In Vitro & In Vivo Assays

In Vitro Assays

Helping you develop and maintain effective drugs

In vitro assays are used when the particular stage of a target organism (usually a parasite or bacteria) can exist long enough outside a host to assess its susceptibility to treatment. They are also used when a free-living stage is significant enough to merit assay.

We use in vitro assays to:

• Compare the effectiveness of a candidate compound with an existing compound
• Identify the level at which a candidate compound is effective

Although the results cannot be directly extrapolated into the final host animal, in vitro assays are a useful and cost-effective way to screen candidate compounds early.

Efficacy

We can use an in vitro assay, or series of assays, to determine the level of treatment required to kill a particular parasite. We evaluate different concentrations of the treatment to establish the optimum dose.

Resistance

When a parasite develops resistance to treatment, the dose-response curve moves along the X-axis. We use in vitro assays to confirm the presence of and characterise this movement.

In Vivo Assays

In vivo assays are used to conduct preclinical and clinical evaluations of candidate compounds and their formulations. They are carried out in or on the target host animal.

We use in vivo assays on target compounds and formulations to:

• Test their efficacy
• Assess their safety
• Establish and confirm the best dosage

You can use the results of the studies to support your submission to government regulators when your product is ready to be considered for registration and authorisation.

Efficacy

We can assess a treatment’s efficacy on animals carrying a natural infection. We administer the treatment and then compare, for example, the WECs of treated and untreated animals. To test how well a treatment works as a preventative therapy, we can administer it first and then challenge the animals with the parasite. We can also collect adult worms from the animal to assess a treatment’s efficacy.

Resistance

We can test specific species of parasites to see if they’re developing resistance to a particular treatment. We administer the treatment to animals carrying the parasite and examine the number and stages of any remaining parasites after sufficient time for the treatment to fully effect. We then compare this result to that expected when the treatment is administered to susceptible parasites.

Ectoparasites and Endoparasites

How our in vitro assays help you to combat them

In vitro assays help you determine the efficacy of your candidate compound and identify its effective level. They can also confirm that a parasite develops resistance to a particular compound. The tests can simultaneously evaluate the same dose rate or exposure level and different dose rates or exposure levels.

We can carry out in vitro assays on many ectoparasites such as ticks, fleas, lice, mites and various stages of biting or blow flies and many endoparasites including fluke and nematodes.

How our in vivo assays help you combat them

In vivo assays help you determine the efficacy and safety of your candidate compound and identify its effective level. They can also help confirm whether or not a parasite is developing resistance to a particular compound.

We run in vivo assays on animals carrying a natural infestation of many endoparasites including fluke and nematodes and ectoparasites such as:

• Ticks
• Lice
• Mites
• Various stages of biting or blow flies

We can also supply the treatment and then introduce the parasite to test whether the treatment will prevent infestation.