Quantitative test, active substance

Validation parameter Confirmation of the identity of pure substances Determination of identity of unknown substances Amount single pure substance Amount active substance Limit test (semi- quantitiative) Amount impurities/ degradation products (quantitative) Dissolution speed of substances Bioequivalence studies... 

Assay, i.e., quantitative tests of the active moiety in samples of drug substance or drug product or other selected component(s) in the drug product. 

The most versatile method for quantitatively determining copovidone is probably the photometric measurement of the iodine complex described in Section 4.3.I.2. It has been successfully tested on samples that also contained a series of auxiliaries and active substances, to verify its suitability for preparations. 

The control tests on the finished product should allow the qualitative and quantitative determination of the composition of the active substance(s). A specification should be provided and this may include the use of markers where constituents with known therapeutic activity are unknown. In the case of herbal substances or herbal preparations with constituents of known therapeutic activity, these constituents should be specified and quantitatively determined. For traditional herbal medicinal products for human use containing vitamins and/or minerals, the vitamins and/or minerals should also be specified and quantitatively determined. 

Quantitative test for the active substance. This describes a situation where there is a requirement to assess how much of a substance is present in a mixture. It may be necessary to quantify several different substances within the same sample mixture. An example of this would be an unknown powder thought to contain both heroin and codeine. 

Another approach is needed for procedures for the determination of impurities in active substances and excipients or degradation products in finished pharmaceutical products. These procedures may include quantitative assays as well as limit tests. Impurities of interest are various, including metals such as lead and other inorganic substances, catalysts, genotoxic impurities, residual solvents etc. Details can be found in the scientific guidelines on e.g. quality from EMA [22], see also Sect. 22.4.2. 

Which performance criteria have to be evaluated depends also on the purpose of the method. Different ICFI/USP guidelines are set up for (1) identification tests, (2) impurity tests, and (3) assay tests. An identification test ensures the identity of an analyte in a sample by comparison to a known reference material. An impurity test is intended to confirm the identity of (limit impurity test) or to accurately quantify (quantitative impurity test) an impurity, defined as an entity which may normally not be present. An assay test finally implies the major component or active ingredient in a sample and quantifies the drug substance as such as a whole or the drug substance in a drug product. 

Since one of the main aims of green chemistry is to reduce the use and/or production of toxic chemicals, it is important for practitioners to be able to make informed decisions about the inherent toxicity of a compound. Where sufficient ecotoxicological data have been generated and risk assessments performed, this can allow for the selection of less toxic options, such as in the case of some surfactants and solvents [94, 95]. When toxicological data are limited, for example, in the development of new pharmaceuticals (see Section 15.4.3) or other consumer products, there are several ways in which information available from other chemicals may be helpful to estimate effect measures for a compound where data are lacking. Of these, the most likely to be used are the structure-activity relationships (SARs, or QSARs when they are quantitative). These relationships are also used to predict chemical properties and behavior (see Chapter 16). There often are similarities in toxicity between chemicals that have related structures and/or functional subunits. Such relationships can be seen in the progressive change in toxicity and are described in QSARs. When several chemicals with similar structures have been tested, the measured effects can be mathematically related to chemical structure [96-98] and QSAR models used to predict the toxicity of substances with similar structure. Any new chemicals that have similar structures can then be assumed to elicit similar responses. 

An unknown substance, X, was isolated from rabbit muscle. Its structure was determined from the following observations and experiments. Qualitative analysis showed that X was composed entirely of C, H, and 0. A weighed sample of X was completely oxidized, and the H20 and C02 produced were measured this quantitative analysis revealed that X contained 40.00% C, 6.71% H, and 53.29% O by weight. The molecular mass of X, determined by mass spectrometry, was 90.00 u (atomic mass units see Box 1-1). Infrared spectroscopy showed that X contained one double bond. X dissolved readily in water to give an acidic solution the solution demonstrated optical activity when tested in a polarimeter. 

Qualitative chemistry is an area of chemistry concerned with identifying substances. In Activity 9.1 you will perform a qualitative analysis to detect the presence of certain ions that, in turn, may reveal an art forgery. The ions could come from paints that were not available at the time of the artwork. In this qualitative analysis, metal ions (cations) and nonmetal ions (anions) are reacted with solvents and with each other. Then the cations and anions present are identified by the products produced. In addition, flame tests and pH determinations are used to identify ions. Qualitative analysis is an engaging opportunity for you to develop experience with chemical change and review solubility principles. Nowadays, however, most of the time a chemist analyzes a substance to detect ion content using quantitative analytical computerized instruments. 

The four most common types of analytical procedures are identification tests, including quantitative measurements for impurities, content, limit tests for the control of impurities, and quantitative measure of the active component or other selected components in the drug substance [18]. Table 1.3 describes the performance characteristics that should be evaluated for the common types of analytical procedures [18]. 

In particular for human toxicity, information shall be generated whenever possible by means other than vertebrate animal tests, through the use of alternative methods, for example, in vitro methods or qualitative or quantitative structure-activity relationship models or from information from structurally related substances (grouping or read-across). 

In a small mortar cooled to OM C, triturate carefully a quantity of the substance to be examined equivalent to about 2500 Ell. Eur, U. of lipolytic activity with 1 mL of cooled maleate buffer solution pH 7.0 R (lipase advent) until a very fine suspension is obtained. Dilute the suspension with cold maleate buffer solution pH 7.0 R. transfer quantitatively to a volumetric flask, and dilute to 100-0 mL with the cold buffer solution. Keep the flask containing the test suspension in iced water during the titration. 

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