4 Ds in health research-working together toward rapid precision medicine.

Patient therapy is based mainly on a combination of diagnosis, suitable monitoring or support devices and drug treatment and is usually employed for a pre-existing disease condition. Therapy remains predominantly symptom-based, although it is increasingly clear that individual treatment is possible and beneficial. However, reasonable precision medicine can only be realized with the coordinated use of diagnostics, devices and drugs in combination with extensive databases (4Ds), an approach that has not yet found sufficient implementation. The practical combination of 4Ds in health care is progressing, but several obstacles still hamper their extended use in precision medicine.

An integrated early formulation strategy--from hit evaluation to preclinical candidate profiling.

The selection of a suitable vehicle for preclinical compound profiling is a very important task during the early developmental phases to ensure the quality of candidates and the speed of compound progression. Apart from biopharmaceutical and pharmaceutical technical considerations, i.e. solubility/dissolution improvement or route of application, other aspects have to be taken into account, as well: (i) availability and quality of the compound, (ii) tolerability of the vehicle in the selected animal model, (iii) developmental possibilities, i.e. whether the formulation can be transformed into a clinical one. The approach described in this paper is based on results of team collaboration between functions involved in the conduct of animal experiments (Pharmacology, Pharmacokinetics, Toxicology, and Pharmaceutical Sciences). Very early in vivo studies should be performed with dissolved API as available information on solid-state characteristics is usually limited at this time. Later studies should be performed with developable formulations, taking into consideration pharmacological, toxicological, and pharmaceutical requirements. At this stage, delivery strategies (i.e. advanced formulations and/or alternative routes of administration) should be considered, as well. In addition, a minimum level analytical characterization of compounds and formulations used in animal studies is required to explain unexpected results.

Direct and rapid inhibition of factor Xa by otamixaban: a pharmacokinetic and pharmacodynamic investigation in patients with coronary artery disease.

BACKGROUND: New anticoagulants that combine effective anticoagulation with low bleeding rates are still sought after. We investigated the safety, pharmacokinetics, and pharmacodynamics of otamixaban, a direct factor Xa inhibitor, in patients with stable coronary artery disease. METHODS: This was a randomized, placebo-controlled, double-blind, multicenter study in 119 patients with stable coronary artery disease taking maintenance doses of their comedication. Of these patients, 50% had mild renal impairment (creatinine clearance >45 mL/min but <80 mL/min). Patients were randomized in a 4:1 ratio to receive either otamixaban or placebo as a 1-minute bolus followed by a 24-hour continuous infusion. Anti-factor Xa activity, clotting times (activated partial thromboplastin time, dilute prothrombin time, Russell's viper venom test), and international normalized ratio were measured. RESULTS: All patients completed the study according to the protocol. No major or minor bleeding occurred according to Thrombosis in Myocardial Infarction criteria. Anti-factor Xa activity and anticoagulant effect were measurable early after the start of the infusion and remained during the infusion. Upon cessation, these effects declined rapidly and returned to baseline within 6 hours after the end of infusion. Anti-factor Xa activity coincided with the otamixaban plasma concentrations. The fold changes from baseline at the end of infusion with regard to the clotting times ranged from 1.7 to 4.4 (1.15 for placebo), 1.29 to 3.15 (0.98 for placebo), and 1.19 to 2.11 (0.94 for placebo) for Russell's viper venom test, dilute prothrombin time, and activated partial thromboplastin time, respectively, and ranged from 0.94 to 1.70 (0.94 for placebo) for the international normalized ratio. CONCLUSION: In patients with stable coronary artery disease taking maintenance doses of their usual concomitant medication, otamixaban exerts a rapid onset of anticoagulation and anti-factor Xa activity. Our data provide evidence that further studies are warranted to investigate the safety and efficacy of otamixaban in the target population.

New hepatocyte in vitro systems for drug metabolism: metabolic capacity and recommendations for application in basic research and drug development, standard operation procedures.

Primary hepatocytes represent a well-accepted in vitro cell culture system for studies of drug metabolism, enzyme induction, transplantation, viral hepatitis, and hepatocyte regeneration. Recently, a multicentric research program has been initiated to optimize and standardize new in vitro systems with hepatocytes. In this article, we discuss five of these in vitro systems: hepatocytes in suspension, perifusion culture systems, liver slices, co-culture systems of hepatocytes with intestinal bacteria, and 96-well plate bioreactors. From a technical point of view, freshly isolated or cryopreserved hepatocytes in suspension represent a readily available and easy-to-handle in vitro system that can be used to characterize the metabolism of test substances. Hepatocytes in suspension correctly predict interspecies differences in drug metabolism, which is demonstrated with pantoprazole and propafenone. A limitation of the hepatocyte suspensions is the length of the incubation period, which should not exceed 4hr. This incubation period is sufficiently long to determine the metabolic stability and to allow identification of the main metabolites of a test substance, but may be too short to allow generation of some minor, particularly phase II metabolites, that contribute less than 3% to total metabolism. To achieve longer incubation periods, hepatocyte culture systems or bioreactors are used. In this research program, two bioreactor systems have been optimized: the perifusion culture system and 96-well plate bioreactors. The perifusion culture system consists of collagen-coated slides allowing the continuous superfusion of a hepatocyte monolayer with culture medium as well as establishment of a constant atmosphere of 13% oxygen, 82% nitrogen, and 5% CO2. This system is stable for at least 2 weeks and guarantees a remarkable sensitivity to enzyme induction, even if weak inducers are tested. A particular advantage of this systemis that the same bioreactor can be perfused with different concentrations of a test substance in a sequential manner. The 96-well plate bioreactor runs 96 modules in parallel for pharmacokinetic testing under aerobic culture conditions. This system combines the advantages of a three-dimensional culture system in collagen gel, controlled oxygen supply, and constant culture medium conditions, with the possibility of high throughput and automatization. A newly developed co-culture system of hepatocytes with intestinal bacteria offers the possibility to study the metabolic interaction between liver and intestinal microflora. It consists of two chambers separated by a permeable polycarbonate membrane, where hepatocytes are cultured under aerobic and intestinal bacteria in anaerobic conditions. Test substances are added to the aerobic side to allow their initial metabolism by the hepatocytes, followed by the metabolism by intestinal bacteria at the anaerobic side. Precision-cut slices represent an alternative to isolated hepatocytes and have been used fo the investigation of hepatic metabolism, hepatotoxicity, and enzyme induction. A specific advantage of liver slices is the possibility to study toxic effects on hepatocytes that are mediated or modified by nonparenchymal cells (e.g., by cytokine release from Kupffer cells) because the physiological liver microarchitecture is maintained in cultured slices. For all these in vitro systems, a prevalidation has been performed using standard assays for phase I and II enzymes. Representative results with test substances and recommendations for application of these in vitro systems, as well as standard operation procedures are given.

Prolonged blood glucose reduction in mrp-2 deficient rats (GY/TR(-)) by the glucose-6-phosphate translocase inhibitor S 3025.

Chlorogenic acid derivatives are potent inhibitors of hepatic glucose production by inhibition of the glucose-6-phosphate translocase component of the hepatic glucose-6-phosphatase system. The pharmacological proof of concept was clearly demonstrated during i.v. infusion of potent derivatives (S 4048, S 3483) in rats. However, the blood glucose lowering effect of S 4048 after bolus i.v. injection lasted only 60-90 min. Plasma clearance of S 4048 was very high, and the parent compound was rapidly and efficiently excreted into the bile of Wistar and GY/TR(-) rats, indicating that mrp-2 was not involved in this hepatobiliary elimination process. About 72% of the total administered radioactivity appeared in the bile within 20 min after i.v. bolus injection of the radiolabeled analogue [(3)H]S 1743 in a Wistar rat. However, in GY/TR(-) rats the dicarboxylic analogue of S 4048, S 3025, was cleared from the plasma less rapidly than its parent compound and its biliary elimination was comparatively low. In contrast, S 3025 exhibited comparable pharmacokinetics and biliary elimination profile as S 4048 in Wistar rats, suggesting that biliary elimination of S 3025 is facilitated by mrp-2, functionally absent in GY/TR(-) rats. Targeting to mrp-2 resulted in a significantly prolonged reduction of blood glucose levels in GY/TR(-) rats after i.v. bolus administration of S 3025.