Development of new thrombolytic agents using recombinant DNA technology

The effects of age and gender on the pharmacokinetics and pharmacodynamics in healthy subjects of the plasminogen activator, lanoteplase

AIMS

To investigate the influence of age and gender on the intravenous pharmacokinetics and pharmacodynamics of the plasminogen activator, lanoteplase.

METHODS

Forty healthy subjects (10 each of young males, elderly males, young females and elderly females) received a single bolus 10 kU kg(-1) intravenous dose of lanoteplase. Plasma from blood serially collected for 24 h post-dose was analyzed for lanoteplase (antigen), fibrinogen, plasminogen and α2-antiplasmin concentrations, plasma plasminogen activation activity (PPAA) and rapid plasminogen activator inhibitor (PAI-1).

RESULTS

Lanoteplase mean total systemic clearance (CL(t)) values ranged from 1.9 to 2.8 l h(-1) and mean steady-state volume of distribution (V(ss)) values ranged from 12.3 to 15.6 l. Age-by-gender interactions were observed for lanoteplase CL(t) (P= 0.04), but no differences were observed for V(ss) or elimination half-life. Elderly females had a 27% lower mean CL(t) than young females (95% CI for the difference 0.17, 1.27 l h(-1)) and 32% lower CL(t) than elderly males (95% CI for the difference 0.15, 1.65 l h(-1)). PPAA AUC/dose values did not show an age-by-gender interaction. Haemostasis parameters indicated only a slight degree of systemic plasminogen activation.

CONCLUSIONS

Elderly females had a lower mean lanoteplase CL(t) than elderly males and young females. However, no difference was observed between young and elderly females for the AUC/dose of PPAA. In addition, there were no age-related or gender-related differences observed in the other pharmacodynamic parameters measured.

Streptokinase—the drug of choice for thrombolytic therapy

Thrombosis, the blockage of blood vessels with clots, can lead to acute myocardial infarction and ischemic stroke, both leading causes of death. Other than surgical interventions to remove or by pass the blockage, or the generation of collateral vessels to provide a new blood supply, the only treatment available is the administration of thrombolytic agents to dissolve the blood clot. This article describes a comprehensive review of streptokinase (SK). We discuss the biochemistry and molecular biology of SK, describing the mechanism of action, structures, confirmational properties, immunogenecity, chemical modification, and cloning and expression. The production and physico-chemical properties of this SK are also discussed. In this review, considering the properties and characteristics of SK that make it the drug of choice for thrombolytic therapy.

Natural products with hypoglycemic, hypotensive, hypocholesterolemic, antiatherosclerotic and antithrombotic activities

This article reviews compounds of botanical origin which are capable of lowering plasma levels of glucose and cholesterol and blood pressure, as well as compounds inhibiting atherosclerosis and thrombosis. Hypoglycemic natural products comprise flavonoids, xanthones, triterpenoids, alkaloids, glycosides, alkyldisulfides, aminobutyric acid derivatives, guanidine, polysaccharides and peptides. Hypotensive compounds include flavonoids, diterpenes, alkaloids, glycosides, polysaccharides and proteins. Among natural products with hypocholesterolemic activity are beta-carotene, lycopene, cycloartenol, beta-sitosterol, sitostanol, saponin, soybean protein, indoles, dietary fiber, propionate, mevinolin (beta-hydroxy-beta-methylglutaryl coenzyme A reductase inhibitor) and polysaccharides. Heparins, flavonoids, tocotrienols, beta-hydroxy-beta-methylglutaryl coenzyme A reductase inhibitors (statins), garlic compounds and fungal proteases exert antithrombotic action. Statins and garlic compounds also possess antiatherosclerotic activity.