EVALUATION OF PEG 4000 SOLUTION STABILITY IN DIFFERENT TEMPERATURES AND ENVIRONMENTAL CONDITIONS OVER THE TWELVE MONTHS

Background & Aims: Polyethylene glycol (PEG) solution is used as a laxative for the treatment of constipation in children. Due to the preparation of this solution as a compounding ingredient and solution instability as well as unavailability of the exact expiration date of compounding ingredients, it is necessary and important to investigate the stability of PEG solution. Materials & Methods: In order to assess the stability of PEG solution, the prepared solutions were stored in various environments (ambient light and temperature, oven, refrigerator and exposed to constant light) for twelve months. Then, they were evaluated for changes in the physical appearance and odor, pH, electrical conductivity, viscosity, refractive index, and microbial contamination over twelve months. Results: No change in color, turbidity and odor as well as no microbial growth was observed among any of the samples during the study period, which indicates no polymer precipitation and no microbial contamination. Moreover, there was almost no change in FTIR spectra of all samples over the study period. Samples stored in the refrigerator underwent significant changes in pH, refractive index and viscosity after three months, while samples stored in the oven and exposed to light underwent significant changes from the first month. Conclusion: Considering the destructive effects of light and temperature on PEG solution stability, which can accelerate the aging process, release organic acids and reduce the pH of the solution, the prepared PEG solutions are recommended to be packaged in dark glass containers (due to incompatibility with many plastic containers), stored at a temperature below 25 ° C (preferably in the refrigerator) and finally used up to one month after product preparation.