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Glossary

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PD

pharmacodynamics

PDP

product development partnership

pharmacodynamics

A study of the reactions between drugs and living structures. Pharmacodynamics measures the effects that a given drug has on various systems in the body.

pharmacokinetics

The study of what the body does to an administered drug over a period of time. Pharmacokinetic studies measure the absorption, distribution, metabolism, and excretion of a drug.

pharmacology

The study of the origin, chemistry, and uses of drugs and their effects on the body.

Phase I

A closely monitored clinical trial of a product conducted in a small number of healthy volunteers. A Phase I trial is designed to determine the product’s safety in humans, any reactions it may cause within the body and any side effects associated with increasing doses.

Phase II

A controlled clinical study of a product to identify common short-term side effects, risks associated with a product and, in some cases, a first measurement of potential efficacy. Phase II trials enroll volunteers who have the same characteristics as people who would be enrolled in the later Phase III trials. Phase II trials enroll up to several hundred participants and often have a number of different testing “arms,” or groups.

Phase IIb

A controlled clinical study, sometimes known as a “proof-of-concept” trial. These trials provide valuable information on the safety and potential efficacy of an experimental product.

Phase III

A large, controlled study to determine efficacy, or the ability of a product to produce a desired clinical effect (e.g., to prevent HIV). These trials also gather additional information about safety, which is needed to evaluate whether the product should be approved and distributed. Phase III trials usually include several hundred to several thousand volunteers at multiple testing centers.

Phase IV

Post-marketing studies conducted after a new treatment is approved by a government regulatory body. These post-approval trials have several objectives, including comparing the drug with other drugs already in the market, monitoring the drug's long-term safety and effectiveness and determining additional potential uses for the drug.

pilot scale batch

A small-scale batch of a drug product produced in preparation for a full-scale batch. Pilot scale batches help researchers develop techniques that will be required to create much larger batches needed for clinical trials and, later, manufacturing of approved products.

PK

pharmacokinetics

placebo

A substance that looks, smells and feels just like the active drug, but does not have any active ingredients (APIs) in it. In the case of microbicides, the placebo gels, rings or other formulations will look just like the active gels, rings or other formulations, but will not have the active drug substance. Placebos are required in clinical trials to serve as a comparison so that researchers can determine if the investigational product had a statistically-significant effect.

PMTCT

The abbreviation for prevention of mother-to-child transmission of HIV infection, also called “vertical transmission.”

polyanion

Polyanion microbicides attract the positively charged HIV. It was hoped that polyanion-based microbicides would prevent HIV from binding to and entering healthy target cells. To date, no microbicides based on polyanions have been found to be efficacious against HIV.

preclinical research

Before any testing can be done with human volunteers, researchers must first complete a large number of tests in the laboratory (in test tubes) and in animal models. These tests are critical in determining if an experimental product is safe enough to test in humans. IPM is committed to performing only the minimum amount of animal testing necessary to meet safety requirements established by regulatory bodies. Safety information from preclinical trials is used to support an Investigational New Drug (IND) application .

prevalence

The number of people in a population infected with a particular disease at a given time. Prevalence can be thought of as a snapshot of all existing cases at a specified time. (Contrast with incidence, which measures the number of new cases).

product development partnership

A model that brings together private sector technologies and public sector resources. IPM’s PDP model is built on successful collaboration between IPM and a number of parties, including: public and private donors, pharmaceutical companies, scientific research organizations, global policy makers and non-governmental and international organizations.

protocol

The detailed plan for a clinical trial that states all aspects of trial design, including the goals and objectives of the trial, as well as how it will be carried out.