The Diethylene Glycol (DEG) Tragedy and Its Impact on Liquid Oral Formulation Regulations in India
The Diethylene Glycol (DEG) poisoning incidents represent one of the most tragic and defining chapters in the history of pharmaceutical formulations, not only in India but globally. Although DEG-related tragedies have occurred worldwide since the 1930s, repeated incidents in India exposed deep systemic weaknesses in excipient control, quality testing, and regulatory oversight of liquid oral formulations such as cough syrups and pediatric medicines.
In multiple documented cases across decades, DEG—an industrial solvent—was inadvertently or fraudulently used as a substitute for pharmaceutical-grade glycerin or propylene glycol in oral liquid formulations. The motivation was simple but devastating: DEG was cheaper, easily available, and visually indistinguishable from approved excipients. When consumed, particularly by children, DEG caused acute renal failure, metabolic acidosis, and death. These incidents revealed that the problem was not limited to one manufacturer or one state, but rather embedded in the way excipients were sourced, tested, and approved.
Judicial scrutiny and expert committee investigations following these incidents highlighted critical regulatory gaps. At the time, excipient manufacturers were largely unregulated, vendor qualification systems were weak, and testing of incoming excipients by formulation manufacturers was often limited to identity checks rather than impurity profiling. Certificates of Analysis were accepted at face value, with minimal cross-verification. The legal proceedings emphasized that excipients, although pharmacologically inactive, could no longer be treated as low-risk components.
The aftermath of these cases led to a paradigm shift in how liquid oral formulations were regulated in India. The Central Drugs Standard Control Organization (CDSCO) strengthened its stance on excipient control, mandating stricter raw material testing, particularly for glycerin, propylene glycol, and sorbitol. Pharmacopoeial monographs were tightened to include specific tests for DEG and ethylene glycol contamination. Manufacturers were compelled to upgrade their quality control laboratories, adopt risk-based vendor qualification systems, and maintain traceability across the supply chain.
Beyond regulatory amendments, the DEG tragedy reshaped the industry mindset. Quality assurance functions gained prominence, excipient suppliers came under closer scrutiny, and GMP inspections expanded their scope to include excipient management practices. Internationally, these incidents also influenced WHO guidelines on pharmaceutical excipients, reinforcing the idea that patient safety is determined not just by the active ingredient, but by every component in the formulation.
This case fundamentally altered India’s pharmaceutical quality framework. It transformed excipient control from a procedural checkbox into a critical quality and patient-safety function, setting the foundation for modern risk-based GMP systems now followed across the industry.
MBH/PS