When given by most routes (excluding iv), a drug must traverse several semipermeable cell membranes before reaching the systemic circulation.
采用大多数给药途径给药(静脉注射除外)的药物在进入体循环之前必须通过数层半渗透性细胞膜。
2
Sometimes a phase iv (post-approval) trial is also pursued, where the long-term effects of the drug are monitored on those receiving prescriptions.
有时还有第四阶段，这期间药物的长期效果在接受药物的病人中被监测。
3
In its draft, "Prescription Drug User Fee Act (PDUFA) ivDrug Safety Five-Year Plan," the agency says it will focus on hiring the staff through fiscal year 2009.