Stability of sample solution as a crucial point during HPLC determination of chemical purity of temozolomide drug substance

- HPLC method for purity determination of temozolomide drug substance was developed.
- It is crucial to control stability of both temozolomide and its degradation product.
- We proposed a novel approach to analysis of substance which is unstable in solution.
- Mathematical correction eliminates the necessity to analyse freshly dissolved samples.