A free base form of Lapatinib Ditosylate.Formula:C29H26CIFN4O4SSolubility:DMSO (~200mg/ml)Molecular Weight:~581.06Storage and Stability:Lyophilized powder may be stored at -20°C. Stable for 12 months at -20°C. Reconstitute with sterile buffer or dH2O. Aliquot to avoid repeated freezing and thawing. Store at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.