Leucovorin Calcium Injection Formulation for Crystallization Stability
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Solution Overview
Problem
Current leucovorin formulations face challenges with low aqueous solubility and crystallization during storage, leading to physical instability and safety risks, particularly under refrigerated conditions, necessitating a stable, ready-to-use injectable solution.
Innovation Solution
A formulation comprising leucovorin calcium, cyclodextrin derivatives, and excipients is developed, with a specific sequence of addition and pH control to prevent crystallization, ensuring chemical and physical stability during storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If leucovorin is formulated as a high-strength aqueous injectable solution, then the therapeutic benefit and convenience are improved, but the physical stability deteriorates due to crystallization during storage
Solution Approach 1:
Cyclodextrin derivatives are used as intermediary substances that form inclusion complexes with leucovorin, enhancing its aqueous solubility and preventing crystallization. The cyclodextrin cavity encapsulates the leucovorin molecule, creating a stable complex that remains dissolved in aqueous solution during refrigerated storage, thus resolving the contradiction between high concentration and physical stability
Solution Approach 2:
The formulation employs pH adjustment to optimize the solubility and stability characteristics of leucovorin. By controlling the pH within a specific range, the ionization state of leucovorin is modified, enhancing its compatibility with cyclodextrin derivatives and preventing precipitation, thereby maintaining physical stability at high concentrations
2Stability of the object's composition
If leucovorin is formulated as a low-strength solution (e.g., 6.35 mg/mL), then the physical stability is improved, but the therapeutic benefit is limited
Solution Approach 1:
The formulation creates a composite system combining leucovorin with cyclodextrin derivatives and other excipients. This composite approach allows the leucovorin to be delivered at higher effective concentrations while the cyclodextrin matrix prevents crystallization, thus achieving both high therapeutic benefit and physical stability simultaneously
3Stability of the object's composition
If leucovorin is provided as lyophilized powder requiring reconstitution, then the storage stability is improved, but the ease of operation deteriorates due to time-consuming preparation and contamination risk
Solution Approach 1:
The formulation performs the solubilization and stabilization actions in advance during manufacturing. Cyclodextrin derivatives are pre-complexed with leucovorin to create a stable aqueous solution that requires no further preparation. This preliminary action eliminates the need for reconstitution at the point of use, providing both storage stability and ease of administration
4Quantity of substance
If conventional stabilizing additives are used, then the solubility is improved to some extent, but the long-term physical stability under refrigerated storage deteriorates due to crystallization
Solution Approach 1:
The formulation uses cyclodextrin derivatives as sacrificial stabilizing agents that preferentially interact with leucovorin to prevent crystallization. These cyclodextrins act as temporary protective structures during storage, maintaining solubility and preventing precipitation over the product shelf life, thus achieving long-term physical 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 formulation maintains clarity and stability for up to 24 months under refrigerated conditions, eliminating the need for reconstitution and reducing product recalls, enhancing patient safety and clinical efficiency.
Implementation Method 1
EP0427078 reports complexes of leucovorin salts with cyclodextrins which are stable at acidic pH
Implementation Method 2
a buffering agent, a pH adjusting agent and a pharmaceutically acceptable vehicle
Implementation Method 3
Formulating such stable aqueous injections of leucovorin salt poses significant challenges due to the compound's low aqueous solubility and tendency to crystallize during storage
Data Source
AI summary
Described herein are clear, stable aqueous formulations comprising—in relevant part—leucovorin calcium; substituted cyclodextrins, specifically betadex suclfobutyl ether cyclodextrin (SBE-β-CD) or hydroxypropyl beta cyclodextrin (HP-β-CD), designed for parenteral administration. The formulations are designed to effectively prevent drug crystallization and particulate matter formation, addressing major stability challenges associated with existing products. These advancements not only improve the safety and efficacy of leucovorin calcium for intravenous administration but also facilitate compliance with regulatory standards, providing a reliable therapeutic option for patients. Methods of making and using these formulations are also described herein.