Contribution from the Pharmaceutical Laboratory, Philadelphia College of Pharmacy.
By EDWIN C. LESHER.
Read at the Pharmaceutical Meeting, November 15.
A series of experiments were tried to ascertain the best menstruum that would produce a clear percolate charged with the active properties of the drug. Alcohol and water employed in varying proportions were used. The result is as follows:
|Burdock root, No. 60||8 oz. av.|
|Diluted alcohol, sufficient quantity for||8 fl. oz.|
Moisten the powder with 2 oz. av. of the diluted alcohol, and pack it firmly in a cylindrical percolator; then add enough diluted alcohol to saturate the powder and leave a stratum above it; when the liquid begins to drop from the percolator, close the lower orifice, and, having closely covered the percolator, macerate for forty-eight hours. Then allow the percolation to proceed gradually, adding diluted alcohol until the burdock root is exhausted. Reserve the first 6 1/3 fluid ounces of the percolate. By means of the still, distil off the remainder of the alcohol, and evaporate the residue to a soft extract; dissolve this in the reserved portion, and add enough diluted alcohol to make the fluid extract measure 8 fluid ounces. This affords a very dark wine-colored preparation, of a strong odor, remaining permanently clear, and possessing the full medical properties.
A second experiment was made with a menstruum composed of alcohol, 2 parts, and water, 1 part, 3 fluid ounces of the mixture being used for moistening 8 ounces of the drug in No. 20 powder. The percolation was conducted as in the first experiment, and the fluid extract was finished in the same manner.
The third experiment differed from the first, in using burdock root in No. 30 powder, and in moistening 8 ounces of this with 3 fluid ounces of diluted alcohol.
In making these fluid extracts the alcohol was recovered by the use of a still, and after having ascertained the specific gravity, which was found to be 0.870, it was easily converted into diluted alcohol by the following calculation: To find the quantity of water to be added, multiply the difference between the specific gravity of the liquid and the desired specific gravity of the mixture by the quantity of the liquid, and divide the product by the difference between the desired specific gravity and that of the water to be mixed with it.
There is nothing more unsightly in the shop of a pharmacist than a bottle containing a liquid with a bulky precipitate. Not only is the appearance objectionable, but possibly the precipitated matter may contain the very substance which should be held in solution. In order to arrive at a satisfactory formula for fluid extract of burdock, it will be found necessary to take into consideration the principal constituents of the root. By comparing the color and properties of the three preparations, the first one, in which diluted alcohol as the menstruum was used, is by far superior to the others. The liquid is clear, and possesses the full properties of the drug.
There has been some demand created for this fluid extract, and it is sold largely in some sections. The dispensing pharmacist can very easily make it himself, and thus be not only sure of the quality, but also affect a saving in the cost. The root is now obtainable, costing about 15 or 20 cents per pound.