For modified-release dosage forms, appropriate sampling procedures should be followed under suitable test conditions.

Bioavailability studies of a modified-release dosage form in healthy control volunteers may not apply to all circumstances.

However, some modified-release dosage forms of nicotinic acid do cause liver toxicity at a 500 mg dose.

For drugs in modified-release dosage forms, bioequivalence should be demonstrated under both fasting and fed conditions in keeping with current requirements.

• drugs in modified-release dosage forms are those described in the TPD guidance:

The modified-release dosage forms generally produce less of the transient flushing side effect experienced with the immediate-release dosage form.

Drugs in Modified-Release Dosage Forms BE must be demonstrated under both fasted and fed conditions.

The guidances, methodology, and standards given in this document may require modification for certain drugs-for example, those with one or more of the following characteristics: a) b) Modified-release dosage forms.

For drugs in modified-release dosage forms (Guideline B drug products), where the usual requirement is for both fasted and fed studies, requests have been made at times to waive one or the other condition.

Modified-Release Dosage Forms The policy stated in section 1.1 applies to modified-release dosage forms, as defined in Report B of the Expert Advisory Committee:

The respondent raised the following issues: — the scientific basis for different prescription dose limits between immediate-release and modified-release dosage forms, especially concerning liver toxicity; and — concerns about potential adverse effects, such as transient episodes of low blood pressure in the elderly, with the immediate-release 500 mg dose; Response: