Degradation products definition

Even when hydrolysis and epimerization can be avoided during sample preparation and handling, it is not possible to conclude definitively whether the compounds found in plasma and urine are true metabolites or simply degradation products. Indeed, chemical degradation can also occur within the body since urine and plasma contain a wide variety of potential catalysts, including metal ions, phosphate ions, proteins, and sugars (see Sect. 5.2.6). Whereas the existence of mammalian enzymes that act on penicillins and cephalosporins is considered possible [155], no such mammalian enzyme appears to have been identified to date. 

The outcome of planning should include the generation of a method definition requirement document (MDRD) in which all stake holders agree, prior to method development, on the critical attributes of the method. Considerations such as what impurities/degradation products should be monitored, requisite reporting thresholds, the need for an MS-compatible method, if identical methods for DP and DS are required, etc., should be clearly decided and agreed upon by all stakeholders. 

However, a dictionary definition of fouling includes to obstruct (with foreign matter), to entangle, to impede, while a foulant is described as fetid, stinking, and putrid. Thus the definition of foulant should, of necessity, include matter of microbiological origin, plus its degradation products. 

Is an ingredient, inpurity, degradation product, metabolite, or radioactive isotope of a substance described by paragraph (1) of this definition, or some other substance related to a substance described by that paragraph, which is used in the study to assist in characterizing the toxicity, metabolism, or other characteristics of a substance described by that paragraph. 

It is important to remember that stress testing is predictive in nature (as opposed to definitive). That is, the degradation products formed under stress... 

The assessment of degradation in pharmaceutical products involves two aspects of analytical measurement. First, a selective analytical method must be available for accurate assay of the parent drug compound, in order to correctly measure any loss. Second, methodology should be in place for quantification of the degradation products formed. Ideally, when degradation occurs, the measured amount of parent drug lost should correlate well with the measured increase in degradation products. This correlation is referred to as mass balance )- More recently, the International Conference on Harmonization (ICH) has provided a definition of mass balance material balance as follows ... 

For the purposes of this discussion, then, the following definitions will be used (examples are given below the set of definitions). Let P be the parent drug and I be the impurity or degradation product. Assume that MP0 and MPx are the mass of parent compound (and other starting reactants) initially and at time X, respectively MI>0 and Mi x are the total mass of impurities initially and at time X, respectively. Similarly, APj0, NP>X, N o, and Ntx are the analogous number of moles of each. 

Definition The specificity of an analytical method is its ability to measure, both accurately and specifically, the analyte in the presence of components that may be expected to be present in the sample matrix. Specificity may often be expressed as the degree of bias of test results obtained by analysis of samples containing added impurities, degradation products, or related chemical compounds when compared with test results from samples without added substances. The bias may be expressed as the difference in assay results between the two groups of samples. Specificity is a measure of the degree of interference (or absence thereof) in the analysis of complex sample mixtures. 

Definition Limit of quantitation is a parameter of quantitative assays for low levels of compounds in sample matrices, such as impurities and degradation products in food additives and processing aids. It is the lowest concentration of analyte in a sample that can be determined with acceptable precision and accuracy under the stated experimental conditions. The limit of quantitation is expressed as the concentration of analyte (e.g., percentage, milligram per kilogram, parts per billion) in the sample. 

In his introduction to the Lehrbuch, Heuser states objectively Even the methods of treatment adopted by Schwalbe and by Heuser seem to be fundamentally unprofitable, because they do not lead to definite results. These authors have divided the subject along the lines of the various derivatives of cellulose, such as cellulose hydrate, hydrocellulose, oxycellulose, etc. Such discussions are of little value because the substances to which the above names have been applied are not homogeneous chemical individuals, but are mixtures of the most varied degradation products of cellulose and may react very differently under apparently similar conditions. Cross and Bevan have also made the same unfruitful and dangerous mistake of trying to build a system of cellulose chemistry on the basis of such mixtures.. . ... 

This discussion merely provides an indication of the various possibilities. It is not considered appropriate to favor one of the pathways over the others in the absence of definite information. In fact, under conditions in which the molecule is physically torn into pieces, it is very probable that more than one mechanism or set of reactions could be involved, thus providing the multitude of degradation products. 

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