Green analytical chemistry review calls for integrated sustainability metrics and AI to improve pharmaceutical analysis

A comprehensive review of 20 years of green analytical chemistry has concluded that no existing tool can measure the full environmental, safety and resource footprint of pharmaceutical testing on its own and has called for laboratories to combine several metrics instead

A recent review has traced 20 years of progress in green analytical chemistry and has concluded that no single tool is sufficient to measure how environmentally sound a pharmaceutical testing method really is. The review was carried out by Dr. K. Archana, Dr. M. Sumithra and graduate student G. Vigneshwaran all of the Department of Pharmaceutical Chemistry and Analysis, Vels Institute of Science, Technology and Advanced Studies, Chennai, India. 

The authors examined the tools that laboratories currently use to assess the ‘greenness’ of a given analytical method and argued instead for an integrated, multi-metric approach that covers the full environmental, safety and resource footprint of analytical practice across the pharmaceutical industry.

Every stage of a pharmaceutical product’s life depends on analytical chemistry, from tests on raw ingredients through to quality checks on finished pharmaceutical products. They underpin drug safety, regulatory compliance and the decision to release product batches to market. Yet laboratory practices and many conventional analytical methods have historically been resource-heavy and environmentally costly:

• • rely on large volumes of hazardous organic solvents
  • generate significant quantities of chemical waste
  • consume substantial energy.

For an industry that operates at a global scale and is continuously running these tests, the cumulative environmental impact has the potential to be considerable. Green analytical chemistry (GAC) – a branch of the wider green chemistry framework first articulated by Dr. Paul Anastas in the 1990s – has emerged as the field’s response to this problem. Rather than apply sustainability principles only to the synthesis of chemical compounds, GAC applies them directly to how analytical measurements are designed and carried out.

The central contribution of the review is a structured, critical comparison of the measurement tools developed over the past 20 years to assess the ‘greenness’ of any given analytical methodology. The authors examined established metrics including:

• • US’ National Environmental Methods Index
  • Analytical Eco-Scale developed by Gałuszka et al in 2012 – a solvent-focused tool often referred to as the ‘Green Solvent Selection Tool’
  • Environmental Assessment Tool – a high-performance liquid chromatography test
  • Analytical Method Volume Intensity metric
  • Green Analytical Procedure Index
  • Analytical GREEnness metric,
  • Process Mass Intensity Life Cycle Assessment framework,
  • RGB 12 algorithm – built on the red-green-blue additive colour model
  • Need, Quality and Sustainability Index.

Each tool was assessed on its scope, methodology and usability in a pharmaceutical setting.

The review traced a clear generational shift in how these tools work. Earlier instruments relied primarily on qualitative pictograms: colour-coded visual indicators that flag whether a method uses hazardous reagents or generates problematic waste but offered no numerical basis by which to compare methods.

Second-generation metrics move towards quantitative, multi-criteria scoring frameworks that attempt to weigh environmental impact, analytical performance and operational practicality together on a single scale. While this made them more informative, they were also harder to apply. The authors found that while this evolution represents genuine progress, significant gaps remained. Most current tools provide only partial lifecycle coverage by capturing environmental impacts at certain points in the analytical process but not across its full lifecycle.

Also, there is no standardised scoring convention shared across tools, so the same method can produce different conclusions according to which metric is used to evaluate it, a problem that complicates both regulatory interpretation and comparison between studies. A further limitation the authors identified is the near-absence of digital integration and of computational or machine-learning-enhanced features, which restricts the ability of these tools to support automated method screening or predictive environmental assessment.

The central argument of the review is that the field has reached a point at which reliance on any single metric ‘greenness’ is no longer defensible. Each existing tool captures a different slice of what it means for an analytical method to be sustainable:

• • solvent hazard
  • waste generation
  • energy consumption
  • operator safety

but none covers all of these dimensions comprehensively on its own. The authors proposed that a genuinely robust assessment framework must integrate multiple complementary metrics into a unified toolbox, one able to evaluate analytical sustainability across environmental, occupational safety and resource-efficiency dimensions at the same time. Such an approach, they argued, would produce more reliable and comparable assessments and would give pharmaceutical laboratories a clearer, more actionable picture of where their methods fall short and how to improve them.

For further reading please visit: 10.2174/0129504023449165260615103853