Unicorn horn – what else can we find in a painkiller more than 200 years old?

Period pharmacy operated by Capuchins.
Source: doc. Karel Nesměrák

The preparation is called Laudanum opiatum caesareum (Imperial opium laudanum) and dates back to the second half of the 18^th century. This black powder was prepared by a pharmacist in a period pharmacy operated by the order of Capuchins in Prague’s Hradčany quarter. In addition to opium, the analysed preparation contains many other compounds, including pearl extract, coral extract, or unicorn horn. Various fossil remains and narwhal tusks were considered to be the horns of unicorns at the time. These components exerted mainly psychological effects due to their rarity and were considered universal antidotes at that time. The recipe further called for saffron, powdered gold, and other compounds which served as flavouring to remove the bitter taste of opium. Among these were amber and musk, often used in modern day perfumes, and a variety of essential oils – this specific recipe mentions cinnamon, lemon, clove, and nutmeg oil.

Pharmaceutical jar in which the preparation has been stored for over 200 years and the original recipe from 1729 in Latin.
Source: original article

Because the composition of the preparation is so complicated, a multi-analytical approach is required. There is no method that will precisely determine all chemical components of this preparation on its own. Therefore, inorganic substances were determined by gravimetry and then identified using atomic absorption spectrometry which is able to identify individual chemical elements. This revealed lower levels of calcium than expected and no traces of gold were discovered. This could have been due to the period pharmacist altering the recipe due to the high price of gold. Another method that has been applied is mass spectrometry in association with liquid or gas chromatography. This was used to identify traces of organic compounds. Using this procedure, alkaloids were confirmed (e.g., morphine and codeine which are used as analgesics to this day) and traces of saffron and nutmeg oil were found. Volatile compounds were determined using solid-gas extraction and by measuring the concentration of gaseous compounds. No traces of lemon oil were found but the preparation contained pine resin, despite not being mentioned in the recipe.

In a previous study, the team led by doc. Nesměrák proposed dating opium preparations using the ratio of noscapine and cotarnine – two opium alkaloids. Cotarnine is a direct decomposition product of noscapine. Fresh preparations contain over 100 times more noscapine, a ratio that decreases over time. For preparations older than 200 years, the ratio should be between 0.4 and 3.8. The ratio of the analysed product was 0.45, which further confirms this dating method.

Using a multi-analytical approach, scientists managed to identify most of the components in Laudanum opiatum caesareum dating back to the second half of 18^th century. The preparation was used during this period as a pain killer. The presence of several volatile compounds was surprising as the preparation has been stored under unknown conditions for more than 200 years in an unsealed container. Because period pharmacists did not always follow the recipe precisely and often altered it, the comparison of the recipe and the real composition is extremely interesting. In this case, most of the original recipe was confirmed along with a few alterations made by the period pharmacist.

Magda Křelinová

Nesměrák, K., Štícha, M., Belianský, M. et al. Laudanum opiatum caesareum: authentication of the composition of a historical pharmaceutical preparation from the eighteenth century using a multianalytical approach. Monatsh Chem 152, 1089–1096 (2021).