Dispendix - Blog

Why Precision in Compound Dilutions Matters for Drug Discovery

Written by Petros Apostolopoulos | Sep 12, 2024 2:30:00 PM

Precise and accurate compound dilutions are essential to experimental outcomes, particularly in drug discovery, where accurate concentrations of test compounds are critical for generating reliable data on the efficacy and toxicity of potential drug candidates1. Even minor inaccuracies in dilutions can skew results, including false positives or negatives and unreliable dose-response data, ultimately delaying drug development.

In this article, we explore the importance of precision in compound dilutions, common challenges, and how automated liquid handling technologies can help researchers overcome these hurdles.

Understanding Compound Dilutions

Compound dilutions involve reducing the concentration of a solution by adding more solvent, typically sterile water or dimethylsulfoxide (DMSO). Types of compound dilution include simple dilutions and serial dilutions. 

  • In a simple dilution, a known volume of a concentrated stock solution is mixed with a specific solvent volume to achieve the desired concentration.
  • A serial dilution involves a stepwise process where each step dilutes the solution further by a constant factor (Fig. 1). This approach is especially prone to error propagation since the accuracy of each dilution depends on the previous sample2.

Figure 1. Serial dilutions involve a stepwise series of dilutions, where the dilution factor stays the same for each step. (Source)

The Role of Precision in Drug Discovery

High-Throughput Screening

In high-throughput screening (HTS), thousands of compounds are tested simultaneously to identify potential drug candidates3. Compound libraries are typically prepared at high concentrations and diluted in a microtiter plate. Precise compound dilutions are essential in minimizing the risk of false positives or false negatives4.

Dose-Response Assays

Once a hit has been identified, researchers must test different compound concentrations to determine its efficacy and toxicity. Researchers use serial dilutions to assess how a drug affects biological targets or cells at various concentrations. These data are used to generate dose-response curves, which are essential for calculating important parameters like IC50 and EC505. Accurate compound dilutions ensure these values are reliable and reproducible, which is crucial when characterizing potential drug candidates.

Consequences of Inaccurate Compound Dilutions

  • False positive or negative results. Inaccurate compound dilutions can lead to false positives or false negatives in hit identification, leading to wasted resources on bad leads (false positives) or potentially effective hits being missed (false negatives)4
  • Inaccurate dose-response curves. Inaccuracies in dose-response curves can lead to imprecise IC50 and EC50 values, resulting in misleading data on a compound’s potency and efficacy5
  • Wasted time and resources. Inaccurate compound dilutions can mean the results of subsequent cell-based assays are meaningless and must be repeated unnecessarily, wasting time and resources and delaying turnaround times4
  • Safety issues. In toxicology testing, over-dilution can mask potential toxic effects, allowing an unsafe compound to advance in drug development. Meanwhile, under-dilution may exaggerate toxicity, causing safe candidates to be discarded prematurely1.

Technologies Enhancing Precision in Compound Dilutions

Understanding the importance of precision in compound dilutions is the first step, but implementing it is far more challenging. Achieving precision in compound dilutions requires a combination of standardized protocols, good laboratory practices, advanced technologies, and regular equipment calibration and maintenance. Automated liquid handling offers several benefits when used in compound dilution workflows: 

  • More precise, accurate dilutions. Automated liquid handling reduces the risk of human error and enhances the accuracy and precision of compound dilutions, supporting the development of safe, effective therapeutics. 
  • Reproducible experiments and reliable data. Automated liquid handlers significantly improve consistency in compound dilutions, minimizing inter-user variability and enhancing the reproducibility and reliability of data from resulting assays. 
  • Enhanced efficiency and higher throughput. Automation enables multiple samples to be processed simultaneously, increasing the throughput of compound dilutions, which is especially important in HTS settings where thousands of compounds need to be diluted and screened in a short time period6.
  • Cost benefits. The reduction in error, combined with reduced labor costs and the potential for miniaturization resulting in lower resource consumption, all contribute to cost reductions in the long run7

The I.DOT Liquid Handler from DISPENDIX can help researchers achieve all these benefits and more when performing compound dilutions. Its DropDetection technology allows for precise, low-volume dispensing down to 0.1 nanoliters (Fig. 2), ideal for miniaturizing assays and reducing reagent waste. Moreover, the I.DOT Liquid Handler’s non-contact dispensing minimizes cross-contamination risks and further ensures consistent and reproducible dilutions. This level of precision and efficiency is crucial in drug discovery, where HTS and dose-response assays require highly accurate compound dilutions to generate reliable data for advancing potential drug candidates6.

Figure 2. DropDetection technology works by identifying changes in light intensity to detect droplets passing the light barrier.

Conclusion

Precise compound dilutions are essential for ensuring reliable, reproducible results in drug discovery, particularly in HTS and dose-response assays. Inaccurate dilutions can lead to costly delays, wasted resources, and compromised data integrity. Automated liquid handling systems, like the I.DOT Non-Contact Dispenser, play a critical role in reducing errors, enhancing efficiency, and maintaining the consistency necessary for advancing potential drug candidates through the drug discovery pipeline.

Discover how the I.DOT Liquid Handler can revolutionize your compound dilutions and streamline your drug discovery process. Download the I.DOT brochure and experience the accuracy and efficiency that sets the I.DOT Non-Contact Dispenser apart!

References

  1. Grant RJ, Roberts K, Pointon C, et al. Achieving Accurate Compound Concentration in Cell-Based Screening: Validation of Acoustic Droplet Ejection Technology. SLAS Discov. 2009;14(5):452-459. doi:10.1177/1087057109336588
  2. Walling LA. An Inline QC Method for Determining Serial Dilution Performance of DMSO-Based Systems. JALA J Assoc Lab Autom. 2011;16(3):235-240. doi:10.1016/j.jala.2011.01.001
  3. Hughes J, Rees S, Kalindjian S, Philpott K. Principles of early drug discovery: Principles of early drug discovery. Br J Pharmacol. 2011;162(6):1239-1249. doi:10.1111/j.1476-5381.2010.01127.x
  4. Burt T, Button K, Thom H, Noveck R, Munafò M. The Burden of the “False‐Negatives” in Clinical Development: Analyses of Current and Alternative Scenarios and Corrective Measures. Clin Transl Sci. 2017;10(6):470-479. doi:10.1111/cts.12478
  5. Calabrese E. The Emergence of the Dose–Response Concept in Biology and Medicine. Int J Mol Sci. 2016;17(12):2034. doi:10.3390/ijms17122034
  6. Schneider G. Automating drug discovery. Nat Rev Drug Discov. 2018;17(2):97-113. doi:10.1038/nrd.2017.232
  7. Holland I, Davies JA. Automation in the Life Science Research Laboratory. Front Bioeng Biotechnol. 2020;8:571777. doi:10.3389/fbioe.2020.571777