Sunday, March 29, 2015

The art of using syrups to disguise bad tasting drugs

Cherry morphine cough syrup
The chloroform accentuates the cherry notes (Source)

In the past, many medicines were formulated as liquids. If a drug was soluble in water, a pharmacist would often mix it with a flavoured syrup (water + lots of sugar). This provided a more enjoyable experience for the person taking the medicine, particularly since many drugs taste awful. Over time, it was realized certain syrup flavours paired particularly well with certain unpalatable drugs. Here are a couple of combinations reported in the first edition of Goodman & Gilman, a classic pharmacology textbook:
  • Syrup of licorice worked well with salts such as sodium bromide (used as a sedative and treatment for epilepsy) as the sweetness and licorice flavour both helped to cover up the salty taste
  • Syrup of raspberry and syrup of lemon were effective at masking sour tasting drugs, which historically included such things as dilute solutions of hydrochloric acid (used to treat achlorhydria, which is when your stomach stops producing acid)
  • Syrup of acacia (Acacia is a large genus of plants, the aboveground parts of which often contain large amounts of tannins, which are compounds responsible for the astringency/dryness of wine) was used to disguise the burning taste of urea (used as a diuretic)
  • Aromatic syrup of eriodictyon (yerba santa) (refers to Eriodictyon californicum, a shrub native to the western United States known to produce flavour-modifying compounds) was considered a "therapeutic masterpiece" owing to its ability to mask the bitter taste of alkaloids (e.g. codeine, quinine)
  • Syrup of cocoa also worked well with alkaloids (presumably because chocolate is delicious)
  • Syrup of cinnamon was used with with sodium salicylate (bitter), ammonium ferric citrate (bitter), and ammonium chloride (salty and astringent)



References

Goodman L, Gilman A. 1941. The pharmacological basis of therapeutics. Macmillan Company.

Ley JP, Krammer G, Reinders G, Gatfield IL, Bertram HJ. 2005. Evaluation of bitter masking flavanones from Herba Santa (Eriodictyon californicum (H. and A.) Torr., Hydrophyllaceae). Journal of Agricultural and Food Chemistry 53(15):6061-6066.