After entering systemic circulation, a drug distributes across tissues and organs in a process determined by plasma protein binding, lipophilicity, tissue partitioning, and active transport at biological barriers. The volume of distribution (Vd) and tissue-to-plasma concentration ratios define both efficacy and toxicity profiles.
Our Distribution portfolio delivers validated plasma and tissue binding reagents, blood–brain barrier models, red blood cell partitioning assays, and multi-species tissue homogenate preparations to support comprehensive in vitro distribution characterisation.
Distribution governs where a drug resides within the body after entering systemic circulation. The extent and rate of tissue uptake are shaped by three interacting factors: the unbound fraction in plasma (fu,p), which determines the concentration available for partitioning; tissue affinity driven by lipophilicity, ionisation state, and specific binding interactions; and active transport across barrier epithelia such as the blood–brain barrier and placenta.
Accurate in vitro distribution data reduces reliance on animal studies and enables early prediction of the volume of distribution, tissue accumulation risk, and CNS penetration. Our portfolio encompasses equilibrium dialysis and rapid equilibrium dialysis (RED) formats for plasma protein binding, multi-species tissue homogenates for non-specific tissue binding, and validated cell-based BBB permeability models for CNS distribution assessment.
The plasma unbound fraction (fu,p) is a fundamental parameter in pharmacokinetic prediction, determining the free drug concentration available for distribution and elimination. Equilibrium dialysis and rapid equilibrium dialysis (RED) formats provide the gold-standard measurement approach across preclinical species.
Non-specific tissue binding (fu,tissue) determines the extent to which a drug partitions into organs beyond the plasma compartment. Tissue homogenates provide a rapid, miniaturised in vitro measurement format compatible with equilibrium dialysis and ultracentrifugation methodologies.
Central nervous system distribution is governed by the blood–brain barrier (BBB), a specialised endothelial structure with tight junctions and high transporter expression that severely restricts passive permeation. In vitro BBB models stratify CNS penetration risk and support mechanistic investigation of P-gp and BCRP-mediated efflux at the BBB.
Red blood cell (RBC) partitioning determines the blood-to-plasma concentration ratio (RB/P), a critical parameter for converting in vitro plasma clearance data to whole-blood-based predictions and for interpreting haematotoxicity signals. Accurate RB/P measurement requires matched whole blood and plasma from the same species and anticoagulant condition.
Our dedicated Distribution brand portfolio is currently in preparation. Proprietary reagent lines covering validated plasma protein binding systems, tissue distribution toolkits, and BBB model reagents will be introduced in this section upon launch.
In Development — Check Back SoonThe product catalogue below is ready to receive SKU data. Use the filter chips to browse by dimension. Each product entry carries a catalogue number, product name, category classification, species applicability, format, and a datasheet link.