D.6 Environmental impact of some medications

Medicinal waste and the environment

  • For many years environmental impact of medicine has been ignored
  • Pharmacologically active compounds (PACs) used in medicine and biochemical studies have not been treated as toxic and have been released into environment. However, prolonged exposure to PAC causes significant change in metabolism of organisms
  • Another pollutant is radioactive materials which is harmful to environment despite its low activity
  • Increasing exposure to radiation can cause apoptosis (programmed cell death) in lymphocytes (white blood cells), untimely reducing immune response and increasing risk of contracting diseases
  • Nuclear waste increases probability of developing cancer, birth defects, reproductive disorders and weak immune system

Antibiotic resistance

  • Widespread use of penicillin and other antibiotics have led to development of antibiotic resistance in bacteria
  • As a result, bacteria are resistant, so scientist make new drugs to combat this, but over time, bacteria become resistant to those as well
  • Factors causing antibiotic resistance
    • Over-prescription of antibacterial
    • Non-compliance of patients
    • Use of antibacterial in agriculture (Given to animals prevent disease, promote livestock growth)
      • This method causes fastest antibacterial resistance because it gets into environment and humans, giving time for bacteria to resist its effects
    • Release of antibacterial waste by hospitals
  • Since 1990’s use of antibiotics have been mostly banned and are now only used for the most severe bacterial infections to prevent bacterial resistance

Nuclear Waste

  • Many medicinal procedures involve use of radionuclides which are unstable isotopes of certain elements that undergo spontaneous radioactive decay
  • When radionuclides come into contact with various materials, those irradiated materials and the radionuclides are described as nuclear waste
  • Low level waste: waste that gives off small amounts of ionizing radiation for a short time
    • Caused by radionuclides used in hospitals due to low activity and short half-life decay
    • The major radionuclides used for radiotherapy are also included in LLW
  • High level waste: waste that gives off large amounts of ionizing radiation for a long time
    • Caused by nuclear reactors and contains products of nuclear fission. Have long half-life decay and require proper treatment and storage underground to prevent radiation damage
  • Effects of antibacterial and radioactive waste can be cumulative. It is best to dispose of each type of waste in their respective ways to prevent potential hazard from combined effects

Waste from pharmaceutical industry

  • Most of the waste is organic compounds
  • Chlorinated solvents ( CHCl3, CCl4, CH2Cl2) present the hazard of causing ozone depletion and contribute to formation of “photochemical smog”
  • The disposal of chlorinated solvents is an expensive and complex process. Hard for industry to pay for that

Green Chemistry

  • Efficiency of a reaction in regular chemistry is measured in terms of product yield and cost of raw materials
  • Green chemistry focuses on reducing environmental impact by minimizing use of hazardous materials
  • Another important focus is the use of biotechnologies in organic synthesis
  • Shikimic acid is a precursor to the antiviral drug oseltamivir (Tamiflu)
    • For many years shikmic acid was extracted from a natural source however, outbreak of bird flu in 2005 resulted in increased demand of oseltamivir, and thus shikimic. Green scientists then produce shikimic acid from E. coli effectively presenting shortages of oseltamivir in future
  • Industrial use of natural products leads to issues:
    • Extinction of plant species
    • Rising food prices

The Atom Economy

  • Is a measure of the amount of starting materials that become useful products.
  • High atom economy means that less waste is created and reaction has a high efficiency

Atom Economy

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