Description
Creatinine is together with urea, the most widely known "uremic toxin", and is usually assessed when- ever a reduction in kidney function is suspected. This is mainly because creatinine evaluation is cheap, widely accessible and relatively well reflects the renal function. It also forms the basis for estimation of estimated glomerular filtration rate (eGFR) and thus is a major component of all principal eGFR equations.
Creatinine, which is nonenzymatically produced from the creatine pool in skeletal muscle, but is also to some extent generated from exogenous creatine present in meat, is the major guanidine compound retained in patients with diminished glomerular filtration rate. Creatinine is routinely determined in plasma or serum as a measure of impairment of renal function and it might be expected that a variety of uremic symptoms correlate with the plasma creatinine level; this does not, however, necessarily imply a causal relationship. In fact, high serum creatinine levels correlate with low mortality in HD patients, presumably because the creatinine generation rate reflects the size of the muscle mass. Creatinine seems to be relatively nontoxic. Large amounts of creatinine have been fed to healthy subjects without any adverse effects and animals also tolerate large doses.
Purification Methods
Likely impurities are creatine and ammonium chloride. Dissolve it in dilute HCl, then neutralise with ammonia. Recrystallise it from H2O by adding excess of Me2CO. The picrate crystallises from 23volumes of boiling H2O and has m 220-221o(dec). [King J Chem Soc 2377 1930, Beilstein 25 III/IV 2543.]
