Radionuclide Complex Formulation for Radiolysis-Stable High Concentration
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Solution Overview
Problem
Existing radiopharmaceutical drug products face challenges with radiolytic degradation during manufacturing and storage, leading to instability and the need for on-site preparation, which complicates administration and patient comfort, especially when concentrated solutions are required.
Innovation Solution
A process involving the sequential use of gentisic acid and ascorbic acid as stabilizers to form a stable radionuclide complex with DOTA-TATE or DOTA-TOC, allowing for high-concentration, ready-to-use solutions that maintain chemical and radiochemical stability at ambient or elevated temperatures, eliminating the need for on-site preparation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the radionuclide complex solution is stored at low temperatures, then stability is improved, but storage conditions become more complex and costly
Solution Approach 1:
The patent changes the chemical composition parameters by introducing specific stabilizers (ascorbic acid at 0.1-10 mg/mL and gentisic acid at 0.01-1 mg/mL) to alter the stability characteristics of the radionuclide complex solution, enabling it to maintain stability at higher temperatures without requiring specialized cold storage infrastructure
Solution Approach 2:
The patent introduces stabilizer molecules as intermediary substances that mediate between the radionuclide complex and the environment, protecting the complex from radiolytic degradation and allowing storage at ambient temperatures by absorbing or neutralizing harmful radiation effects
2Reliability
If the drug product is produced in high dilution, then radiolysis is reduced, but large volumes of infusion solutions need to be administered
Solution Approach 1:
Stabilizer molecules act as intermediaries that protect the radionuclide complex from radiolytic degradation, enabling high concentration formulations without the harmful effects of radiolysis by absorbing radiation energy and preventing bond cleavage in the drug molecules
Solution Approach 2:
The patent changes the concentration parameter by formulating radionuclide complex solutions at high concentrations (achieved through optimized complexation conditions and stabilizer addition) while maintaining stability through the protective effect of stabilizers, thereby reducing the total infusion volume required
3Reliability
If ethanol is used as a stabilizer, then radiolysis is reduced, but physiological tolerability deteriorates
Solution Approach 1:
The patent replaces ethanol stabilizers with ascorbic acid and gentisic acid as intermediary substances that perform the same radioprotective function but without the harmful physiological effects of ethanol, thereby maintaining radiolysis resistance while improving patient tolerability
Solution Approach 2:
The patent uses biocompatible, metabolizable substances (ascorbic acid and gentisic acid) as stabilizers that can be safely administered to patients and metabolized by the body, replacing ethanol which has unacceptable physiological side effects at the required stabilizing concentrations
4Reliability
If freeze-dried kits are used, then stability is improved, but preparation complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-formulating the radionuclide complex with stabilizers in a ready-to-use liquid state, eliminating the need for freeze-drying and subsequent reconstitution steps that are required with traditional kit formulations
Solution Approach 2:
The patent changes the physical state parameter from frozen/desiccated (freeze-dried kits) to liquid by developing stable liquid formulations through stabilizer addition, thereby eliminating the complexity of freeze-drying and reconstitution while maintaining stability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The process ensures high chemical and radiochemical stability, enabling the production of a ready-to-use, high-concentration radiopharmaceutical solutions that can be stored for at least 3 days and administered to patients without ethanol and can be shipped to remote clinical centers for immediate use, maintaining efficacy and patient comfort.
Implementation Method 1
the decay of the radionuclide occurs constantly, e.g. also during the manufacturing and during storage of the drug product, and the released high energy emissions induce the cleavage of the chemical bonds of the molecules which form part of the drug product. This is often referred to as radiolysis or radiolytic degradation
Implementation Method 2
forming a complex of (i) 177Lu or (i') 68Ga with (ii) DOTA-TATE or DOTA-TOC in aqueous solution at a volumetric radioactivity of from 3.7 to 20 GBq/mL
Data Source
AI summary
The present invention relates to radionuclide complex solutions of high concentration and of high chemical stability, that allows their use as drug product for diagnostic and/or therapeutic purposes. The stability of the drug product is achieved by at least one stabilizer against radiolytic degradation. The use of two stabilizers introduced during the manufacturing process at different stages was found to be of particular advantage.