# How does the acidity of soft drinks not affect certain drugs, such as opiates? What about drugs and stomach acid?

Here's a very random introduction. I heard the term, "dirty Sprite" (it's some rap album/slang term) on a YouTube advertisement. I Googled "dirty Sprite", and it's apparently a recreational drug: codeine syrup in Sprite lemon-lime soda. People allegedly get high off of it, meaning the opiates in codeine is metabolized properly. My question is, how does harsh acidity of the Sprite (pH of 3.4-3.8 if you trust Google) not interfere with the codeine structure and mitigate its metabolism?

Then, this turned into a meta philosophical question: how does the acidity of the stomach, which is more acidic than Sprite, not interfere with not only codeine, but other substances?

• pH 3.4-3.8 is hardly harsh acidity. – bon Aug 3 '15 at 18:49
• I wouldn't believe this is really off-topic, but it's borderline, at least. I reckon most of the knowledge required to answer this is chemical and pharmaceutical knowledge. – M.A.R. Aug 3 '15 at 19:27

Many drugs are not very soluble in water what is a common property for a lot of organic substances, including Codeine. Therefor it is very common to turn them into their hydrochlorid which is simply $\text{Drug}\ce{.HCl}$. [4] E.g., Crystal Meth got it's name from the crystals that the hydrochloride forms.

$\hskip1.7in$
Source: Wikimedia Commons

Other examples are, e.g., Cocaine, Cetirizine, hydroxyzine, and many more.

As your substance is either the hydrochloride or would turn into the hydrochloride in stomach there should not be any destructive influence on the structure of the drug. In fact it even promotes the absorption.

On the other hand, the better solubility of the corresponding hydrochloride is a relatively big problem for those drugs that should not get absorbed in the stomach. They need to be coated to "survive" the stomach acidity to reach the intestine where they should get absorbed.

• Thank you, it had not occurred to me think that stomach acidity is an integral part of digestion in itself. – Alvin Nunez Oct 3 '15 at 19:06
• Heroin base is notoriously dissolved in citric acid (with heat applied) in order to make it soluble for injection. Do you think that the citric acid in the dirty Sprite would have the same effect on the codeine, making a soluble citrate which absorbs quicker into the bloodstream than codeine tablets? – jwg Sep 7 '17 at 8:04
• @jwg at least it sounds plausible – pH13 - Yet another Philipp Sep 7 '17 at 8:28
• Thanks! It seems like various concoctions taken recreationally involving codeine (such as 'purple drank', which combines it with anti-histamines) are intended to accelerate its metabolism in order to achieve heroin-style euphoria. – jwg Sep 7 '17 at 9:08