Determination of methotrexate and its metabolites: 1. Determination methods developed till 2000: In this era the methotrexate was being used only as anti tumor agent to treat acute leukaemia, osteosarcoma, psoriasis, sarcoidosis and wegener’s granulomatosis. Due to its toxic side effects such as skin rash, myelo suppression, renal damage and mucosal ulceration the biological fluid level of methotrexate came into existence. The side effects was only when this drug was used in higher concentration. The biological fluids used were serum, urine and cerebrospinal fluid. The determination method initially described in early 60s by the Werheiser and co-workers. After that with the advancement of techniques this enzymatic method was simplified by various …show more content…
Methotrexate is oxidized to 2, 4-diaminopteridine 6- carboxylic acid, which is a fluorescent product that is separable from other fluorescent material in plasma with the use of C18 column. This technique is the advancement and a boom in the MTX determination as compared to previous enzymatic methods, competitive protein binding, radioimmunoassay and spectrofluorometry. After the invention of this more specific and sensitive method various research groups modifies these method for the more precision and more sensitivity out of which Salamoun group and Angelis stofordis groups were the most important groups. Salamoun came into existence in 1986-87 with their modified liquid chromatography method. They also analyse the metabolites of methotrexate i.e. 7-hydroxymethotrexate and 2, 4-diamino-N-methylpteroic acid in the biological fluids mainly Heparinized plasma and urine samples. The author claim the less noise and no interference of any other component peak in this method as compared to previously described …show more content…
As reported the low levels of MTXPG were associated with poor clinical status and patients with MTXPG levels <60nM were fourfold more likely to have a poor response to MTX. Hence the poor response to MTX was associated with a low formation of RBC MTXPG levels. The poor response was also associated with high MTX dose administration as the clinicians’ escalated the dose to decrease disease activity. Depleted erythrocyte folate PG levels appeared to be an important determination of response. The genetic factors also lead to the Drug