Abstract
So called 'inert' ingredients are commonly incorporated in topical preparations for various purposes, e.g., to improve consistency, appearance, physical stability and spreadability. Such 'inert' ingredients have often been shown to alter the availability of active ingredients in tablets and capsules. This paper reports the lack of effect of 3 solid inert ingredients commonly used in topical preparations (starch, zinc oxide and calamine) on the percutaneous absorption of methyl nicotinate as assessed by the production of vasodilation.