Pivotal Bioequivalence Study of Clopacin®, a Generic Formulation of Clopidogrel 75 mg Film-Coated Tablets.

INTRODUCTION: Clopacin(®) (Acino Pharma AG) is a proprietary, besylate salt and lactose-free formulation of the widely-used anti-platelet treatment, clopidogrel. This study aimed to evaluate the bioequivalence of Clopacin(®) with the originator as reference drug, using a guideline-compliant trial design: open-labeled, randomized, single-dose (clopidogrel 75 mg tablet), two-period, crossover trial in 48 healthy male volunteers, with a 7 day wash-out period. METHODS: Plasma samples were collected at intervals and extracted before quantifying clopidogrel concentrations using a fully validated LC-MS/MS method. Bioequivalence of Clopacin(®) and the reference drug was established by comparison of the primary pharmacokinetic parameters, C max, AUC0-t, and AUC0-∞. RESULTS: The parameter values were similar for the two products (analysis of variance) and provided Clopacin/reference ratios (least squares means) of >90% and 90% confidence intervals (CIs 84.64-105.50%, 90.43-111.22%, 88.75-110.71%, respectively) that were well within the limits set for defining bioequivalence, according to international guidelines. The respective Clopacin(®) and reference drug values for mean time to maximal plasma clopidogrel concentration (t max) were 0.83 and 0.91 h, and for terminal elimination half-life were 3.99 and 3.51 h. The intra-subject coefficients of variability for maximal plasma clopidogrel concentration (C max), area under the plasma clopidogrel concentration versus time curve, at 48 h (AUC0-t) and extrapolated to infinity (AUC0-∞) were 32.2%, 30.2%, and 28.9% (least square means), respectively, and the respective power values were 99.5%, 97.1%, and 95.3%. CONCLUSION: This bioequivalence study provided robust clopidogrel pharmacokinetic data that established the bioequivalence of Clopacin(®) and the reference originator drug. FUNDING: Acino Pharma AG (formerly Cimex AG).

Antioxidant therapy in critical care--is the microcirculation the primary target?

This review presents the rationale for the therapeutic use of antioxidants in treating critically ill patients; it is not a systematic review of the clinical evidence that has been assessed recently by others. Clinical and nonclinical evidence is presented to support the notion that natural antioxidants are of therapeutic value in treating cardiovascular shock. Oxidative stress is a major promoter and mediator of the systemic inflammatory response. The microcirculation is particularly susceptible to oxidative stress that causes hemodynamic instability, leading to multiple organ failure due to systemic inflammatory response syndrome. Vitamin C is the antioxidant used experimentally to demonstrate oxidative stress as a key pathophysiologic factor in septic shock. Pharmacologic studies reveal that vitamin C (as ascorbate), at supraphysiologic doses, significantly affects the bioavailability of nitric oxide during acute inflammation, including inhibiting nitric oxide synthetase induction. Parenteral high-dose vitamin C inhibits endotoxin-induced endothelial dysfunction and vasohyporeactivity in humans and reverses sepsis-induced suppression of microcirculatory control in rodents. In severe burn injury, in both animals and patients, parenteral high-dose vitamin C significantly reduces resuscitation fluid volumes. Therefore, a significant body of pharmacologic evidence and sound preliminary clinical evidence supports the biological feasibility of using the exemplary antioxidant, vitamin C, in the treatment of the critically ill.

Calcitonin receptor-like receptor: identification and distribution in human peripheral tissues.

We report here on the characterization and immunohistochemical localization in human tissues of calcitonin receptor-like receptor (CRLR) which was recently found to mediate the effects of both calcitonin gene-related peptide (CGRP) and adrenomedullin (ADM). Western blot analysis using antibodies raised against the first extracellular loop and the carboxy-terminal part of hCRLR, respectively, detected two major bands corresponding to about 70 and 60 kDa in membrane preparations of cultured endothelial cells and numerous organs including lung, heart ventricle and kidney. Immunohistochemical analysis of the cardiovascular system revealed CRLR-like immunoreactivity (CRLR-LI) in the endothelium of all blood vessels including large and small arteries, veins and capillaries, and in heart muscle cells and endocardium. The lung showed intense staining over the alveolar capillaries. Within the digestive tract, staining was observed over the cells lining the excretory ducts of the parotid gland, over the epithelium of the fundic glands of stomach, endocrine cells of the duodenum and ileum and some myenteric ganglia. The kidney presented staining of the juxtaglomerular arteries, the glomerular capillaries and chief cells of the collecting duct. Within the endocrine organs, a strong CRLR-LI signal was observed over the Langerhans islets, and weak immunoreactivity in the Leydig cells of testis. Spleen showed intense staining in trabecular veins and sinuses. Macrophages displayed a variable immunoreactivity. Our data demonstrate a wide distribution of CRLR throughout the human body and suggest CRLR to be involved in the mediation of a variety of actions in addition to vascular control.

Calcitonin receptor-like receptor is expressed on gastrointestinal immune cells.

BACKGROUND/AIMS: Pharmacological and morphological studies suggest that the gut mucosal immune system and local neuropeptide-containing neurones interact. We aimed to determine whether gut immune cells are targets for calcitonin gene-related peptide (CGRP), which has potent immune regulatory properties. METHODS: Using density gradient centrifugation, rat lamina propria mononuclear cells (LP-MNCs) and intra-epithelial lymphocytes (IELs) were isolated. RT-PCR was employed for the detection of mRNA of rat calcitonin receptor-like receptor (CRLR), which is considered to represent the pharmacologically defined CGRP receptor-1 subtype, as well as mRNA of the receptor activity-modifying proteins, which are essential for CRLR function and determine ligand specificity. A radioreceptor assay was employed for the detection of specific CGRP binding sites. RESULTS: RT-PCR and DNA sequencing showed that LP-MNCs and IELs express CRLR. Incubation of isolated LP-MNCs with radiolabelled alphaCGRP revealed the existence of specific binding sites for CGRP. CONCLUSION: These novel data indicate that mucosal immune cells of the rat gut are a target for CGRP and provide significant evidence that CGRP functions as an immune regulator in the gut mucosa.