Propylene glycol market, widely used as a pharmaceutical excipient, has come under increased regulatory scrutiny due to safety, quality, and compliance concerns highlighted by both regulatory agencies and global health organizations. As a critical component in oral liquid medicines and over-the-counter (OTC) formulations, ensuring its purity and proper testing remains essential to prevent contamination-related risks.
A major regulatory development occurred in April 2025 when the U.S. Food and Drug Administration (FDA) issued a Warning Letter to Dyno Manufacturing Inc. following an inspection conducted between October and November 2024. The agency identified serious Current Good Manufacturing Practice (CGMP) violations, including the company’s failure to perform identity testing on high-risk raw materials such as propylene glycol, glycerin, and ethanol. Instead, the firm relied solely on supplier certificates, despite the known risk of contamination with toxic impurities like diethylene glycol and methanol.
The FDA also cited the absence of a formal stability program, with no stability studies conducted to support product shelf life. Additionally, manufacturing processes for products such as hand sanitizers and antibacterial soaps were not validated, and there was no cleaning validation to prevent cross-contamination. The company’s Quality Unit was found to be inadequate, lacking proper oversight, written procedures, annual product reviews, and controls to ensure data integrity. The FDA urged immediate corrective measures and recommended engaging a qualified GMP consultant, warning that continued non-compliance could result in further regulatory action.
Parallel to FDA findings, the World Health Organization (WHO) issued a Medical Product Alert (No. 4/2024) regarding falsified USP/EP grade propylene glycol identified in Pakistan. The alert highlighted the detection of multiple batches falsely labeled as DOW-manufactured propylene glycol, which were later confirmed to be counterfeit. These materials were found to be contaminated with harmful substances such as ethylene glycol and diethylene glycol—chemicals known to cause serious toxicity when ingested.
The situation escalated as the Drug Regulatory Authority of Pakistan (DRAP) issued rapid alerts in August and September 2024 after linking the falsified propylene glycol to contaminated oral liquid medicines. Laboratory analysis confirmed contamination levels, including ethylene glycol at measurable concentrations, raising serious concerns about patient safety. The falsified products were deliberately misrepresented, including fake certificates of analysis, making detection more difficult and increasing the risk of distribution through informal supply chains and online markets.
These developments align with earlier regulatory guidance issued by the FDA in May 2023, which emphasized the need for stringent testing of high-risk excipients—including propylene glycol, glycerin, and sorbitol solutions—for contamination with diethylene glycol and ethylene glycol. This guidance was introduced in response to multiple global incidents of contaminated pharmaceutical products, particularly affecting pediatric and oral liquid formulations.
Overall, the propylene glycol market is facing intensified scrutiny due to rising concerns over contamination, falsification, and inadequate manufacturing controls. These incidents underscore the critical importance of rigorous testing, validated processes, and strong regulatory compliance frameworks. As global health authorities continue to strengthen oversight, pharmaceutical manufacturers are expected to adopt stricter quality assurance practices to ensure the safety and reliability of excipients used in drug formulations.
