Background: In the manufacturing of the Acyclovir drug substance, that there are some
process solvents, which includes Benzene, Hexamethyldisilazane (HMDS) and Methylcyanoacetate, are
used. These are toxic to human health. These residual solvents in the drug substance are required to
have an analytical method to detect these impurities in the lowest possible level in order to ensure the
human safety and drug efficacy. There is no method to determine these solvents which are specific to
this drug substance.
Objective: The objective of the research work is to develop the accurate and robust analytical method to
determine the toxic impurities present in the Acyclovir drug substance to the lowest possible level.
Method: The method uses the GC-MS in order to determine the impurities in the lowest possible detection
Result: The method was taken for critical analytical method validation parameters and observed that
specificity, linearity and LOQ were found satisfactory. The LOQ of the Hexamethyl disilazane
(0.0042mg/ml), Benzene (0.0003mg/ml) and Methylcyanoacetate (0.0001mg/ml).
Conclusion: The method shall be applied for Toxic/GIs of HMDS, Benzene and Methylcyanoacete
present in the Acyclovir drug substance. This method shall also be applied for other APIs by optimizing
the instrument parameters and sample preparations.