Poly vinyl chloride (PVC) : Less popular in parenteral packaging , PVC is prepared by polymerizing a gas , vinyl chloride or monochloroethylene, in the presence of organic peroxides or inorganic per sulfates as initiators. The length of the molecular chain and the structure of the side chains are altered by the temperature , pressure and the nature of the initiator , PVC’s growth in pharmaceutical packaging is much slower compared with its peers because of environmental concerns . This includes the information of dioxin when PVC is incinerated . Additionally , di(2-ethylhexyl ) phthalate (DEHP) plasticizers are used in the production of many PVC materials. These type of phthalates, which are known to leach out of PVC containers, may have potential health risks. Growth has slowed in this area, which probably reflects preferences for better performing and safer plastics.