Determination of Beyond use date of Sodium bicarbonate gargles according to Storage temperature conditions

Hee-Jung Leeo, Yeon-Joo Lee, Ok-Sun Park, Jae-Yeon Kim, Young-Chun Song and Hye-Sun Gwaka

Department of Pharmacy, Asan Medical Center, College of Pharmacy, Ewha Women’s Universitya

Background: Sodium bicarbonate is white, odorless, and crystalline powder used for various purposes, such as an alkalinizing agent and antacid. Sodium bicarbonate dissolved in normal saline can be topically applied as mouthwash for preventing oral mucositis after radiation therapy. In this study, the stability of sodium bicarbonate solutions in normal saline at room temperature (RT) and refrigerator was evaluated.

Methods: Sodium bicarbonate solution was prepared by dissolving 2g sodium bicarbonate powder in 500 mL normal saline. These test solutions were prepared in triplicate. Sodium bicarbonate concentrations were calculated by carrying out neutralization titration with 0.1M HCl. pH values were measured using pH meter. According to the Korean Pharmacopoeia, pH range of 7.9-8.4 was regarded as stability-indicating criterion. Sodium bicarbonate contents and pH values were measured on day 0, 7, 15, 23 and 30. The appearance of test solutions was observed for physical changes. Ten milliliter of each solution was cultured in order to identify microorganisms and fungi.

Results: Sodium bicarbonate concentrations of all test solutions were above 90% at day 30 regardless of storage temperature conditions. For test solutions stored in RT, 95% confidence interval values of pH were within 7.9-8.4 for 7 days, whereas those at refrigerator remained within 7.9-8.4 for 15 days. No foreign substance was detected by visual inspection during 30 days.

Conclusion: Based on the results, it was concluded that sodium bicarbonate gargle was stable for up to 7 and 15 days at RT and refrigerator, respectively.

주제어 : sodium bicarbonate, mouthwash, gargle, beyond use date