The Physical Compatibility of Orphenadrine Citrate with 0.45% Sodium Chloride, Lactated Ringer's Solution, and Plasma-Lyte A.

BACKGROUND

The physical compatibility of orphenadrine citrate has only been reported in 0.9% sodium chloride in combination with diclofenac. The objective of this study was to investigate the physical compatibility of orphenadrine citrate mixed with 0.45% Sodium Chloride (0.45% NaCl), Lactated Ringer's (LR), and Plasma-Lyte A (PLA).

METHODS

Triplicate samples at 0.24 mg/mL, 0.6 mg/mL, and 1.2 mg/mL orphenadrine were mixed in each study fluid. Physical compatibility was assessed through visual observation, spectrophotometric absorbance, and pH analysis. Samples were assessed at hours 0, 1, 5, 8, and 24.

RESULTS

In all test samples, there were no changes observed or measured regarding visual inspection and spectrophotometric analysis. The pH measurements remained stable in 0.45% sodium chloride through 24 hours and through 1 hour with LR at the 0.24 mg/mL concentration. In all samples containing PLA, changes greater than 0.1 unit from baseline across all studied concentrations of drug were recorded from 1 hour onwards.

CONCLUSIONS

Orphenadrine citrate is physically compatible with 0.45% NaCl for up to 24 hours. LR and PLA were classified as physically incompatible beyond 1 hour due to significant changes in pH. An evaluation of chemical stability is needed to support these findings.