251 NM
The base value of this structure is 253 nm. There are 4 alkyl substituents which add a value of 20 (4x5 nm). So the lambda max of this structure is 273 nm.
The lambda max is 510 nm.
The reported UV lambda max of Vildagliptin drug is 254 nm.
Just write this as lambda/4, or (1/4)lambda. You can't get a numerical value, unless you know the value of lambda.
intrinsic property
495
236nm
520 nm
uv max of pregabalin are following: 1.in water 276nm 2.in methanol 210nm
254 nm
using uv-visible spectrophotometer concentration vs absorbance is plotted and the maximum absorbance of the drug is lambda max of the drug. then after it will decrease. still if needed clarification, refer beer lambert"s law