Determination of potency

For the determination of potency assay of a drug substance or a drug product, the usual range of linearity should be +20% of the target or nominal concentration. For the determination of content uniformity, it should be 30% of the target or nominal concentration. Figure 3 illustrates the linearity of a sample set of data. 

The structme-activity studies with diclofenac and lumiracoxib reveal that the COX-2 inhibitory activity of lumiracoxib results from a fine balance between potency and selectivity. The principal determinant of potency is the dUialoarylamine ring, whereas the raefa-methylarylacetic acid ring primarily controls selectivity. An F— C1 substitution in the dihaloarylamine ring of lumiracoxib increases the tightness of binding (potency of... 

Staphylococcus aureus 6538P for the determination of potency of potassium phenoxymethyl penicillin. The aureus 6538P strain is the same as S. aureus 209P. 

Zhu J, Lou L-Y, Li J-G, Chen C, Liu-Chen L-Y (1997) Activation of the cloned human kappa opioid receptor by agonists enhances [35S]GTPyS binding to membranes determination of potencies and efficacies of ligands. J Pharmacol Exp Ther 282 676-684... 

The two types of sensations, trigeminal and olfactory, can be separated by making use of anosmics (persons who lack the sense of smell) as compared with persons with normal olfaction and nasal irritation. To determine the relevant physio chemical determinants of potency, these two groups of persons were exposed to single chemicals [14]. The study showed that a general relationship between odour and irritation thresholds might be present. It was found that the threshold level (odour/irritation) decreases as the length of the carbon chain increases. 

Thorpe R, Wadhwa M, Page C, Mire-Sluis A. Bioassays for the characterisation and control of therapeutic cytokines determination of potency. In Brown F, Mire-Sluis AR, eds. Biological Characterization and Assay of Cytokines and Growth Factors. Dev Biol Stand. Basel Karger, 1999 97 61-71. 

Rezapkin G, Dragunsky E, Chumakov K. Improved ELISA test for the determination of potency of Inactivated Poliovirus Vaccine (IPV). Biologicals 2005 33 17-27. 

For the determination of potency of tyrothricin the turbidimetric assay method, with Streptococcus faecalis group D) strain M 19 (ATCC 10 541) as test organism, is used. The reference standard is a mixture of 20 per cent crystalline gramicidin and 80 per cent crystalline tyrocidine hydrochloride . ... 

Resistance to bacitracin does not emerge rapidly in originally susceptible strains. The thermal and storage stability of bacitracin is enhanced by the presence of an equimolar concentration of Zn " and the antibacterial action is potentiated by an excess of Zn " ". It has been suggested that Zn + is also associated with the mechanism of antibacterial action. No chemical assay methods are yet available for bacitracin. For the determination of potency the cylinder plate method with Micrococcus flavus (ATCC 10 240) as test organism is used. ... 

No chemical methods for assaying either polymyxin or colistin are available at the present time. For the determination of potency either the cylinder plate assay using Brucella bronchiseptica ATCC 4617 as test organism or the nephelometric method is used. The current USP standards are 7,850 units/mg for polymyxin B and 20,070 units/mg for colistin. 

Longobardo M, Delpon E, Caballero R, et al. Structural determinants of potency and... 

Knudson (1950) has outlined some of the characteristics of microbiological assays for the determination of potency of a preparation for several types of response including expressions appropriate for linearization of the dosage-response curves, calculation of the slope, and also the errors. 

A microbiological method (see p. 813) is prescribed by the B,P. although the U,S,P. XV (for oxytetracycline itself) relied on a version of the colorimetric method with ferric chloride (see below). The microbiological determination of potency in the B,P. is augmented by a spectrophoto-metric assay ... 

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