i ready try 100microg/ml conc.solution with further dilution 2-20micro g/mlin phosphte buffer 6.8 and 0.1 M HCl as solvent at wavelength scan 200-400nm.
yes sir you r rite .peak of drug was not detected on wavelength scane.thats why having no idea about lamda max. but according literature it is 227 nm.and 1mg/ml solution gives max.absorbance 0.064