Supersedes the XI Monograph of the State Pharmacopoeia
Extracts are concentrated extracts from medicinal herbal substance, less often from raw materials of animal origin.
By consistency there are the following extracts:
- dry extracts (Extracta sicca);
- soft extracts (Extracta spissa);
- fluid extracts (Extracta fluida).
Dry extracts are powdery mass having the property of flowability, with a moisture content of not more than 5%.
Soft extracts are viscous mass with a moisture content of not more than 25%.
Fluid extracts are thick, mobile, sometimes oily liquids.
Extracts and concentrates are extracts of different consistency, standardized with respect to medicinal herbal medicinal raw materials in certain proportions, for example 1: 1 or 1: 2. These extracts are commonly used to produce infusions and decoctions, replacing medicinal herbal substance in specified proportion.
For the convenience of administration, producing solutions of soft extracts is approved in proportion 1: 2 to original extract. The solvent used is a mixture consisting of 6 parts of purified water, 3 parts of glycerin and 1 part of ethyl alcohol. The shelf life of such a solution should not exceed 15 days.
By the extracting solvent used there are the following extracts:
- aqueous extracts produced using purified water as an extracting solvent;
- alcoholic extracts produced using ethyl alcohol of various concentrations as an extracting solvent;
- oily extracts produced using oil as an extracting solvent;
- extracts produced using various organic solvents (carbon tetrachloride, dichloroethane, etc.);
- extracts produced by sequential extraction of medicinal herbal substance by extracting solvents, including those of different polarities.
According to route of administration, extracts are distinguished:
- for oral administration;
- for topical application.
Soft and dry extracts are used as a substance for production of various medicinal products, fluid extracts can be used for production of medicinal product and directly as a medicinal product.
Medicinal herbal substance, the quality of which meets the requirements of monographs or regulatory documentation, and the corresponding extracting solvents are used to produce extracts.
As one of the evaluation criteria of extraction process efficiency, an indicator such as “Extractives”, the determination of which in medicinal herbal substance is carried out in accordance with the requirements of the GM “Determination of the content of extractives in medicinal herbal substance and herbal medicines”, can be used.
Extracts can be manufactured by percolation, repercolation, maceration, circulation extraction, and other suitable validated methods.
Fluid extracts after completion of the extraction process should be surely maintained at a temperature of 8 – 10 °C for at least 2 days to precipitate the ballast substances that are separated by filtration and to obtain clear liquid.
During the storage of fluid extracts, insignificant precipitate of ballast substances is permitted, provided that there are no biologically active substances in it.
When producing dry and soft extracts, they are released from ballast substances by adding ethyl alcohol, adsorbents to the resulting extract, boiling the extract and other conventional methods, followed by filtration.
The purified extracts are concentrated by vacuum evaporation to the desired consistency (soft extracts).
Dry extracts are produced by drying soft extracts or directly from purified extracts using methods that ensure maximum preservation of active ingredients: spraying, lyophilization, sublimation, etc.
When producing extract-concentrates, they are diluted to the desired active ingredient content using dextrin and other excipients.
Hygroscopicity of dry extracts is reduced by adding lactose, aerosil and other excipients to them.
Description. The color and odor of the extract are specified, if any. If necessary, the presence of opalescence, the possibility of precipitate formation during storage, etc. are specified for fluid extracts.
Loss on drying. For dry and soft extracts, loss on drying is specified in accordance with
the requirements of the GM “Loss on drying”.
Ethyl alcohol. For alcohol-containing extracts, the determination of ethyl alcohol is carried out in accordance with the requirements of the GM “Determination of ethyl alcohol in liquid pharmaceutical products”.
Bulk volume and granulometric composition. Dry extracts are monitored by the indicator “Bulk volume” in accordance with the requirements of the GM “Flowability degree of powders”, and also, if provided by the monograph or regulatory documentation, according to the “Granulometric composition” parameter in accordance with the requirements of the GM “Sieve test”. Standards are specified in the relevant monographs or regulatory documentation.
Heavy metals. All extracts should comply with the requirements for the content of heavy metals – not more than 0.01%, unless otherwise specified in the monograph or regulatory documentation. The determination is carried out in accordance with the GM “Heavy metals”.
Dry residue. For fluid extracts, dry residue is determined by the following procedure: 5.0 ml of fluid extract is placed in a weighing cup, evaporated in a water bath and dried for 3 hours at (102.5 ± 2.5) °C, then cooled in a desiccator for 30 minutes and weighed. Dry residue amount should correspond to the requirements specified in the monograph or regulatory documentation.
Acid value, peroxide value, iodine value, saponification value. If specified in the monograph or regulatory documentation, for oily extracts, the acid value, peroxide value, iodine value, saponification value are determined in accordance with the requirements of the relevant GM.
Density. For oily extracts, density is determined in accordance with the requirements of the GM “Density”.
Solubility. If specified in the monograph or regulatory documentation, for oily extracts, solubility is determined in accordance with the requirements of the GM “Solubility”.
Refractive index. If specified in the monograph or regulatory documentation, for oily extracts, refractive index is determined in accordance with the requirements of the GM “Refractometry”.
Residual organic solvents. In case of using organic solvents in the production of extracts, their residual content is monitored in accordance with the requirements of the GM “Residual Organic Solvents”.
Minimum fill. By minimum fill, extracts should comply with the requirements of the GM “Minimum fill”.
In accordance with the requirements of the GM “Dosage forms”. In a package providing protection from light, unless otherwise specified in the monograph or regulatory documentation.
In accordance with the requirements of the GM “Dosage forms”. For fluid extracts, if there is a possibility of sediment formation (during storage), the label states “Formation of sediment is possible”, “Shake before use”.
In accordance with the requirements of the GM “Storage of medicinal products”. In a dark place at a temperature of 15 to 25 °С, unless otherwise specified in the monograph or regulatory documentation.