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IN VITRO ADMET

To address the challenges encountered within drug discovery and development, Pharmidex offers an extensive suite of absorption, distribution, metabolism, excretion and toxicity/pharmacokinetic (ADMET) in vitro assay solutions.


Pharmidex provides high-quality assay services for lead optimisation and drug development by offering both general and human in vitro assays.


We conduct a broad range of assays (CYP450 interaction, metabolic stability, drug transport, physicochemical properties and others) for generating an overall picture of the in vitro analysis.

Areas of Expertise

Binding Assays

Plasma & Blood Protein Binding Assay


  • Compounds may bind to plasma proteins so only a small fraction of the drug is free in the plasma
  • Rapid equilibrium dialysis
  • Cross-species plasma protein binding
  • Results reported as % bound and fraction unbound (fu)


Cell Culture Media Binding Assays


  • Compounds may bind to serum proteins in cell culture media so that only a small fraction of the drug is actually free in the media
  • Rapid equilibrium dialysis
  • A diverse selection of media available
  • Results reported as % bound and fraction unbound (fu)


Brain Tissue Binding Assays


  • Compounds may bind to brain proteins and lipids so only a small fraction of the drug is free in the plasma
  • Different to plasma protein binding as plasma has twice as much protein and brain has 20-fold more lipids
  • Rapid equilibrium dialysis method
  • Cross-species brain tissue binding
  • Results reported as % bound and fraction unbound (fu)

 

Tissue Binding Assays


  • Compounds may bind to tissue proteins and lipids so only a small fraction of the drug is free in the plasma
  • Rapid equilibrium dialysis method
  • A wide range of tissues and organs available
  • Cross-species tissue binding
  • Results reported as % bound and fraction unbound (fu)

Biological Stability Assays

Plasma & Blood Stability Assay


  • Interpreting discrepancies in blood clinical samples and from in vivo pharmacokinetic studies
  • Cross-species blood stability


Brain & Tissue Stability Assays


  • Certain molecules will be unstable in tissues; this is mainly due to enzymatic processes
  • Interpreting discrepancies in clinical samples and from in vivo pharmacokinetic studies
  • Brain stability assay


Urine Stability Assays


  • Certain molecules will be unstable in urine; this is mainly due to enzymatic processes
  • Acids, antioxidants or preservatives can be added to the urine samples. Prevents compound degradation in alkaline pH urine
  • Interpreting discrepancies in clinical samples and from in vivo pharmacokinetic studies
  • Cross-species urine stability assay


Gastric & Intestinal Juice Stability Assays


  • For orally administered drugs, the stability in gastric and intestinal fluid is an important consideration
  • Using an artificial gastric fluid and intestinal recipe

Physicochemical Properties

Thermodynamic Solubility Assays


  • Thermodynamic solubility tests evaluate the solubility of solid crystalline material in aqueous solvent as a saturated solution in equilibrium
  • Thermodynamic aqueous solubility tests can be performed in any media or buffer


Kinetic Solubility Assays


  • Aqueous kinetic solubility tests evaluate the solubility of a compound already fully dissolved in an organic solvent
  • Kinetic solubility tests can be performed in any media or buffer


Fasted State Simulated Gastric Fluid (FaSSGF) pH 1.6 Solubility


  • Solubility assay performed in artificial FaSSGF
  • This biologically relevant fluid mimics gastric juices because it contains natural surfactants (salts and acids)


Fasted (FaSSIF) and Fed State Simulated Intestinal Fluid (FeSSIF) pH 6.5 Solubility Assays


  • Solubility assay performed in artificial FaSSIF/FeSSIF
  • This biologically relevant fluid mimics intestinal juice because it contains natural surfactants (bile salts and lecithin)


Partition Coefficient (Log D) Assays


  • Log D coefficient is the ratio of concentrations of a compound in the two phases of a mixture of two immiscible solvents at equilibrium
  • This method involves dissolving the compound in a known volume of octanol (hydrophobic) and water or PBS (hydrophilic)
  • Shake-flask method

Metabolic Stability Assays

Microsomal Metabolic Stability Assay


  • Containing metabolising enzymes for phase 1 (oxidation) metabolic processes
  • Cross-species metabolic stability
  • Metabolite identification


Hepatocyte, S9 & Cytosol Metabolic Stability Assays


  • Containing metabolising enzymes for phase 1 (oxidation) and phase 2 (conjugation) metabolic processes
  • Cross-species metabolic stability
  • Metabolite identification

CYP450 Interaction

CYP450 Inhibition Assays


  • Microsomes with recombinant baculovirus containing cDNA for individual human cytochrome P450 (CYP450) enzymes
  • Major CYP450 isozymes: 1A2, 2C9, 2C19, 2D6, 3A4


CYP450 Phenotyping Assays


  • To determine the actual cytochrome P450 (CYP450) responsible for the metabolism
  • Cross-species phenotyping assay
  • Metabolite identification

Metabolite Identification

Metabolite Identification From Metabolism Stability Assays


  • Microsomal stability assays
  • Hepatocyte, S9 & cytosol metabolic stability assay
  • CYP450 phenotyping assay


Metabolite Identification From Chemical/Biological Stability Assays


  • Phosphate Buffered Saline (PBS) stability assay
  • Plasma, blood, gastric juice, intestinal juice, brain, tissue & urine stability assay

Chemical Stability Assays

Phosphate Buffered Saline (PBS) and other Stability Assays


  • To understand any compound stability issues
  • Aqueous stability tests can be performed in PBS and in any media or any other buffer

In vitro Cellular Toxicity Assays

Cellular Toxicity Assay


  • In vitro cell culture techniques can be used to assess the harmful effects of compounds and biomaterials.
  • They represent an ideal living biological system in which toxicity can be evaluated
  • Incubation in cell culture medium, followed by assessment of damage using an appropriate end-point biomarker such as MTT

Drug Transport

MDR1-MDCK & Caco-2 Permeability Assays


  • Mono or bi-directional transport
  • Apical-to-basolateral permeability
  • Basolateral to apical permeability
  • Papp values
  • Transporter inhibition assays

Other Assays

Haemolysis Assays

  • Assessing the potential of compounds, medical devices and other such materials to cause haemolysis.
  • Haemolysis is the breaking of red blood cells (erythrocytes) and the release of their contents into surrounding fluid
  • Evaluating the haemoglobin release in the plasma (as an indicator of red blood cell lysis), following test agent exposure
  • Cross-species

 

Red Blood Cell Partitioning Assays

  • Some drugs have a significantly higher affinity for red blood cells than for plasma
  • Calculation of RBC/plasma ratio
  • Useful for interpreting discrepancies in clinical samples and from in vivo pharmacokinetic studies
  • Cross-species

Free Radical Damage Assays

  • Free radical accumulation in the body generates oxidative stress and cell damage
  • Assessment of the compounds to induce lipid peroxidation
  • Assessment of the compounds to inhibit known lipid peroxidation-causing agents

Biomarker Assays

  • Bespoke or established assays for biomarkers with ELISA and Luminex technology
  • Samples from pharmacokinetic or clinical studies 
  • Enzyme, hormone, cytokines, peptide, receptor or other biomarkers
  • Useful for end-point analysis in clinical and non-clinical studies
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