Photostability studies on (±)-TRAmadol in a liquid formulation

Manabu Suno, Hidenori Ichihara, Takahiro Ishino, Kento Yamamoto, Yuta Yoshizaki

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1 Citation (Scopus)


Background: Tramadol ((±)-TRA) is recommended for the treatment of mild to moderate cancer pain by the World Health Organization. An oral liquid formulation of (±)-TRA is preferable for patients with a compromised swallowing function. However, the stability of (±)-TRA in aqueous solution has yet to be determined in a clinical setting. The aim of this study was to evaluate the photostability of (±)-TRA in aqueous solution in a clinical setting. Methods: We improved high performance liquid chromatography (HPLC) method for the enantiomeric separation of (±)-TRA, and then the (±)-TRA concentration was determined using HPLC method. We investigated the photodegradation of (±)-TRA in an aqueous solution irradiated with ultraviolet (UV) light: UV-A, UV-B, and UV-C. We also evaluated the stability of liquid formulations of (±)-TRA in a clinical setting by keeping (±)-TRA aqueous solution in normal dispensing bottles and in light-shading dispensing bottles under conditions of both sunlight and diffused light in a room. Samples were collected sequentially over time. Results: (±)-TRA in aqueous solution was degraded the most rapidly when irradiated with UV-C, but was not affected by irradiation with UV-A. No significant difference was observed in the photodegradation behavior of (+)-TRA and (-)-TRA with UV-A, UV-B, and UV-C irradiation. The residual percentages of (±)-TRA were 94.6-104.3% after 14 days in the presence of either sunlight or diffused light in a room, with or without protection from light. Conclusions: These results demonstrated the stability of (±)-TRA in aqueous solution to both sunlight and diffused light in a room. Therefore, liquid formulations of TRA are preserved at room temperature for up to 2 weeks, with or without protection from light. Our results provide additional treatment options with tramadol for pain control.

Original languageEnglish
Article number5
JournalJournal of Pharmaceutical Health Care and Sciences
Issue number1
Publication statusPublished - Feb 5 2015
Externally publishedYes


  • Liquid formulation
  • Photodegradation
  • Photostability
  • Tramadol

ASJC Scopus subject areas

  • Pharmacology (medical)
  • Pharmacology (nursing)


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