preparationIllicit herbal dietary supplements received for PDE-5 screeningwere either tablets or capsules. The powdered tablets, or the con-tent of the capsules were subjected to analysis. For each sample, aquantity equivalent to the average dosage unit was agitated withmobile phase B for 30 min at a rate of 300 rpm, sonicated for 5 minand centrifuged for 10 min applying 2400 × g. An aliquot of the clearsupernatant was diluted 25-fold with mobile phase B.