Comparaive studies on antisickling properties of thiocyanate, tellurite and hydroxyurea

ABSTRACT

Thiocyanate, hydroxyurea and tellurite are among chemical agents being used as antisickling drugs and currently receiving attention for research. The antisickling properties of these drugs was investigated and compared in this study. Human sickle blood was incubated with the drugs in vitro at concentrations related to the dose used by patients in vivo. Haemoglobin function and specific aspects of the sickling process were then measured by employing standard methods used in screening potential antisickling agents. All the drugs significantly inhibited [P<0.05] sickling of deoxygenated sickle blood and formation of irreversibly sickled cell in a dose and time-dependent manner. Thiocyanate, hydroxyurea and tellurite inhibited sickling optimally at 20mM, 40mM and 50mM respectively. Thiocyanate and hydroxyurea prolonged sickle red blood cell life span as indicated in the significant decrease in haemolysis and osmotic fragility while tellurite increased these blood parameters. The three drugs also caused significant prolongation of delay time of haemoglobin S [HbS] polymerization while thiocyanate and hydroxyurea significantly increased [P<0.05] both solubility ratio and oxygen affinity of HbS. Results obtained in this study suggest that the three drugs have remarkable antisickling potential in vitro with thiocyanate being the most efficient followed by tellurite