Two computer programs using logit transformation for the analysis of S-shaped curves

Area of Science:

• Pharmacology
• Biostatistics
• Computational Biology

Background:

• S-shaped curves are common in dose-response relationships and biological assays.
• Probit analysis is a standard method for analyzing such data but can be computationally intensive.
• Limited computing memory or the need for faster calculations can be a barrier to using probit analysis.

Purpose of the Study:

• To present two BASIC computer programs for the analysis of S-shaped curves.
• To utilize logit transformation as an alternative to probit transformation.
• To provide efficient computational tools for biological and pharmacological data analysis.

Main Methods:

• Development of two BASIC computer programs.
• Application of logit transformation for S-shaped curve analysis.
• Estimation of median effective dose (ED50) using a maximum likelihood method.
• Fitting S-shaped curves to empirical data not easily transformed to proportions.

Main Results:

• The first program accurately estimates the median effective dose (ED50) of drugs.
• The second program effectively fits S-shaped curves to complex empirical data.
• Logit transformation demonstrated to be a viable and efficient alternative to probit transformation.

Conclusions:

• Logit transformation provides a simple and accurate method for analyzing S-shaped curves.
• The developed BASIC programs are suitable for situations with limited computing memory or when calculation speed is critical.
• These tools can enhance the accessibility and efficiency of dose-response analysis in various scientific fields.