Haemodynamic Assessment in Safety Pharmacology

Drug-induced blood pressure increase - recommendations for assessment in clinical and non-clinical studies

INTRODUCTION

Changes in blood pressure (BP) are now proactively examined throughout the drug development process as an integral aspect of safety monitoring. This is because hypertension is a very strong risk factor for cardiovascular events and drug-induced increases in BP have attracted increased regulatory attention. However, there is currently no guidance from regulatory agencies on the minimum BP data required for submissions, and there are no specific criteria for what constitutes a safety signal for increased BP in non clinical studies. Areas covered: Evaluation of BP increases through the drug discovery and development process. Expert opinion: Research into the effects of drugs should begin before clinical development is initiated and continue throughout the clinical trial program. Non clinical studies should inform a benefit-risk analysis that will aid decision-making of whether to enter the drug into Phase I development. The degree of acceptable risk will vary according to the therapy area, treatment indication and intended population for the new drug, and the approach to BP assessment and risk mitigation should be tailored accordingly. However, BP monitoring should always be included in clinical trials, and data collected from multiple studies, to convincingly prove or refute a suspicion of BP effects.

Physical Properties and Effect in a Battery of Safety Pharmacology Models for Three Structurally Distinct Enteric Polymers Employed as Spray-Dried Dispersion Carriers

Establishing a wide therapeutic index (TI) for pre-clinical safety is important during lead optimization (LO) in research, prior to clinical development, although is often limited by a molecules physiochemical characteristics. Recent advances in the application of the innovative vibrating mesh spray-drying technology to prepare amorphous solid dispersions may offer an opportunity to achieve high plasma concentrations of poorly soluble NCEs to enable testing and establishment of a wide TI in safety pharmacology studies. While some of the amorphous solid dispersion carriers are generally recognized as safe for clinical use, whether they are sufficiently benign to enable in vivo pharmacology studies has not been sufficiently demonstrated. Thus, the physical properties, and effect in a battery of in vivo safety pharmacology models, were assessed in three classes of polymers employed as spray-dried dispersion carriers. The polymers (HPMC-AS, Eudragit, PVAP) displayed low affinity with acetone/methanol, suitable for solvent-based spray drying. The water sorption of the polymers was moderate, and the degree of hysteresis of HPMC-AS was smaller than Eudragit and PVAP indicating the intermolecular interaction of water-cellulose molecules is weaker than water-acrylate or water-polyvinyl molecules. The polymer particles were well-suspended without aggregation with a mean particle size less than 3 μm in an aqueous vehicle. When tested in conscious Wistar Han rats in safety pharmacology models (n = 6–8/dose/polymer) investigating effects on CNS, gastrointestinal, and cardiovascular function, no liabilities were identified at any dose tested (30–300 mg/kg PO, suspension). In brief, the polymers had no effect in a modified Irwin test that included observational and evoked endpoints related to stereotypies, excitation, sedation, pain/anesthesia, autonomic balance, reflexes, and others. No effect of the polymers on gastric emptying or intestinal transit was observed when measured using a barium sulfate tracer material. Finally, in telemetry-instrumented rats the polymers had no effect on acute or 24-h mean blood pressure and heart rate values at doses up to 300 mg/kg. Thus, the properties of the three enteric polymers are appropriate as spray-dried dispersion carriers and were benign in a battery of safety pharmacology studies, demonstrating their applicability to enable in vivo safety pharmacology profiling of poorly soluble molecules during LO.