The document provides an overview of radiopharmaceuticals and radioactivity, including the types of radiation (alpha, beta, and gamma) and their properties. It discusses the half-life of radioactive substances, units of radioactivity, and various pharmaceutical applications, notably in cancer and thyroid treatment. Additionally, it outlines safety precautions for handling radioactive substances and the importance of proper storage and hygiene practices.

1. PT 103 PHARMACEUTICAL INORGANIC
CHEMISTRY(THEORY)
KUNAL DATTA
UNIT V : Radiopharmaceuticals

2. Radiopharmaceuticals

3. Radioactivity
• The spontaneous emission of α particle or β particle and γ
waves from an unstable nuclei is called Radioactivity.
• Radioactive substance have a property of emitting rays or
particles which affect the photographic plate.
• The elements are known as radioactive because they are
unstable and undergo decomposition along with emission of
rays.
• The radiations or rays which are emitted are following:
Alpha particle , Beta particle and Gamma Rays

4. Alpha Particle (α)
• Alpha particle is alternatively known as Alpha radiation or
Alpha ray.
• It is a positively charged particle emitted from the decay of
various radioactive material.
• Alpha ray nucleus is very similar to the Helium nucleus
4
2He. Represented by Greek alphabet α.

5. Beta Particle (β)
• Beta particles (also referred to as beta radiation or beta
rays, denoted by the symbol β) can be defined as positrons
or electrons of extremely high speeds that hold extremely
high levels of energy.
• These are of two types: Electrically positive particles are
called as ‘positrons’ and Electrically negative particles
called as ‘negatrons’.
Negative beta decay
Positive beta decay

6. γ -rays or γ Particle
• These have more penetrating power than alpha and beta rays. They have
no mass or charge.
• They travel at the speed of light (3 × 108 m/s).
• The penetrating power of g-radiation has been found to depend on
atomic weight of absorbent and wavelength of radiations.
• Gamma radiation does not consist of charged particles, it is a form of
very short wavelength electromagnetic energy .

7. Properties of α, β and γ Radiations

8. Half-Life
• Half-life period (T or t1/2) of a radioactive substance is the time required to
disintegrate one-half of the original amount of the substance.
• We can describe exponential decay by the following given decay equation:
The half-life of the substance = t1/2 = ln2/ λ = 0.693/ λ
λ = The disintegration constant or decay constant
• The t1/2 of a nuclide will decide its utility in medicine. Too short t1/2 will be
inconvenient to setting up a satisfactory experiment. Too long t1/2 is an
absolute property of a nuclide and is unaffected by chemical or biological
conditions.

9. Units of Radioactivity
• Curie: Radioactivity is expressed in curies per gm of material (c/g) or as millicuries
per gm of material (mc/g).
• International System (SI): In SI system the unit of radioactivity is one nuclear
transmutation per second and is expressed in Becquerel (Bq), named after the
Scientist Henri Bequerel.
• Roentgen (R) : It is the unit of exposure to radioactive radiation.
1R = 2.58 × 10−4 C/kg, where C is coulomb.
• RAD : It is the unit of absorbed dose. 1 rad = 10−2 J/kg. For tissue, the roentgen and
RAD have been regarded to be numerically equivalent.
Radio-pharmaceutical dosage forms may be described in terms of RAD units.

10. Radioactive isotopes
• Isotopes are atoms with the same atomic number but different
mass numbers .
• Radioisotopes/radioactive isotopes of an element can be defined
as atoms that contain an unstable nucleus and scatter excess
energy by spontaneously emitting radiation in the form of
alpha, beta and gamma rays.

11. Example of Radioactive Isotopes

12. Pharmaceutical Application Of Radioactive Substances
Treatment of Cancers and Tumours
• Americium 241 used as antineoplastic.
• Californium 252 used as antineoplastic.
• Cobalt 60 used as antineoplastic.
• Gold 94 used as antineoplasatic.
• Holmium 66 (26 h) being developed for diagnosis and treatment of liver
cancer
• Iodine-125 (60 d) used in cancer prostate and brain cancer.
Treatment of Thyroid Disease with Iodine 131
• Iodine-131 is therapeutically used for to treat thyroid cancer,
hyperthyroidism diseases.
Treatment of Arthritis
• Erbium-169: Use for relieving arthritis pain in synovial joints

13. Pharmaceutical Application Of Radioactive Substances
Palliative Treatment of Bone Metastasis
 Various radioisotopes and pharmaceuticals are used to deliver palliative
treatment of bone metastases, including samarium-153 (Sm-153),
strontium-89 (Sr-89) chloride, and phosphorus-32 (P-32) sodium
phosphate.
 The two most common side effects occurring from radiopharmaceutical
therapy for metastatic bone disease are initial increased bone pain (flare)
and a decrease in WBC and platelet counts.

14. Storage of Radioactive Substances
Radiopharmaceuticals should be kept in well-closed
containers
 Radiopharmaceutical preparations that are
intended for parenteral use should be kept in a glass
vial, ampoule or syringe.

15. Precautions For Handling Radioactive Substances
• The radioactive substances used should comply with the following
characteristics:
 Radiotoxicity must be as low as possible.
 Short-living isotopes are preferred to long-living ones
 The amounts used must be kept to a minimum.
• Never work alone in a radioactive lab
• When handling radioactive materials, always wear the appropriate
protective clothing
• Use appropriate radiation shields. Return the stock solution to storage
immediately after removing the amount needed.

16. Precautions For Handling Radioactive Substances
• To avoid internal contamination, strict hygiene is essential when handling
radioactive materials .
 Eating, smoking, drinking, and applying cosmetics are prohibited in
radioactive labs.
 Never pipette by mouth. Use pipetting devices instead.
 Wash your hands thoroughly when you leave the lab.
• Regularly check the radiation level of your working area and all objects
used, or at least at the end of each working day.
• Replace contaminated absorption paper. Decontaminate contaminated
objects.
• Dispose of all radioactive waste in the appropriate containers.