This is a pilot, open-label, non-randomized, study to determine the effect that orally administered sulfasalazine has on glutamate levels as measured by MRS and on epileptiform spiking as measured by simultaneous MEG/EEG. The intent of the dose escalation is to determine an Optimal Biological Dose (OBD) based on changes in tumor glutamate levels. The OBD is defined as the dose that has the maximal reduction in tumor glutamate levels after normalization to uninvolved brain.