Dose-Response Relationship

Knowledge of the relationships between drug concentration and disease response is important for the safe and effective use of drugs. Creative Biolabs provides you dose-response determination service to help identify a safety dose and give suggests for dosage adjustment according to a particular circumstance.

Studying dose response, and developing dose-response models, is vitally important for determining dosages for drugs. The dose-response relationship describes the change in effect on an organism caused by differing levels of drug doses after a certain exposure time. This work may apply to individuals or populations. Establishing dose-response relationship has a wide range of applications, for example, ascertaining the magnitude of the clinical responses caused by different pharmacokinetic and labeling dosage and administration instructions. The measured dose is generally plotted on the X axis, and the response is plotted on the Y axis.

Figure 1. In vitro concentration-response curve. (Larsen et al. 2005)

IC₅₀

The most commonly used measurement for the dose-response curve is the IC₅₀. Dose-response represents different concentrations of inhibition or mortality activity. IC₅₀ terms half maximal inhibitory concentration, which is the concentration of a drug inducing half inhibition between the baseline and maximum after a specified exposure time. This index is commonly used as a measurement of potency in a drug in pharmacological research. Broth- and agar-based assay can be used to determine the dose response curve and IC₅₀.

Dose-Response and Drug Combination

In addition to determining a single drug's dose-response curve, Creative Biolabs creates models of dose-response for 2 or more combined drugs to evaluate the efficacy of combined compounds against diseases. Generally speaking, drug interaction in vitro would possibly produce 3 different categories of effects: synergism, antagonism, and indifferent effects. Especially for synergism effect, it is an effect arising between two or more agents that produces an effect greater than the sum of their individual effects. It allows the use of smaller amounts of drugs to treat serious diseases.

Methods for Statistical Analysis of Dose-Response Curve

Creative Biolabs established models of the quantitative in vitro response and drug concentrations by using local nonparametric regression methods, including probit model, logit model, and Spearman-Karber method. Dose-response relationship and the in vitro drug susceptibility test provide reliable models to predict the murine response to drugs. Dose-response curves are generally sigmoidal and monophasic. We can transform and linearize the dose-response relationship data by several models, like empirical models, based on nonlinear regression, which is easily for analysis.

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Reference

1. Larsen R A, Bauer M, Thomas A M, et al. (2005). "Correspondence of In Vitro and In Vivo Fluconazole Dose-Response Curves for Cryptococcus neoformans." Antimicrob Agents Chemother 49(8): 3297-3301.

For Research Use Only.