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Pharmaceutical packaging industry required $20 billion a year by 2013 and will expect to rise up to $78.79 billion by 2018. Among them, 80% of pills in the world are packed with blister packaging, which is the most convenient type for several reasons. Blister packs have two main components, the “lid” and the “blister” (cavity). Lid is mainly manufactured with aluminum (Al) and paper. The Cavity consists of polyvinyl chloride (PVC), polypropylene (PP), polyester (PET) or aluminum (Al).〔 If users employ proper disposal methods, all these materials can be recycled and the harmful effects to the environment can be minimized. However, a problem arises with the improper disposal either by burning or disposing as normal household waste. Burning of blister packs directly causes air pollution by the combustion products of polypropylene (()n), polyester (()n), and polyvinyl chloride (()n). The combustion reactions and products of these chemicals are mentioned below. ()n + 9n/2 O2 → 3n CO2 +3n H2O ()n + 10n O2 → 10n CO2 +4n H2O ()n + 2n O2 → n CO2 + n H2O + n HCl + n CO The products, carbon dioxide (CO2) and water vapor (H2O) act as primary greenhouse gases which can lead to the greenhouse effect that causes global warming ultimately. Even though polypropylene and polyester is harmful to the environment, the most toxic effect is due to the combustion of polyvinyl chloride since it produces hydrochloric acid (HCl) which is an irritant in the lower and upper respiratory tract that can cause adverse to human beings. Moreover, carbon monoxide (CO) can cause oxygen deficiency in tissues by binding to hemoglobin with 200-250 times higher affinity than the oxygen, which leads to unconsciousness or death by suffocation. The disposal of blister packs as normal waste, will forbid recycling process and eventually accumulate in soil or water, which will result soil and water pollution since bio-degradation processes of compounds like PVC, PP and PET are very slow. As a result, ecologically damaging effects like disturbances of the habitats and movements can be seen. Ingestion by the animals, affect the secretion of gastric enzymes and steroid hormones that can decrease the feeding stimuli and may also cause problems in reproduction. At low pH, aluminum can increase its solubility according to the following equation. As a result, the negative effects of both aquatic and terrestrial ecosystems can be generated. 2Al(s)+ 6H+ → 2Al3+ (aq) + 3H2 (g) In aquatic ecosystems, aluminum ions (Al3+) act as a toxic agent for gill breathing animals like invertebrates and fish by reducing the activity of gill enzymes which can result the reduction of active uptake of ions. In terrestrial systems, the metabolic processes of mammals and birds can be disturbed by digestion of Al compounds. Moreover, aluminum can accumulate in plants and can affect their nutrient uptake. Both invertebrates and plants accumulate Al, which can enter into the terrestrial food chains.〔 By employing proper disposal methods, all manufacturing materials of blister packs like PP, PE, PVC and Al can be recycled and the adverse effects to the environment can be minimized. Even though, the synthesis of these polymers relatively simple, the recycling process can be very complex since the blister packs contain metal n(CH2=CHCl ) → (CH2=CHCl )n The mechanism of nitroxide (-NOR2) mediated controlled free radical polymerization for PVC is mentioned below as an example of polymer synthesis. Here, the starting material can produce two free radicals due to experimental conditions. Then, by adding vinyl chloride monomers to the growing polymer chain will produce PVC as the product. As the first step of recycling, separation of Al and Polymers using the hydrometallurgical method which uses hydrochloric acid (HCl) 〔 can be incorporated. Then PVC can be recycled by using mechanical or chemical methods. The most recent trend is to use biodegradable, eco-friendly “bio plastics” which are also called as biopolymers such as derivatives of starch, cellulose, protein, chitin and xylan for pharmaceutical packaging, to reduce the hostile effects to the environment.〔 == References == 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Environmental impacts from disposal of pharmaceutical packaging of pills」の詳細全文を読む スポンサード リンク
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