Investigation of 2,4 Di-tert-butylphenol Leaching from Multidose Ophthalmic Devices into Tacrolimus Micellar Formulations

Short contacts between medical devices and medications that they contain can cause drug sorption or leaching of unwanted compounds which can have clinical consequences. However, the parameters that govern these interactions are still incompletely understood. The objectives of this study were to evaluate the impact of the formulation parameters on migration of 2,4 Di-tert-butylphenol (2,4 DTBP) and sorption of tacrolimus (TAC) in a model micellar ophthalmic drug formulation which is known to interact with silicone elastomers. A design of experiments was established to evaluate the impact of the formulation parameters on 2,4 DTBP leaching and tacrolimus sorption by varying the initial concentrations of TAC (0.04; 0.2 and 1 mg/mL), polyoxyethylenated castor oil (KEL) (32; 80 and 200 mg/mL) and ethanol absolute (EtOH) (10 and 100 mg/mL), at 5°C and 25°C, during static contact between various formulations and silicone valves obtained from an ophthalmic multidose delivery device. Concentrations of 2,4 DTBP and TAC were monitored by liquid chromatography coupled with an UV-visible detector. Under the conditions studied, the amount of 2,4 DTBP leaching out increased during contact with the silicone valve, with increasing TAC concentration being quite interestingly the main factor decreasing its ability to leach out, whilst ethanol increased its leachability. The silicone valve did not cause any significant decrease of TAC concentrations over the duration of the study, regardless of the concentrations of KEL, EtOH, or temperature. This study showed the impact of formulation on the leaching of 2,4 DTBP from a silicone component.