When choosing the best drug delivery system for a patient, doctors take a number of factors into consideration, both of the disease and the patient. The symptoms, severity and expected time to recovery of the disease are some factors considered. When choosing the best drug delivery system for a specific patient, the doctor will consider his or her age, clinical condition, lifestyle and, in most cases, other medications.
There are a wide range of different drug delivery systems available and the pharmaceutical industry is always working on developing newer, more patient-friendly systems. A drug delivery system that suits one patient may not suit the next. They are, therefore, chosen carefully and changed, if necessary, as clinical and physical conditions change.
The most common pharmaceutical dosage forms are oral, e.g. tablets, capsules and solutions, suspensions or syrups; rectal, e.g. suppositories; topical, e.g. patches, creams, ointments and sprays and injectables, e.g. intramuscular, intravascular or subcutaneous injections. Within each of these pharmaceutical dosage forms are various drug delivery system forms.
Tablets, for example, may come as enteric-coated. This means that they have a film around them which will dissolve only at a specific pH, or acid level, which is found only at a certain part of the gastrointestinal tract, allowing delivery of the drug to a specific part of the body. Some tablets and capsules may be timed-release or slow-release, allowing the drug to be released over a long period of time. This can be helpful in encouraging adherence, as it allows for once-daily dosing as opposed to twice- or three-times daily dosing.
Topical preparations, may also differ in drug delivery system, allowing release over an extended period of time. Products such as hormone replacement therapy patches work on this principle, allowing changing of the patches on a weekly or monthly basis. Some analgesic preparations work on this drug delivery system too.
Another useful drug delivery system which is often used in patients with chronic pain, such as terminal cancer patients and in the acute setting after surgery, is patient-controlled analgesia. This is a system whereby there is a small pump that allows the patient to administer a dose of the drug to themselves if they feel pain returning. It has been found to be very effective in reducing the anxiety associated with pain and a reliance on administration of analgesia by a third party.
More simply, the choice of the best drug delivery system by the doctor will take basic factors into account. Children, for example, struggle to swallow pills, so a syrup will be prescribed. Patients who are critically ill and can't swallow can be given injectable or rectal preparations. Different drug delivery systems help to ensure that each patient receives the best possible treatment, regardless of their condition.