Preformulation stage salt form

At an early stage during the preformulation program for the candidate, particularly for those with unfavorable physicochemical and physicomechanical properties as a free acid or free base, it is normal procedure to investigate a suitable range of potential salts. Typically 4-6 different salts are evaluated, if they can be isolated. Often the properties of the free acid (or free base) are hardly satisfactory and it is recommended that it is included in the comparative exercise using a battery of tests (see Section V). If a parenteral dosage form is intended and the properties of the free acid or free base are better than any of the salts, it is often possible to prepare a salt in situ in the liquid vehicle. 

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