My physician instructed me to uncap one respule, instill one drop per night into my nebuliser, until I finish the respule. Each respule contains enough liquid to last a week. But my physician warned that once you tear off a cap (I added a red line to indicate where, in the picture below), you can't reattach the cap to the respule. The respules don't come with caps! My physician advised putting opened respules in an upright airtight container, like a empty pill bottle which the pharmacy can gift for free (as I'm buying the respules from them), then capping the bottle with the exposed respule inside.
But I can't keep this bottle plumb whenever I'm flying! Whenever the bottle topples in my bag or carry-on luggage, the fluid in the respule spills out!
Anyone got better ideas? How can I cap these respules, so that even if a respule tips over, nothing from the respule leaks?

