QC of radiopharmaceuticals Flashcards
What does Quality Assurance encompass in the context of radiopharmaceuticals?
The total process of in-house preparation and administration of radiopharmaceuticals to the patient
It includes quality control testing of dose calibrators and radiopharmaceuticals, proper dispensing, record keeping, and testing of radiopharmaceuticals.
What are the key components involved in achieving satisfactory quality assurance (QA)?
- Radiochemical analysis
- Environmental control and monitoring
- Adequate training of personnel
Name the categories of quality control tests for radiopharmaceuticals.
- Physicochemical Tests
- Biologic Tests
- Pharmaceutical Purity
What are the physicochemical tests performed on radiopharmaceuticals?
- Physical Appearance
- Chemical Purity
- Radionuclidic Purity
- Radiochemical Purity
What is assessed under the Physical Appearance test for radiopharmaceuticals?
- Color
- State (true solution or colloid)
- Particulate presence
- Particle size and number
What is the ideal pH for radiopharmaceuticals?
7.4 (although it can vary between 2 and 9)
This pH range is due to the high buffer capacity of blood.
Fill in the blank: Radiopharmaceuticals for I.V. use should be _______.
[isotonic]
What are some specific chemical impurities that can affect chemical purity?
- Excessive amounts of Tc-99g in Tc-99m preparation
- Aluminum (Al) breakthrough
- Excess or less SnCl2
- Traces of globulins in Albumins
What is the contamination limit for Aluminum (Al) in radiopharmaceutical preparations?
10 µg/mL
Define Radionuclidic Purity.
The fraction or percentage of the total radioactivity in the form of the desired radionuclide present in a radiopharmaceutical.
What are the disadvantages of Radionuclidic impurities?
- Increases undue radiation to the patient
- May obscure scintigraphic images
- Causes Radiolysis of radiopharmaceuticals
What is the acceptable limit for Radionuclide impurities in generator eluate?
< 5%
What is the purpose of the Dose Calibrator in the quality control of radiopharmaceuticals?
To assay (read) the activity of radiopharmaceuticals prior to administration to the patient.
List the tests performed to assure the proper functioning of the Dose Calibrator.
- Constancy test
- Linearity test
- Accuracy test
- Geometry test
What is Radiochemical Purity defined as?
The fraction or percentage of the total radioactivity in the preparation present in the defined chemical form of the constituent radionuclide.
What analytical methods are used to determine Radiochemical impurities?
- Instant Thin-Layer Chromatography (ITLC)
- Paper chromatography
- Column gel chromatography
- Filtration
- Precipitation
- Ion exchange
- Solvent extraction
- High-Performance Liquid Chromatography (HPLC)
- Distillation
True or False: Additives, buffers, acids, alkalis, and preservatives are considered chemical impurities.
False
What factors can cause Radiochemical impurities in a radiopharmaceutical?
- Solvent action
- Change in temperature or pH
- Light exposure
- Presence of oxidizing or reducing agents
- Radiolysis
What does the abbreviation F (%) represent in chromatographic analysis?
F represents the fraction of the total activity in the sample.
What is the purpose of checking the Tc-99m - MDP Analysis sheet?
To ensure the quality control of the radiopharmaceutical.
What equipment is needed for chromatographic analysis of 99mTcO4- and 99mTcO2?
- ITLC-SG paper x 2 (10cm strip)
- 1ml Acetone in McCartney bottle
- 1ml 0.9% saline McCartney bottle
What is the first step in the chromatographic method for 99mTc-MDP?
Place a drop of 99mTc-MDP on to the origin of a strip of ITLC-SG paper and place it into 1ml of Acetone.
What does Tube 1 (Rf = 0) contain in the chromatographic analysis?
99mTc-MDP and hydrolysed-reduced 99mTc.
How is the % free pertechnetate (A) calculated?
% free pertechnetate (A) = tube 2 x 100 / (tube 1 + tube 2)
What is the significance of a long or over air drying of the sample spot in chromatography?
It can lead to artifacts formation.
What is the acceptable pH range for NaTcO4-99m as per QC checks?
4.5 - 7.5
What does a radionuclidic purity greater than 99.9% indicate?
It indicates that more than 99.9% of the activity at the end of elution is due to Tc-99m.
What is the main challenge regarding quality control of radiopharmaceutical products?
Their short half-life.
What are the two basic methods for testing sterility?
- Culture method
- Radiometric testing
What is the principle of the culture method for testing sterility?
Inoculation of growth media with random or suspicious samples and checking for growth.
What is the incubation temperature for the culture method in sterility testing?
30-35°C for aerobic and anaerobic bacteria.
What is the principle of radiometric testing for sterility?
Incubate the sample in growth medium containing C-14 glucose and measure C-14 activity.
What is the sterilization method used for thermo-stable aqueous solutions?
Autoclaving at 121°C under 18 psi for 15-20 minutes.
What does the term ‘apyrogenicity’ refer to?
The absence of pyrogens or bacterial metabolic by-products.
Which test is officially known as the LAL test?
The bacterial endotoxin test (BET).
What are endotoxins known to cause?
Fever, septic shock, and other disease symptoms.
What are the advantages of the LAL test?
- Very sensitive
- Fast
- Small volume
- Includes positive and negative controls
- Lower cost
What is the main aim of toxicity tests for radiopharmaceuticals?
To determine toxicity limits and the type of toxicity.
What is the principle behind tests for acute toxicity?
Administering large doses to different groups of animals and observing them for toxic manifestations.
What must be ensured regarding the pharmaceutical purity of radiopharmaceuticals?
Freedom from toxicity, sterility, and apyrogenicity.
What is a critical aspect of the efficacy of radiopharmaceuticals?
Good quality diagnostic information resulting from their use.
What is the primary route of excretion for Tc-99m?
Primarily via GIT and kidneys.
What percentage of Tc-99m is recovered in urine over 24 hours?
0.3
What is the significance of biodistribution studies for radiopharmaceuticals?
To assure their in vivo retention and elimination.
What does the term ‘bio distribution’ refer to in the context of radiopharmaceuticals?
The distribution of the radiopharmaceutical in target and non-target organs.
What is the typical time frame for measuring the biodistribution of a radiopharmaceutical in studies?
After a fixed time post-injection, usually involving the sacrifice of the experimental animal.
What does 50/60 refer to in pharmacology?
Lethal dose at which 50% of animals die in 60 days
What aspects of purity are covered under Pharmaceutical Purity?
All relevant aspects of purity other than chemical, radiochemical & radionuclidic purity
What are essential requirements for all human parenteral products?
Sterility, apyrogenicity & freedom from toxicity
How is the efficacy of a radiopharmaceutical defined?
In terms of good quality diagnostic information resulting from its use
What are the characteristics of excellent quality scintigraphic images?
High target to non-target ratios & selective dose delivery
What must be ensured for the in-vivo stability of radiopharmaceutical preparations?
The product must be appropriately formulated
What is a common observation in patients indicating defects in radiopharmaceuticals?
Unexpected biodistribution
Which factors affect the integrity of radiopharmaceuticals?
- Radionuclidic purity
- Radiochemical purity
- Specific activity
- Particle size
- pH
- Sterility / apyrogenicity
What handling techniques can affect the integrity of radiopharmaceuticals?
- Injection technique into the patients
- Faulty syringe
- Dispensing/dilution technique
- Contamination of Radiopharmaceuticals with components of syringe
- Same syringe to dispense several products
- Storage condition
- Poor transport condition
What aspects are of prime importance in certain radiopharmaceutical products?
- Particle size of colloids & aggregated formulations
- Optimum number of particles in human dose
- Presence of stabilizers
What is significant for ensuring high in-vivo stability of labeled preparations?
Mode of incorporation of the labeling radionuclide & the site of labeling
What must be assured for labeled antibodies used in RadioImmunoScintigraphy (RIS) & RadioImmnoTherapy (RIT)?
The specific immunoreactivity of the labeled antibody