Health and Medicine Question #221

Rachel, a 12 year old female from the Internet asks on October 24, 2001,

I am doing a science fair project to measure which type of ibuprofen dissolves fastest in stomach like solutions. ie will gelcaps dissolve faster than caplets etc. How can I measure the acidic ph's I will need? I know that too acidic a solution may burn my skin, but I researched that Coca Cola has a ph of around 2.5 therefore this should be safe shouldn't it? I have ph papers but they only measure from ph 5.0 and up. Will I need a ph meter? If so where might I get one from?

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The answer

Barry Shell answered on October 24, 2001

I think Coke will be safe for the short period you will be touching it. You could also wear rubber gloves. Stomach acid is hydrochloric acid at a pH of 1 and you would not want prolonged contact with that level of acidity. You can get pH papers that measure all the way from 1 to 14, or you can get other kinds that measure very fine differences in particular regions of the scale--like from 1 - 6. You might try local high school or university labs. Maybe an older brother or sister could check for you. I don't think you need a pH meter. Good pH paper should be fine. I did a google search and found this Canadian laboratory supply house that sells pH paper.

Ibuprofen is not very soluble in water, but very soluble in acetone, methanol, and ether.

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