THE

AMERICAN JOURNAL OF PHARMACY.

JANUARY, 1872.

ILLUSTRATIONS OF SOME PHARMACEUTICAL PROCESSES AND APPARATUS,

As Exhibited to the Class in the Philadelphia College of Pharmacy.

BY PROF. E. PARRISH.

The illustration of a course of lectures in Pharmacy gives an opportunity for noting carefully details and results which in common practice are overlooked or, if observed, are not made public.

The processes detailed in this essay were conducted at the Philadelphia College of Pharmacy, in presence of the large class of students, with such facilities only as a lecture-room, with its counter, sink, hydrant, and gas-supply afford.

The energies of the lecturer being mainly directed to explanation and oral instruction, an assistant is employed in the management of the several processes simultaneously going on during the lecture; to his skilful assistant, Jos. P. Remington, the writer acknowledges himself indebted for useful suggestions, especially in the construction of the steam evaporating apparatus herein described.

Immediately after a statement of the scientific facts and principles pertaining to the generation and application of heat in pharmacy, the process of evaporation and the apparatus suitable for the preparation of extracts are brought into view, models and drawings are used for some, while evaporating dishes, sand-baths, steam-baths and water-baths are shown in actual use.

The annexed drawing shows a steam-boiler, evaporating pan and still-head constructed for the purposes of this course of instruction. A is a boiler of inch thick (No. 10 wire gauge), copper, 1 foot 9 inches long by 7 inches in diameter. It is held in position by a stout iron

frame, at an elevation of 12 inches, so as to allow of a stand of 8 Bunsen burners to be so placed as to spread a clean flame over the entire length of the bottom. Each of these burners has a tube inch diameter and 5 inches long. The water supply pipe, which is seen on the extreme left, is inch in diameter, and has a valve at H which closes when not in use. The two small water-cocks are designed to ascertain the elevation of water in the boiler. A inch steam pipe connects the boiler with the steam jacket.

The evaporating pan B, set in an iron frame 20 inches high, consists of a concave dish of tinned copper, 1 foot in diameter, 6 inches deep, with a steam jacket and a brass flange 1 inch wide riveted on to it.

The dome, C, is of copper, and has a similar flange, by which it is designed to be clamped on to the evaporating pan when the apparatus is used for distillation. This junction is made steam tight by a coil of lamp wick interposed between the flanges. The drip pipe from the steam jacket empties into the adjacent sink; it is, for convenience, readily separable. The steam pipe being connected by a coupling the different parts of the apparatus may with facility be separated from each other. The gas burners are connected by elastic tubing with a T pipe in the counter.

The first preparation made in this apparatus was Extractum Gentiana, U. S. P. The percolation was previously started in a cylinder of tinned iron, with a stop-cock attached. 96 troy ounces (6 lbs. 9 oz. av.) of ground gentian, somewhat coarser than that which would pass through a No. 40 sieve, was macerated in sufficient cold water thoroughly to saturate it, then packed in the percolator and water added till about a gallon of dense percolate had passed. This was intro

duced near the beginning of the lecture into the evaporating pan, and steam turned on. In a few minutes the liquid was in active ebullition; after boiling a short time it was removed and strained, but without yielding a precipitate of insoluble matter; the strained liquid returned was rapidly inspissated till the close of the lecture. The percolation continued yielded about two gallons additional of percolate, which with the first portion was evaporated in the interim to a soft pilular consistence, and the finished extract exhibited at the following lecture. The product weighed 2 lbs. 11 oz. av., 41 per cent., which might have been somewhat increased if the percolation had been longer continued, though without profit. The gentian, at 16 cents per lb., which included the cost of powdering, cost $1.08; the fuel may be estimated as costing 36 cents. The extract, therefore, cost in the aggregate $1.44, 52 cents per lb. It was of superior quality, of rich brown color, and with a decided odor of the root.

Extractum Jalapæ, U. S. P.

Two pounds, avoirdupois, of finely powdered jalap was moistened with six fluidounces of alcohol, sp. gr. 835, and packed in a strong ten-inch glass funnel, which was suspended over a suitable receiving vessel. Alcohol was added till about four pints of tincture had passed; then water was gradually poured on, and its progress watched till it had nearly reached the perforated cork diaphragm fitted above the neck of the funnel. Another receiver was now substituted, and, the supply of water being kept up, 6 pints of aqueous percolate was received. The success of the last part of this process was more complete than was anticipated with so fine a powder of jalap, a perforated cork diaphragm of about 2 inches diameter being used, and the shape of the funnel favoring the swelling of the powder on the addition of water, without unduly compacting it, so that when the aqueous menstruum had begun to pass, the dropping continued moderately fast throughout. The quantity of menstruum, though less than that indicated in the Pharmacopoeia, was limited to such amount as could be conveniently evaporated during the time at our disposal, and, as the result proved, gave a fair yield of extract.

At the second lecture on extracts the alcoholic percolate from the jalap was introduced into the evaporating pan, and the dome clamped on to it, as shown in the drawing; and to this a large glass Liebig's condenser was attached, and connected with the hydrant and sink by

elastic hose. Steam being generated, which occupied about ten minutes, the alcohol was rapidly recovered, and at the close of the lecture, the dome being removed from the pan, a dry mass of resinous extract was obtained, which weighed 6 oz. (av.) and 40 grs., nearly 21.4 per cent. of the jalap used. The alcohol had scarcely lost in quantity, but was not free from the odor of the drug. The aqueous percolate was evaporated to a syrupy consistence, after the lecture, removed from the pan, and divided into two equal parts. The resinous mass was dissolved in a pint of the recovered alcohol, and also divided into two equal parts. A half part of the resinous and aqueous liquids were now mixed, as directed in the process of the Pharmacopoeia for the whole, and the mixture being evaporated gave 6 oz. of an excellent dry hydro-alcoholic extract.

Two pounds of jalap having been used, this quantity, being one-half the whole yield, represents the yield per pound = 39 per cent. The powdered jalap cost 65 cents per pound, the alcohol (half the quantity used) 55 cents, the heat, estimated, 20 cents, giving an aggregate cost of the 6 ounces, $1.40. Deducting alcohol recovered and useful for a similar process, 50 cents, we have a cost of 90 cents, or $2.14 the cost of a pound, less than half the market price of the best extractum jalapæ.

The object in setting aside half of the alcoholic solution of resinous extract was to ascertain the proportion it would yield of the officinal resina jalapæ. Accordingly, at the next lecture it was diluted to half a pint and added to 4 pints of water. The precipitate, washed by several portions of water, collected and dried, yielded 2 ounces of the officinal resina jalapæ, or 12 per cent. of the jalap used. The cost of this was about 70 cents per ounce.

The question of economy in evaporation is of practical interest in connection with the preparation of these extracts by the use of a steam boiler, and is an element of inaccuracy in these estimates. The process being suspended and resumed involves a loss of fuel, and there is no doubt but that much waste occurs from there being too many burners under the boiler. Six burners instead of eight would serve the purpose, though the rapidity of getting up steam would be lessened.

Extractum Nucis Vomica, U. S. P.

Twelve troy ounces of finely powdered nux vomica, moistened with four fluidounces of alcohol, were introduced into a cylindrical glass