Drug delivery

As well as making a drug, a pharmaceutical company has to turn it into a usable product.

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

All drugs contain, in addition to an active ingredient, other compounds that contribute to its 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. Other constituents help it to dissolve, mask a bitter taste or help it disperse around the body. Generally, the composition of the pill is finalised by the time phase III trials are run.

Other possible routes of administration include suspensions, nasal sprays (as with Ventolin for asthma) and rectal suppository. The latter might be used for local effects (haemorrhoid treatment, for example) 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.