Support : Publications : Chronolog Archives : Mar/Apr 2003

Pharmaprojects Introduces New Pharmacokinetics Data

The recent reload of Pharmaprojects (File 128/PHAR), the database tracking worldwide pharmaceutical R&D published by PJB Publications Ltd., introduces a new field highlighting the pharmacokinetic data that has been published on a drug. This information looks at the absorption, distribution, metabolism and excretion rate of a drug once it has been administered, including how long it lasts in the body, how much of it is distributed and the maximum concentration which is attained. This kind of information is becoming increasingly important in drug development, as it may affect the way a drug is delivered and how acceptable it will be to patients. For example, a drug whose pharmacokinetic parameters allow it to be taken as a pill once daily is likely to be preferred to one which must be administered by injection four times a day.

Previously this information was presented in the text, but to make it easier to identify and to search, it is now contained in its own field in tabular format. In addition, the amount of pharmacokinetic data held in the file is being increased.

The first part of the table indicates in which species and at what doses the drug was given to generate the subsequent pharmacokinetic values, as they can be species and/or dose dependent. Where available, human data is given (e.g.: Human (5mg po bid)). This means that 5mg of the drug has been administered orally twice a day. Pharmacokinetic studies are carried out in animals such as monkeys, dogs and rodents prior to human testing and these are also reported.

Figures on any or all of the following parameters may be reported:

Bioavailability: This is the fraction of unchanged drug that reaches the systemic circulation and is expressed as a %, usually for an orally-administered drug. Generally, a high bioavailability is desirable, as more of the drug is absorbed and able to take effect. A drug with low bioavailability may be of interest to companies with specialist drug delivery technologies to offer for licensing.

t1/2: This is the drug's half-life, the time it takes for 50% of it to be eliminated from the body. This gives an indication of how long the drug works for and how often it might need to be taken. It is measured in hours. Sometimes this is split into two components, where the t1/2_ is the distribution phase and the t1/2_ is the elimination phase.

Tmax: Time from administration to reach peak blood concentration.

Cmax: The peak plasma concentration achieved following a single dose.

AUC: This is short for area under the curve and is a measure of the total amount of drug to which the patient is exposed following administration.

Vd: This is the volume of distribution or the volume of fluid in the body in which the drug appears to distribute, measured in litres.

Cl: This is a measure of the rate at which the body eliminates the drug.

Here is an example of the pharmacokinetic data for the drug tacrolimus (record no 10364):

Human (5mg po): Bioavailability: 18.00: %
Human (5mg po): t1/2: 34.80: hr
Human (5mg po): Tmax: 1.60: hr
Human (5mg po): Cmax: 29.70: ng/ml
Human (5mg po): AUC: 243.00: nghr/ml
Human (5mg po): Vd: 1.94: l/kg
Human (5mg po): Cl: 0.04: l/hr/kg

It is hoped that this improved presentation and increased coverage of pharmacokinetic data will be of benefit to users on several fronts. First, it adds to the scientific content of each record. Second, it can be used to help make an assessment of the likelihood of a drug reaching the market or its possible market size. Finally, companies involved in drug delivery might find it useful to identify candidates that might benefit from reformulation in their proprietary delivery technologies.

For questions relating to searching Pharmaprojects on Dialog or Dialog DataStar, call the Knowledge Center nearest you. Consult the Dialog Bluesheet and Dialog DataStar Datasheet for Pharmaprojects for further information on the location and the searchability of the pharmacokinetics data.

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