PEPTIDE
Unique Pharmacokinetics Evaluation System for Peptide Drugs
Peptides – a unique class of pharmaceutical compounds composed of a series of well-ordered amino acids usually with molecular weights of 500- 5,000 Da – have become a popular area of drug development. However, due to their structures and properties, peptides pose many challenges to peptide drug development, including low dosage, non-specific adsorption, low stability, high protein binding ratio, poor membrane permeability, complicated metabolic pathways, and a short half-life.
WuXi AppTec’s Drug Metabolism and Pharmacokinetics (DMPK) Service Department has built a well-established druggability evaluation system for peptides based on the team’s experience in peptide research. The system provides a complete solution for DMPK studies of peptides, covering stability and metabolic soft spot research at the screening stage, evaluation of in vivo pharmacokinetics and species selection at the preclinical candidate stage, and radiolabeled ADME experiments at the IND application and clinical trial stage. With extensive experience in strategic research, experimental design, sample analysis, problem solving, and data interpretation, we’re now able to deliver fast, high-quality and effective peptide research services to our partners and ensure smooth project implementation.
We have supported the screening and evaluation of tens of thousands of peptide molecules as well as the IND applications of dozens of peptide molecules. In this process, we have accumulated extensive experience and formed a specific methodology for pharmacokinetic research related to various peptide compounds. We are confident that we can help our clients develop new peptides better and faster.
Peptide Pharmacokinetic Research Services
Absorption
Permeability assessment through in vitro permeation model
Study on absorption through in vivo PK
Formulation screening
Distribution
Plasma protein/albumin binding ratio (ultracentrifugation)
Tissue distribution or QWBA method to study drug distribution
Metabolism
Whole blood/plasma stability
Liver and kidney S9/homogenate stability
Study on metabolic transformation through metabolite identification
Excretion
Study on excretion pathways through in vivo excretion experiments
Drug-drug Interaction (DDI)
(For Peptides with Low Molecular Weight)
Well-established DDI assessment based on drug metabolic enzymes
Well-established DDI assessment based on transporters
Pharmacokinetic Research Content
Challenges in Peptide Pharmacokinetic Studies
High Difficulty
Peptide molecules are physiologically active. Therefore, the dosage is small and the drug concentration in vivo is rather low. Additionally, there are a large number of endogenous interfering substances in organisms. Both the specificity and sensitivity of the analysis method must be high.
Multiple charged ions are likely to be generated in the mass spectrometry ion source by peptide molecules. Also, ions of different valence states are dispersed to a certain extent, making it difficult to determine the optimal ion pair.
Peptide molecules also have some other common problems such as non-specific adsorption, low stability, and a high protein binding ratio, posing serious challenges for sample processing and detection.
Peptides cannot easily cross various bio-membrane barriers in the body as they are highly polarized and poorly permeable. Thus, the oral bioavailability of peptides needs to be improved.
Peptides have poor metabolic stability, wide metabolic pathways, and short half-life periods.
High Significance
Screen out stable peptides, enhance in vivo exposure, and prolong half-life.
Improve the absorption and intracellular concentration by studying the mechanism of permeation and transport of peptides.
Assess the immunogenicity of peptides and determine their impact on PK.
Key Study Capabilities
Comprehensive characterization of metabolic stability and soft spots of peptides.
High-sensitivity quantitative analysis of peptides of various molecular weights and types.
Study on mass balance and tissue distribution of peptides through radiolabeled ADME and QWBA platforms.
Pharmacokinetic Research Strategies for Peptides
Preclinical research on peptides mainly focuses on stability, permeation, delivery carrier, and tissue distribution studies.
Mainly investigating the in vitro properties of peptide molecules (including plasma stability, metabolic stability, permeation and protein binding), and guide molecular structure optimization. The interactions and enzyme phenotyping of peptides with low molecular weight are evaluated as well.
This stage focuses on the metabolic differences of species and the in vivo PK study of peptides. It aims to select the appropriate species for relevant research by considering both pharmacodynamics and toxicology. The study of various delivery carriers makes it possible to achieve the desired in vivo exposure characteristics.
In this stage, single dose escalation and repeated administration PK in animals will be studied. The excretion pathway (mass balance), tissue distribution, and in vivo metabolites identification also need be evaluated.
Our Strengths
Committed to Your Program
We have a specialized and dedicated service model. Each client will be connected to a dedicated study director who will provide comprehensive management services for the pharmacokinetic project from drug discovery to the clinical phase.
Extensive Experience and Short Turn-Around Time
We have more than 10 years of experience on peptide research, with the annual study of 1,000+ peptide molecules, a variety of mature solutions, and a short experiment cycle.
Comprehensive Capabilities and High-Quality Delivery
With an experienced peptide research team and cutting-edge instruments and equipment, WuXi AppTec DMPK is equipped with comprehensive peptide study and analysis capabilities to ensure the delivery of high-quality in vivo and in vitro data.
Customized Study Design
We’re familiar with multiple types of studies and offer customized study design services according to the special properties of a client’s molecules.
Sufficient Research Resources
We have an orderly supply of primate resources to ensure project implementation and shorten the delivery cycle.Case Analysis
Bioanalysis of Exenatide by LC-MS/MS
As a synthetic product of Exendin-4, which is similar to glucagon-like peptide-1 (GLP-1), Exenatide consists of 39 amino acids and is mainly used in the treatment of type II diabetes. In this case, the PK in rats was studied. Since the administration dosage designed in this experiment was quite low, the plasma concentration was predicated to be low accordingly, so the detection sensitivity was required to be high (20 ~ 30 pg/mL). In addition, blood biochemical analysis was also required for this project, leaving a miniscule sample volume for PK detection. This posed a significant challenge to method development.
Using special low-adsorption consumables and reagents, the amount of sample adsorbed by the container was greatly reduced.
As for the non-specific binding or co-precipitation between the sample and protein, the sample was alkalinized to improve the recovery rate.
Solid phase extraction (SPE) was adopted to enrich and purify the plasma sample, which eliminated the endogenous interference and further improved the recovery rate.
The lower limit of quantitation (LLOQ) of this procedure reached ~ 20.9 pg/mL. This result was comparable to that of the RIA procedure reported in the literature.
Low cost (no need to purchase commercial kits)
High throughput (automated workstation for 96-well plates)
Small sample amount (takes only 50-100 µl of a sample, unlike other procedures that require samples to be hundreds of microliters of a sample)
High specificity
Fig. (a). LC-MS spectrum of single blank sample
Fig. (b). LC-MS spectrum of LLOQ (20.9 pg/mL)
[1] Ai G, Zhen Z, Shan C, Che J, Hou Y, and Cheng Y. Single- and multiple-dose pharmacokinetics of exendin-4 in rhesus monkeys. International Journal of Pharmaceutics, 2008, 353:56-64.
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