Modification Of The Quality Standard For Propylene Glycol

Abstract:Objectives To provide better technical support for ensuring the controllability and security of the quality for propylene glycol, the quality standard including IR spectra identification, reducing and related substances determination were revised. Methods and Results1. IR spectra identification By examining the sample with different water capacity, the different time of the liquid film exposed in the air and the different drying time of the liquid film under the infrared lamp, the reasons for the appearance of the abnormal peak at1650cm-1in the infrared spectrum were analyzed. It was due to the influences of the sample’s water capacity and the time of the liquid film exposed in the air. By drying the liquid film with infrared lamp for60seconds, the influences of the above were eliminated.2. Examination of the reducing substance Formaldehyde reacted with MBTH can generated triazine Triazine in an acid solution would be oxidized into blue-green compound by ferric ion. The content of aldehydes in1,2-propylene glycol was calculated depending on the Lambert-Beer law. The established method of UV-Vis spectrophotometry was feasible and the limit was set as1μg/g.The content of aldehydes in the samples from rectification had less differences between batches than the content in the samples from activated carbon absorption. So the rectification was steadier than the activated carbon absorption.3. Examination of the related substance GC-MS/MS was selected to make a preliminary analysis of unknown impurities in1,2-propylene glycol. It was confirmed that the unknown impurities was probably the other5isomers of DPG. By statistical analysis of the content and the types of related substances, the diversity between different manufactures and different production processes can be examined. The current standard should include the limit for total impurities and the largest unknown impurity, based on the overall low level of impurities in the samples.The content of impurities in the samples from rectification was less than the content in the samples from activated carbon absorption,so the samples from rectification was better. 4. Determination of the content of1,2-propylene glycol in Vitamin K1injection The established method of GC was feasible.19batches of Vitamin K1injection was determined and the content of1,2-propylene glycol was less than the maximum usage range for intramuscular injection (40.0%) and optional change of accessories was also not found. These samples can be used for injection and the test of bacterial endotoxin, cytotoxincity and other biosafety should be added to the current standard or we should establish the standard for1,2-propylene glycol (for injection and not for injection) in order to eliminate security risks.35charts,27tables,59references...