Leaching of plastic polymers by plastic vials used for storing homoeopathic medicines: A preliminary study

Background: In Homoeopathy, plastic containers/vials are used for the storing/dispensing of ethanol-based medicines instead of glass. Various studies have suggested that plastic components that leach out in stored substances tend to cause contamination and may produce adverse effects in living systems. The present study was aimed to find out chemical composition and leaching behaviour of commonly used plastic vials (PVs) if any during the storage of ethanol-based homoeopathic medicines in optimal environment. Material and Methods: The experiments were conducted on two sample sets of PVs. Chemical properties of PV were assessed by Fourier Transform Infrared Attenuated Total Reflectance (FTIR-ATR) spectroscopy. PV were cut separately [sample-1 (S-1) and sample-2 (S-2)] and immersed in Homoeopathic Grade Ethanol (HGE) in conical flask and stored for 7 days at ambient temperature (25° ± 5C) with constant rotary shaking. After 7 days, S-1 and S-2 of PV in Homoeopathic Grade Ethanol (HGE) were decanted and filtered. Aliquots (A1 and A2) were analysed by proton nuclear magnetic resonance spectroscopy (H 1 NMR). The spectral graph obtained by FTIR-ATR spectroscopy for PV compositions and spectral graph obtained by H 1 NMR spectroscopy for PV ethanol aliquots were examined for PVs material and PV leaching effect in HGE. Results: FTIR-ATR spectra showed that PV are made up of two types of polyolefin's compounds i.e. Low Density Polyethylene (LDPE) and Linear Low Density Polyethylene (LLDPE). Aliquots of PV in HGE showed the presence benzophenone and its methyl derivative, heat and light stabiliser (2, 2, 6, 6-tetramethylpiperidine and amino derivative), antioxidant (4, 4'- thiobis and 2-tertbutyl-5-methylphenol) and plasticizer bis 2-Diethylhexyl phthalate (DEHP) or Dioctyl phthalate (DOP). Results of study suggest that PVs leach out plastic polymers in HGE. Conclusion: This preliminary experiment suggests that it is not safe to use LDPE/LLDPE plastic for storing/dispensing ethanol based homoeopathic medicines. Further study with other grades of plastic is desirable.