Drug delivery

It can sometimes be challenging to develop ways to administer drugs

In parallel with research on the medical properties of a potential drug, a company has to ensure it can be given to a patient in a suitable form.

In addition to an active ingredient, all drugs contain other compounds that contribute to their stable delivery. Part of the drug testing process is to ensure that these compounds do not adversely affect the drug in the body.

Pills also include bulking agents – generally, only around 5–10 per cent of a pill will be the active pharmaceutical compound. Its other constituents help it to dissolve, mask a bitter taste or help it disperse around the body. The composition of the pill is usually finalised by the time phase III trials are run.

Other possible routes of administration include suspensions, nasal sprays (e.g. albuterol for asthma), patches and rectal suppository. The latter might be used for local effects (e.g. haemorrhoid treatment) or because patients are having convulsions or vomiting.

Companies thus face enormous practical challenges to get their exciting new drug into a form that can be given to the patient.

Lead image:

e-Magine Art/Flickr CC BY

About this resource

This resource was first published in ‘Drug Development’ in January 2008 and reviewed and updated in August 2014.

Drug Development
Education levels:
16–19, Continuing professional development