All You Need to Know about Immunoassay Drug Test for Drug Development

All You Need to Know about Immunoassay Drug
Test for Drug Development
During drug development, measuring toxicity and impact of the drug
compounds in a product is an essential activity. This is achieved by
developing immunoassays or test systems that analyze the safety and
efficacy of the drug compound. These immunoassays allow testing of drug
interaction with the biochemical, cellular, or molecular processes.
Understanding Immunoassay Drug Test
The immunoassay drug test assesses the immune reaction triggered by
specific antigens and the corresponding protein developed by this response.
These proteins produced due to immune response are called antibodies,
which are utilized to figure out the target compound present in a given
sample.
In a sandwich immunoassay, a target is bound using two different
antibodies. One of these antibodies is attached to a solid plate through
immobilization. The first antibody on the solid plate binds antigen to it and
the second antibody binds to the free side of antigen.
In a competitive immunoassay, only one antibody is utilized to evaluate
antigen presence. This process is utilized when analytes are relatively small
for sandwich immunoassay.
Types of Immunoassay
The importance of the immunoassay drug test is attributed to its high
throughput, sensitivity, and specificity for multiple analytes present in the
biological samples. Owing to these aspects, immunoassay tests are widely
used in drug discovery and development. Below, we have explained
different types of immunoassays that can be utilized during drug
development.

Radioimmunoassay
In radioimmunoassay, the antigen related to the drug development is
attached with a radioisotope and bound to the complementary antibody.
After achieving this, the sample antigen is added to replace the radioactive
antigen. Once the process is completed, the unbound antigens are washed
away and radioactivity is calculated. The sample’s radioactivity is
inversely proportional to the target antigen.
Enzyme-Linked Immunosorbent Assay
In the ELISA immunoassay, an enzyme is connected to the antibody,
which goes through incubation. After incubation is completed, the
unbound antigens are removed or washed so that antibody-enzyme can be
measured. This is achieved by the addition of a substrate to the final
solution. A chemical reaction relevant to the substrate caused by the
enzyme leads to change, which is then used to analyze the target antigen.
Counting Immunoassay
The counting immunoassay process is carried out by coating multiple
antibodies to the polystyrene beads. These antibodies and the target antigen
are complementary to each other. When the polystyrene beads are exposed
to incubation, antigens and beads bind together to form a large mass. The
unbounded beads are calculated through a cell counter. These calculated
unbounded beads are inversely proportional to the antigen.
Chemiluminescence Immunoassay
The chemiluminescence immunoassay is similar to the ELISA
immunoassay. The antibody or antigen is coated over solid particles. After
incubation of these particles, the substrate is added to the solution which

generates light. This intensity of the light is measured as it is directly
proportional to the target antigen.
Fluro Immunoassay
The fluorescent probes are utilized to label the antibodies, which are then
exposed to antigen incubation. After completion of the incubation process,
the intensity of the fluorescent is measured.
Immunoassay tests in Drug Development
Immunoassay tests are widely utilized for drug monitoring,
pharmacokinetic, toxicokinetic, and bioequivalence analysis of drug
development. The type of immunoassay for a particular drug discovery
experiment is decided, based upon various goals of the study. Selecting the
right method is imperative for successful completion of different drug
development phases. Hence, it is very important to assess the requirements
of the experiment before proceeding with any of the above immunoassay
tests.