Stable, concentrated radionuclide complex solutions
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Solution Overview
Problem
Existing radiopharmaceutical drug products face issues 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 create a highly concentrated, stable radionuclide complex solution, allowing for commercial-scale production and ready-to-use administration without ethanol, ensuring chemical and radiochemical stability even at elevated temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the radionuclide complex solution is stored at low temperatures, then stability against radiolysis is improved, but manufacturing complexity and cost increase due to cold chain requirements
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 radiolytic stability characteristics of the solution, enabling stability at ambient temperatures without requiring temperature control infrastructure
Solution Approach 2:
The patent introduces stabilizing agents as intermediary substances that mediate between the radionuclide complex and radiolytic degradation. These stabilizers act as protective intermediaries that scavenge free radicals and prevent radiolytic damage to the complex
2Stability of the object's composition
If the drug product is produced in high dilution to avoid radiolysis, then stability is improved, but patient comfort deteriorates due to large infusion volumes required
Solution Approach 1:
The patent changes the concentration parameter by enabling high concentration formulations (up to 20 GBq/mL) through the addition of stabilizers that prevent radiolytic degradation, thereby allowing concentrated solutions to be produced and administered without requiring large volumes
3Stability of the object's composition
If ethanol is added as a stabilizer against radiolysis, then stability is improved, but physiological tolerability deteriorates due to negative impact on patient comfort
Solution Approach 1:
The patent changes the chemical composition by substituting ethanol-based stabilization with water-soluble stabilizers (ascorbic acid and gentisic acid), thereby maintaining radiolytic stability while improving physiological tolerability and eliminating ethanol-related side effects
Solution Approach 2:
The patent employs short-lived stabilizing molecules (ascorbic acid and gentisic acid) that effectively scavenge radiolytic radicals during the brief storage and administration period, providing sufficient stabilization without requiring long-term stability or introducing persistent harmful substances
4Stability of the object's composition
If freeze-dried kits are used to enable on-site preparation, then stability during transport is improved, but device complexity increases due to required reconstitution and processing steps
Solution Approach 1:
The patent applies preliminary action by pre-formulating the complete radiopharmaceutical product with stabilizers in a ready-to-use liquid state, eliminating the need for on-site reconstitution and processing steps that would be required for freeze-dried kits
Solution Approach 2:
The patent extracts the stabilizing function from complex freeze-dried formulations and implements it through simple, stable liquid formulations containing ascorbic acid and gentisic acid, thereby simplifying the overall product structure and administration process
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 solution provides high stability, allowing for a shelf-life of at least 3 days and enabling centralized production, reducing patient discomfort by minimizing infusion volume and ensuring physiological tolerability.
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 with (ii) a cell receptor-binding moiety linked to a chelating agent in the presence of a first stabilizer selected from gentisic acid and a second stabilizer selected from ascorbic acid
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.