It is important to use the correct amount of topical steroid for your eczema, as instructed by your healthcare professional. Topical steroids should be applied with clean hands so that the skin just glistens. It can sometimes be difficult to judge how much steroid to use and there are guidelines on the amount required to cover body areas that are affected by eczema. These are based on the Finger Tip Unit (FTU), and explained in detail in our fact sheet which you can download as a pdf from the related documents to the right of this page.
In summary, the three bioequivalence approaches that are currently consistently accepted by regulatory authorities are bioequivalence studies with clinical endpoints, in-vivo pharmacodynamic studies (in particular VCA for topical corticosteroid products), and waivers for topical solutions. Also, most require pharmacokinetic studies if there are safety concerns relating to systemic exposure. However, it is refreshing to see that the regulatory authorities are giving credence to alternative science-based methods for demonstration of bioequivalence, rather than insistence on clinical endpoint studies.
Pharmacokinetic studies in men with Topicort® (desoximetasone) Ointment % with tagged desoximetasone showed no detectable level (limit of sensitivity: μg/mL) in 1 subject and and μg/mL in the remaining 2 subjects in the blood when it was applied topically on the back followed by occlusion for 24 hours. The extent of absorption for the ointment was 7% based on radioactivity recovered from urine and feces . Seven days after application, no further radioactivity was detected in urine or feces. Studies with other similarly structured steroids have shown that predominant metabolite reaction occurs through conjugation to form the glucuronide and sulfate ester.