Lapatinib, Di-p-Toluenesulfonate Salt (N-[3-chloro-4-[(3-fluorophenyl)methoxy]phenyl]-6-[5-[(2-methy

Lapatinib inhibits both epidermal growth factor receptor (EGFR) and HER2/neu (ErbB-2) tyrosine kinases by binding to the intracellular phosphorylation domain, preventing receptor autophosphorylation. The exact site of binding has currently not been confirmed. It appears to arrest the development of breast cancer in some patients with metastatic, treatment-refractory disease. Solubility: Soluble in DMSO at 200mg/ml, very poorly soluble in ethanol, very poorly soluble in water, maximum solubility in plain water is estimated to be about 1-10uM, buffers, serum, or other additives may increase or decrease the aqueous solubility. Elemental Anaylsis: Calculated: , C=54.22%, H=4.76%, Cl=3.72%, F= 1.99%, N=5.88%, S= 10.10%, Storage and Stability: Lyophilized powder may be stored at -20°C. Stable for 6 months after receipt.