Christodoulides M, Boucher D W
Blood Products Division, Bureau of Biologics, Ottawa, Ontario, Canada.
Biologicals. 1990 Apr;18(2):103-11. doi: 10.1016/1045-1056(90)90019-v.
An assessment was made of two methods for determining the potency of tissue-type plasminogen activator (TPA). A chromogenic microtitre plate assay was established which contained TPA, plasminogen, a synthetic plasmin substrate (H-D-valyl-L-leucyl-L-lysyl-p-nitroaniline dihydrochloride, S2251) and any one of the following stimulators: native fibrinogen, enzymatic and chemical digests of fibrinogen, poly-D-lysine (PDL) and chemical derivatives of the latter. The chromogen assay was compared with an automated clot-lysis (turbidimetric) assay for sensitivity, reproducibility and validity for potency determination. Reference preparations of TPA were titrated in both assays: in the chromogen assay the dose-response curves were non-parallel, whereas parallelism was observed in the clot-lysis assay. Thus, the chromogen assay was restricted in its applicability and disqualified from any routine regulatory use. The potency of individual lots of recombinant (r)TPA could only be estimated in International Units (IU) of TPA activity with the automated clot-lysis assay and the potency values obtained (IU/vial) were in remarkably close agreement with the manufacturers' values.
对两种测定组织型纤溶酶原激活剂（TPA）效价的方法进行了评估。建立了一种显色微量滴定板测定法，该方法包含TPA、纤溶酶原、一种合成纤溶酶底物（H-D-缬氨酰-L-亮氨酰-L-赖氨酸-对硝基苯胺二盐酸盐，S2251）以及以下任何一种刺激物：天然纤维蛋白原、纤维蛋白原的酶解和化学消化产物、聚-D-赖氨酸（PDL）及其化学衍生物。将显色测定法与自动凝块溶解（比浊法）测定法在效价测定的灵敏度、重现性和有效性方面进行了比较。在两种测定法中对TPA的参考制剂进行了滴定：在显色测定法中，剂量-反应曲线不平行，而在凝块溶解测定法中观察到平行性。因此，显色测定法的适用性有限，不符合任何常规监管用途的要求。单个批次的重组（r）TPA的效价只能通过自动凝块溶解测定法以TPA活性的国际单位（IU）来估计，并且获得的效价值（IU/瓶）与制造商的值非常接近。
