Figure 3

Time courses of the residual percentages of (±)-tramadol in aqueous solution contained in normal dispensing bottles (NDBs) and in light-shading dispensing bottles (LSDBs) under the conditions of both sunlight and diffused light in a room. A: (+)-tramadol in aqueous solution contained in NDBs (○) and in LSDBs (●) under the conditions of sunlight in a room. B: (−)-tramadol in aqueous solution contained in NDBs (○) and in LSDBs (●) under the conditions of sunlight in a room. C: (+)-tramadol in aqueous solution contained in NDBs (□) and in LSDBs (■) under the conditions of diffused light in a room. D: (−)-tramadol in aqueous solution contained in NDBs (□) and in LSDBs (■) under the conditions of diffused light in a room. The plots represent the mean ± SD. The residual percentages of (±)-tramadol in aqueous solution at day 7 and 14 were compared with day 0 by the repeated measures ANOVA. A significant reduction in the residual percentages of (±)-TRA was observed between day 0 and 14 in NDBs under the condition of sunlight in a room (* P <0.05).