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Biological Assays

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Biological Assays

A bioassay or biological assay is a biological testing procedure for estimating the concentration of a pharmaceutically active substance in a formulated product or bulk material. In contrast to common physical or chemical methods, a bioassay results in detailed information on the biological activity of a substance. Over the last decade bioassays and biostatistical analysis have become more important in effectively controling the quality of biopharmaceutical development and manufacturing.

The general approach of most bioassays is to perform a dilution assay, which measures the biological responses at several doses. A key assumption of a dilution assay is that the active component follows the same principle of activity in standard and in sample preparation. In this case the unknown preparation may in theory be derived by diluting it with inert components or by concentrating the bulk solution. This concept of similarity may be monitored by using the parallel-line model (parallel-line assay) or the parallel-logistics models. Additionally, slope-ratio and dichotomous assays (quantal response assays) are available as well.

All methods are suitable for analysing the results obtained by several biological assays. Examples of these assays are given below:

  • Several immunochemical methods
  • Microbiological assay of several antibiotics (diffusion method and turbidimetric method)
  • Assay of human coagulation factor VIII
  • Assay of diphteria vaccine
  • Assay of heparin
  • Assay of pertussis vaccine
  • Assay of tetanus vaccine
  • Assay of human anti-D immunoglobulin
  • Assay for erythropoietin

Biological assays require advanced analysis software, which supports all assay types and complies with the US Pharmacopeia as well as the European Pharmacopoeia. PLA 3.0 is the most advanced software for this task. Over 450 organizations around the world are already using it.

Potency ratio–a brief synopsis

Affiliation

  • 1 Division of Endocrinology, Jewish Hospital of St Louis, MO 63110.
  • PMID: 8495276
  • DOI: 10.1093/rheumatology/32.suppl_2.24

Potency ratio–a brief synopsis

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Author

Affiliation

  • 1 Division of Endocrinology, Jewish Hospital of St Louis, MO 63110.
  • PMID: 8495276
  • DOI: 10.1093/rheumatology/32.suppl_2.24

Abstract

Deflazacort (DFZ) is a novel glucocorticoid with bone sparing properties, and there have been numerous studies investigating its potency relative to other glucocorticoids. As estimates of potency are difficult to evaluate in patients with disease, the concept of minimum effective dose is used. In double-blind, crossover studies, paired patient studies and between-patient studies, the potency of DFZ to prednisone (PDN) and to methylprednisolone was established as being 1.28:1 (1.17-1.38, 95% CI) and 1.6:1 (1.45-1.75, 95% CI), respectively. The bone wasting properties of DFZ have been determined using the concept of bone wasting ratio (ratio between bone loss velocity values observed in patients given the minimum effective doses of two glucocorticoids). The results of three studies which have evaluated the bone wasting ratio of PDN to DFZ indicate that this ratio is approximately 2.03:1 (1.84-2.23, 95% CI). That is, at therapeutically equivalent doses, twice as much bone loss occurs with PDN as with DFZ.

Deflazacort (DFZ) is a novel glucocorticoid with bone sparing properties, and there have been numerous studies investigating its potency relative to other glucocorticoids. As estimates of potency are difficult to evaluate in patients with disease, the concept of minimum effective dose is used. In do …