 4, 1.0 × 10^-8). The proposed method was employed for determining clopidogrel in pharmaceuticals and blood serum samples. The results showed the good sensitivity and accuracy of the proposed method.

Analysis of Aspirin, Prasugrel and Clopidogrel in Counterfeit Pharmaceutical and Herbal Products: Plackett–Burman Screening and Box–Behnken Optimization

An isocratic reversed-phase high-performance liquid chromatographic method has been developed and validated for the simultaneous determination of aspirin, prasugrel HCl and clopidogrel bisulfate in the presence of clopidogrel-related compound (impurity-A) in focus on counterfeit. This method was used to determine counterfeited antiplatelet drugs in two substandard Indian pharmaceutical products sold on the market in Yemen and two traditional herbal medicines sold on the market in China. Thin layer chromatography and mass spectrometry of counterfeit herbal medicines have additionally been carried out to verify the identification of adulterants. Chromatographic separation was performed on Inertsil ® ODS-3 C18 (4.6 × 250 mm, 5 μm) with isocratic mobile phase elution containing a mixture of acetonitrile: (25 mM) potassium dihydrogen phosphate buffer, pH 2.7 adjusted with 0.1 M o-phosphoric acid (79: 21, v/v), at a flow rate of 1 mL/min and UV detection at 220 nm. Designs of experiment methodology, Plackett–Burman and Box–Behnken designs were used for the screening and optimization of the mobile phase composition. The method validation was also performed in accordance with the International Council on Harmonization (ICH) guidelines. The method developed for routine analysis was found to be sensitive, simple, accurate and highly robust. The results were statistically compared to reference methods using Student’s t-test and variance ratio F-test at P < 0.05.

Silver nanoparticles impregnated chitosan layered carbon nanotube as sensor interface for electrochemical detection of clopidogrel in-vitro

Continuous periodical monitoring of clopidogrel in physiological body fluids is indispensable in medical diagnosis of heart ailments and cardiovascular diseases. A highly sensitive electrochemical sensor has been fabricated with silver nanoparticles embedded chitosan-carbon nanotube hybrid composite (AgChit-CNT) as sensor interface for detection of the important anti-platelet drug, clopidogrel (CLP). Synthesized AgChit-CNT nanocomposite is examined by x-ray diffraction, Raman spectroscopy and field emission scanning electron microscopy for its chemical and structural characteristics. Crystalline silver nanoparticles of about 35 nm are well distributed in the composite and have formed continuous chain like linkages with CNTs all throughout. Electrochemical responses of the fabricated AgChit-CNT nanocomposite electrode for the determination of CLP have been examined by cyclic voltammetry and electrochemical impedance spectroscopy. The nanoAg patterned CNT nanocomposite interface acts as an excellent electron transfer mediator towards the oxidation of clopidogrel. Electrochemical determination of CLP was investigated by differential pulse voltammetry (DPV) and amperometric analysis under optimized conditions. The limit of detection by DPV and amperometry were 30 nM and 10 nM, respectively, and the time of the analysis is as low as 10 s. Practical applicability for determination in artificially prepared urine and pharmaceutical formulation has been examined with good recovery limits of 95.2 to 102.6%.

A Review of Analytical Methods for the determination of Clopidogrel in Pharmaceuticals and Biological Matrices

P2Y12 belongs to a group of G protein-coupled (GPCR) purinergic receptors and is a receptor for adenosine diphosphate (ADP). The P2Y12 receptor is involved in platelet aggregation and acts as a biological target for treating thromboembolisms and other clotting disorders. The use of Clopidogrel (CLO) has improved the morbidity and mortality endpoints including cardiovascular death, recurrent myocardial infarction (MI) and stroke at 30 days after percutaneous coronary intervention (PCI). CLO is one such drug that specifically and irreversibly inhibits the P2Y12 subtype of ADP receptor. This review delivers a detail description of various analytical methods published for the estimation of CLO and its combinations in pharmaceuticals and biological matrices. The review highlights the basic as well as advanced techniques performed for estimating CLO. The most commonly used assay techniques were UV and Visible spectrophotometry, high performance liquid chromatography (HPLC), high performance thin layer chromatography (HPTLC), micellar liquid chromatography (MLC), micellar electro kinetic chromatography (MEKC) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Despite other analytical methods employed for the assay of CLO, the review reveals that the technique of HPLC with UV detection was widely used.