文档介绍：Drug Design
An Introduction to Formulation
J E Newbery
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Objectives
With the possible exception of anaesthetic gases, medicinal substances are delivered to the body as formulated products.
A formulated substance could also be called a dosage form, and consists of an Active Pharmaceutical Ingredient (API) and various excipients.
Dosage Forms
Dosage forms vary from relatively simple mixtures (as in a powder blend or a solution) to plex devices such as patches.
You should insert here some reference to prehensive listing of dosage forms (part of your post-lecture study).
Common features
Despite the wide range of dosage forms there are mon features:
Should be stable – patibility between the API and the excipients
Should be capable of consistent manufacture (quality – adherence to a specification)
Should deliver a consistent effect to the patient
Stability
Dosage forms are mixtures of chemicals – hence they are inherently unstable. The question is not ‘whether the substance will degrade?’ but ‘Can the rate of degradation be controlled?’
Stability is monitored by observing both the reduction in the API content, and the increase of a degradation product.
Control of stability
The dosage form has to be formulated correctly so that the maximum shelf-life is attained.
Degradation occurs through bination of chemical, physical, and microbiological processes. These effects are controlled by correct processing and by selection of suitable excipients.
Quality
Adherence to a specification is the key feature in a quality system. The specification is generated during formulation trials and must reflect average manufacturing conditions.
Formulation work starts on a gram-scale, moves through to kilo-scale and then to 100s of kilos or tonnes.
Technological transfer
As the scale of working is increased from the lab to the pilot plant and then to production scale the processes involved have to be transferred.
There is a wealth of difference between stirring somet