FLUID EXTRACTS
Definition perThe U.S.P 9th Edition (pg173)
FLUIDEXTRACTA (Fluidextracts)
Fluidextracts are concentrated liquid preparations of vegetable drugs, containing alcohol either as a solvent or as a preservative, and bearing a uniform relation to the drug used so that one mil of the fluidextract closely represents the activity of one gramme of the air-dried and powdered drug of standard quality.
The fluidextracts of this Pharmacopoeia, with few exceptions, may be classified according to the menstrua used in the extraction of the drugs and the processes of manufacture employed. Several drugs require special manipulation to obtain satisfactory fluidextracts, and for these appropriate formulas have been devised and are printed in full in the text. The following type processes are described, and in each formula the process to be used is designated by reference to the type process:
Type Process A---In this class are included those fluidextracts that are made with a menstruum of alcohol or a mixture of alcohol and water by the usual process of percolation.
Type Process B---In this class are included those fluidextracts in which glycerin or an acid is used in the extraction and two menstrua are successively employed. Menstruum I contains the glycerin or acid in definite proportion to the amount of the drug, and Menstruum II, a mixture of alcohol and water intended for completing the exhaustion of the drug.
Type Process C---The process of fractional or divided percolation. This is especially recommended for drugs containing volatile ingredients or constituents injured by exposure to heat. This process may likewise be used as an alternative process in the formulas in which Type Process A is directed.
Type Process D---In this class are included those fluidextracts in which extraction is effected by. infusion and percolation with boiling water, alcohol being added to the concentrated liquid as a preservative.
In the preparation of fluidextracts by either Process A, B, or C, the rate of percolation must be carefully controlled and, for the quantities directed in the formulas of the Pharmacopoeia, the flow should not exceed ten drops per minute until the reserved percolate is collected, and twenty drops per minute thereafter. As a le one thousand grammes of powdered drug may be exhausted by percolation with sufficient menstruum to yield three thousand mils of percolate.
Fluidextracts should be kept in tightly-stoppered containers for one month and then, if perfectly clear, they should be stored in amber-colored bottles protected from sunlight and extremes of temperature. If sedimentation has occurred the clear portion should be decanted, the remainder filtered and the liquids thoroughly mixed before storing.
The percentage of alcohol in fluidextracts made by type processes A, B, or C is variable and always less than that in the menstruum employed, due, among other causes, to loss of alcohol by evaporation during manufacture, to the presence of a variable proportion of water in the air-dried drug, and to the extraction from the drug of its soluble constituents, which also often vary greatly in different lots of the same drug. The percentage of alcohol in the finished product can therefore only be ascertained by an actual determination (see Determination of Alcohol in Official Preparations, Part II, No. 14).
Type Processes
Type Process A---Moisten one thousand grammes of the powdered drug directed with a sufficient quantity of the prescribed menstruum to render it evenly and distinctly damp and to maintain it so, after macerating for six hours in a tightly-covered container. Then pack it in a cylindrical percolator and add enough of the menstruurn 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 slowly, gradually adding more menstruum until the drug is exhausted. Reserve the first eight hundred and fifty mils of the percolate (unless otherwise specified in the formula); recover the alcohol from the remainder and concentrate the residue to a soft extract at a temperature not exceeding 60' C.; dissolve this in the reserved portion, mix thoroughly, and finally add a sufficient quantity of the menstruum to obtain one thousand mils or the volume determined by calculation from the assay.
Type Process B---Moisten one thousand grammes of the powdered drug directed with a sufficient quantity of the prescribed Menstruum I, to render it evenly and distinctly damp and to maintain it so after macerating for six hours in a tightly-covered container. Then pack it in a cylindrical percolator, add the remainder of Menstruum I, and, when this has just disappeared from the surface, gradually add Menstruum II, constantly maintaining a stratum of liquid above the drug. When the liquid begins to drop from the percolator, close the lower orifice, and, having - closely covered the percolator, macerate for forty-eight hours, and then allow the percolation to proceed slowly, gradually adding Menstruum II until the drug is exhausted. Reserve the first eight hundred and fifty mils of the percolate (unless otherwise specified in the formula); recover the alcohol from the remainder and concentrate the residue to a soft extract at a temperature not exceeding 60' C.; dissolve this in the reserved portion, mix thoroughly, and finally add a sufficient quantity of Menstruum II to obtain one thousand mils, or the volume determined by calculation from the assay.
Type Process C---Divide one thousand grammes of the powdered drug directed into three portions of five hundred grammes, three hundred grammes, and two hundred grammes, respectively. Moisten the first portion of the drug (500 Gm.) with a sufficient quantity of the prescribed menstruum to render it evenly and distinctly damp and to maintain it so after macerating for six hours in a tightly-covered container. Then pack it in a cylindrical percolator and add enough of the menstruurn 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 and then allow the percolation to proceed slowly, gradually adding more of the menstruum. Reserve the, first two hundred mils of percolate and continue the process until the additional percolate measures fifteen hundred mils, the latter being collected in successive portions of three hundred mils each.
Moisten the second portion of the powdered drug (300 Gm.) with a sufficient quantity of the percolate collected in the preceding operation immediately after the reserved portion, to render it evenly and distinctly damp and to maintain it so after macerating for six hours in a tightly covered container. Then pack it in a cylindrical percolator and macerate and percolate as directed for the first part of the drug, using as menstruum the several _portions of percolate from the preceding operation in the order in which they have been collected, and, if this be insufficient, follow with some of the original menstruum. Reserve the first three hundred mils of percolate and continue the process until the additional percolate measures eight hundred mils, collecting e weaker percolate in successive portions of two hundred mils each.
Moisten the third portion of the powdered drug (200 Gm.) with a sufficient quantity of the percolate collected in the preceding operation immediately after the reserved portion, to render it evenly and distinctly damp and to maintain it so after macerating for six hours in a tightly-covered container. Then pack it in a cylindrical percolator and macerate and percolate as before, using as menstruum the several portions of percolate from the preceding operation in the order in which they have been collected, and, if this be insufficient, follow with more of the original menstruum. Collect five hundred mils of percolate and mix this with the two portions previously reserved so as to make one thousand mils of finished fluidextract.
When Type Process C is directed for fluidextracts which are adjusted by assay to a definite alkaloidal standard, collect only four hundred and twenty mils of percolate from the third portion of drug instead of the five hundred mils directed above. Mix this percolate with, the two portions previously reserved, assay a portion of the mixture and then adjust its volume, by the addition of the menstruum directed, so that each one hundred mils of finished fluidextract will contain the prescribed amount of alkaloid.
Type Process D---To one thousand grammes of the ground drug add five thousand mils of boiling water, mix thoroughly and allow it to macerate in a covered container for two hours in a warm place. Then transfer the moist drug to a tinned or enameled metallic percolator and allow percolation to proceed, gradually adding boiling water until the drug is exhausted. Evaporate the percolate on a water bath or steam bath to the volume specified and when cold add the alcohol directed and mix thoroughly.
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