Gadolinium DOTA Complex Production via Stoichiometric Base Adjustment
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Solution Overview
Problem
The existing methods for producing liquid pharmaceutical preparations containing macrocyclic chelate complexes, such as gadoteric acid-meglumine salt, are complex, costly, and inefficient, often resulting in incomplete complexing and the presence of uncomplexed gadolinium, making them unsuitable for industrial-scale production.
Innovation Solution
A method involving the production of an aqueous solution with free DOTA, gadolinium, and a base like L-lysine or meglumine, where the components are reacted together at elevated temperatures, with subsequent adjustments to ensure complete complexing and the absence of free gadolinium, allowing for precise control of DOTA concentration within a specific range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the existing method from EP 2 242 515 B1 is used for producing liquid pharmaceutical preparation, then the complexing reaction can be performed, but the process becomes expensive and difficult to apply on industrial scale due to numerous adjustment steps
Solution Approach 1:
The patent changes the pH parameter by adding a base (meglumine or L-lysine) to shift the reaction conditions, enabling complete complexing of gadolinium without requiring multiple adjustment steps. This single parameter change resolves the contradiction by simplifying the process while ensuring complete reaction.
2Ease of manufacture
If free macrocyclic chelate and free lanthanide are mixed in amounts where entire lanthanide is not complexed, then adjustment steps are necessary, but this makes the method expensive and not readily applicable on industrial scale
Solution Approach 1:
The patent performs preliminary action by pre-calculating and adding the exact stoichiometric amount of base required for complete complexing before the reaction begins. This eliminates the need for subsequent adjustment steps during manufacturing, making the process both easier to implement industrially and faster.
3Reliability
If strict adherence to method steps of Example 2 in EP 2 242 515 B1 is followed, then the procedure can be reproduced, but complexing is only around 88% complete and free gadolinium remains uncomplexed
Solution Approach 1:
The patent implements feedback by measuring the concentration of free gadolinium and free DOTA, then using this information to precisely calculate and add the exact amount of base needed to achieve complete complexing. This closed-loop approach ensures 100% complexing completeness and eliminates free gadolinium from the final product.
4Manufacturing precision
If excess chelate adjustment is attempted as indicated in Item 1d of Claim 1 of EP 2 242 515 B1, then target concentration can be achieved, but the presence of both complexed and free form components prevents proper adjustment
Solution Approach 1:
The patent uses the base (meglumine or L-lysine) as an intermediary substance that facilitates complete complexing by neutralizing excess protons and shifting the equilibrium. This intermediary enables precise control of free chelate concentrations without the complications of adjusting mixtures containing both complexed and free forms.
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
This method simplifies the production process, ensures complete complexing of gadolinium, and eliminates the risk of free gadolinium in the final product, resulting in a stable and effective contrast medium.
Implementation Method 1
complex that consists of the macrocyclic chelate DOTA with gadolinium
Implementation Method 2
Carrying out the complexing at elevated temperature
Data Source
AI summary
A method for producing a liquid pharmaceutical preparation which contains a complex consisting of DOTA and gadolinium and a base such as L-lysine or meglumine, includes the following steps: a) An aqueous solution containing free DOTA, free gadolinium and a base such as L-lysine or meglumine is produced. b) The yield of free DOTA and free gadolinium is determined in the solution obtained according to step a). c) Free gadolinium and/or free DOTA is added in order to adjust a stoichiometric excess of free DOTA in the solution. d) The complexation is executed at an increased temperature. e) Additional base such as L-lysine or meglumine is added in order to adjust the pH value. f) The final volume of the preparation is adjusted.