Ensuring the safety of aseptic mixtures of injection drugs is one of the most important tasks of hospital pharmacists.At Asahikawa Medical College Hospital,we have established an“Aseptic Injection Mixture Center”,where we aseptically mix injection preparations containing parenteral nutrition agents and anti-cancer drugs for in- and out-patients,in collaboration with nursing staff.To solve the problem of the small amount of available data on the stability of anti-cancer drugs when mixed with injection solutions,we calculated pseudo-first-order rate constants for the disappearance of anti-cancer drugs in distilled water for injection,saline and 5% glucose solution using stability data in the literature,and also obtained Arrhenius parameters.Using them,we determined expiration dates,the times at which 95% of active elements remained in the injection mixture,and based on this assigned 43 anti-cancer drugs to 4 categories:“mix on use”, “use within 24 hr”,“use within 2 days”and“use within 3 days”.Drugs categorized as“use within 3 days”accounted for around 50% of anti-cancer drugs used in our hospital.
The data we obtained has been extremely useful in the provision of aseptic mixtures by our hospital pharmacists and the method of predicting the stability of anti-cancer drugs in injection solutions could be applied to other injection drugs as well.