Background: Methotrexate (MTX) is a mainstay drug in the treatment of psoriatic and rheumatologic conditions. Subcutaneous MTX has become a feasible treatment alternative with the development of prefilled syringes or autoinjectors containing MTX solution that can be self-administered by the patient at home. However, MTX prefilled auto-injector pens are still not available in some countries.
Objective: This study aimed to investigate the stability and sterility of 25 mg/mL MTX solution in a disposable plastic syringe over a 12-week period under light protection at temperatures of 4 °C, 25 °C, and 37 °C.
Methods: This study was conducted during November 2019 to February 2020 at the Faculty of Medicine Siriraj Hospital, Mahidol University. Stability was evaluated using ultra-high-performance liquid chromatography technique, and sterility was assessed by cultures for bacterial and fungal contamination.
Results: Our results revealed that patient-ready syringes containing 25 mg/mL MTX solution can be prepared in advance and kept for up to 12 weeks under light protection, and they can be kept at temperatures ranging from 4 to 37 °C.
Conclusion: This system for delivering MTX to patients that are refractory to or intolerant of oral MTX via a self-administered pre-filled syringe is both efficient and easy to implement in care settings where commercially alternatives are not yet available.
Keywords: 25 mg/mL methotrexate; 4 °C to 37 °C; patient-ready syringes; psoriatic and rheumatologic conditions; temperature.