Formulation is the process by which the raw drug is converted into a form that can be administered to patients (e.g. an ampoule or vial for intravenous, intramuscular, or subcutaneous administration, or a capsule or tablet for oral administration). The route of administration selected must be appropriate for the biological and physico-chemical properties of the compound, and the agent must be shown to be active when given by that route. For example, for intravenous administration, the compound must be soluble in a pharmaceutical^ acceptable solvent at biological pH, whereas for oral administration, the product must be stable in acid. In some cases, it may be necessary to add excipients (other inert materials) to aid solubility, stability, etc. Once a putative formulation has been developed, the stability of the product in the excipients must be confirmed for a minimum of three months (one month for a solution in saline).
Batches of both the raw drug and the final product should be assessed for stability under a variety of environmental conditions for up to three years. These data will be used to attach a shelf life to the product when it is sent to the hospitals for clinical trials. The stability of the compound once reconstituted and compatibility with the giving sets (e.g. stickiness to plastic) should also be investigated so that clear instructions can be provided for the appropriate administration of the drug (e.g. use within two hours of reconstitution, or protect from light).
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