Nontherapeutic equivalence of a generic product of imipenem-cilastatin is caused more by chemical instability of the active pharmaceutical ingredient (imipenem) than by its substandard amount of cilastatin
Fig 3
Chemical and physical stability.
Comparison of pH (A) and colorimetric changes (B) at room temperature (25°C) of a generic product and the innovator of imipenem-cilastatin during the first 24 hours after powder reconstitution.