Pharmaceutical Study of Allopurinol Gargle Containing Glycerin.

One of the side effects of cancer chemotherapy is the occurrence of stomatitis. Many studies have shown the effectiveness of a 0.1% allopurinol gargle for treating such stomatitis. Allopurinol gargle develops crystalline deposition a few days after preparation, and therefore it should befreshly prepared each time before use.We developed a prescription that delays crystalline deposition by adding glycerin to allopurinol gargle.Sterile allopurinol gargle (sterile ALT) was prepared by crushing allopurinol tablets, and then glycerin was added at various concentrations.The dissolved amount after 30 days was 0.65±0.05 mg/mL in sterile ALT without glycerin (sterile G0-ALT), 0.75±0.01 mg/mL in sterile ALT containing 1% glycerin (sterile G1-ALT), 0.79±0.03 mg/mL in sterile ALT containing 3% glycerin (sterile G 3-ALT), 0.89±0.06 mg/mL in sterile ALT containing 5% glycerin (sterile G 5-ALT), and 0.98±0.01 mg/mL in sterile ALT containing 10% glycerin (sterile G 10-ALT). The dissolved amount increased with the glycerin concentration.Allopurinol crystal deposition was observed after 2 days in sterile G 0-ALT, after 3 days in sterile G 1-ALT, after 6 days in sterile G 3-ALT, and after 10 days in sterile G 5-ALT, but could not be detected even after 30 days in sterile G 10-ALT.In tests of the sensation tastes during use in normal subjects, similar results were obtained between sterile G 10-ALT and sterile G 0-ALT. The xanthine oxidase (XOD) inhibitory activity was also similar between the two gargles.These results show that sterile G 10-ALT can be preserved for 30 days at 25°C, and its effects and sensation during use are similar to those of a prescription not containing glycerin.