Drugs purity

Packages, packaging machinery, and workplace from viewpoint of their effect on food and drug purity package labeling and marking. 

Stalberg, O., Westerlund, D., Hultin, U. K., and Schmidt, S. (1997). Improvements in drug purity determination by capillary electrophoresis using UV-absorption and LIF-detection with a UV-laser. Chromatographia 44, 355—361. 

S.-O. Janson, Characterization of drug purity by liquid chromatography, J. Pharm. Biomed. Anal., 4 615 (1986). 

P. F. Vanbel, J. A. Gilliard, and B. Tiliquin, Chemometric optimization in drug analysis by HPLC a critical evaluation of the quality criteria used in the analysis of drug purity, Chromatographia, 36 120 (1993). 

If we apply this approach to the drug purity problem, in a long series of instances there will be three types of outcome. The true drug content may be ... 

The use of UV-vis and FT-IR spectroscopy in determining drug impurities without previous chromatographic separation is limited because of the low selectivity of both methods. In some cases, when the impurity has spectral properties that are very different from those of the active substance, the direct measurement of absorbance can give some useful data about the structure of the impurity. But, in many cases the impurity has a similar structure to the active substance and, therefore, their UV and IR absorption spectra are similar, and overlap with each other additively. This means that direct use of spectroscopic methods in drug purity analysis is limited [49]. 

Selectivity of the UV method can be increased by the use of spectra derivatives [50]. Derivative spectrophotometry is a chemometric method in which classic UV spectra (zero-order spectra) are differentiated with respect to wavelength before being analyzed. It is much more selective and precise than classic UV spectroscopy [50]. Examples of the use of the spectra derivatives method in drug purity analysis are shown in Table 8.4. 

Calculations of drug purity using DSC were used to assess the quality of progesterone and lipoic acid, and to define specifications for the drugs. The enantiomeric purity of (-)ephedrinum 2-naphthalenesulfonate has also been determined using DSC. ... 

A manufacturer may use his own standard instead of an official standard but in this case there are requirements that have to be met such as the submission of the details of the standard and method of analysis used. The standard must meet two criteria it must ensure the highest degree of drug purity and the least variation on potency. 

Diding, E., Sandstrom, H., Ostelius, J., Karlen, B. and Bogentoft, C. Studies on the application of integrated gas chromatography-mass spectrometry in drug purity control. Impurities in clofibrate, norethindrone, methandienone, haloperidol and meladrazine. Acta Pharm. Suec. 13 55-64, 1976. 

Before we consider topics such as the design of an assay, calculation of drug purity, and so on, it is useful to revise the units and terms chemists use for amount of substance and concentration. The fundamental unit of quantity or amount of substance used in chemistry is the mole. The mole is the amount of a substance (either elements or compounds) that contains the same number of atoms or molecules as there are in 12.0000 g of carbon-12. This number is known as the Avogadro number (after Amedeo Avogadro, an Italian chemist) or Avogadro s constant, and has the value 6.02 X 1023. When this amount of substance is dissolved in solvent (usually water) and made up to 1 litre, a 1 molar (1 m) solution is produced. In a similar way, if one mole of substance were made up to 2 litres of solvent, a 0.5 m solution would result, and so on. The litre is not the SI unit of volume but, along with the millilitre (mL), is still used in the British Pharmacopoeia. 

PEGylation—Increased potency of a protein, improved stability, compatibility, and higher bulk drug purity. 

Krstulovic, A. M. and Lee, C. R. Defining drug purity through chromatographic and related methods current status and perspectives. J. Chrom. B. 689(1) 137-153, 1997. 

APPLICATION OF CHEMOMETRIC METHODS IN DRUG PURITY DETERMINATION BY CAPILLARY ELECTROPHORESIS... 

Applications of chemometric methods in drug purity determination 97... 

In drug purity analysis when several (closely related) compounds have to be separated, the methods have to be optimized with regard to multiple criteria, including the resolution between analytes that react sensitively to changes of the experimental conditions (so-called critical pairs) and/or analysis time. Sometimes, multiple critical pairs exist. Thus, experimental design... 

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