Dihydrate Crystal Stability for Hygroscopic API
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Solution Overview
Problem
The (S)-(−)-1-(4-fluoroisoquinolin-5-yl)sulfonyl-2-methyl-1,4-homopiperazine hydrochloride anhydrous crystals exhibit hygroscopic instability, leading to changes in weight, crystal form, and volume, which complicates drug storage and stability, particularly under humid conditions.
Innovation Solution
The development of (S)-(−)-1-(4-fluoroisoquinolin-5-yl)sulfonyl-2-methyl-1,4-homopiperazine hydrochloride dihydrate, which is produced by dissolving the anhydrous form in water and adding a hydrophilic organic solvent, resulting in a non-hygroscopic compound with enhanced thermal stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If anhydrous crystals are used, then water solubility is achieved, but hygroscopic stability deteriorates
Solution Approach 1:
The invention changes the hydration state parameter of the compound from anhydrous (0 water molecules) to dihydrate (2 water molecules per formula unit). This parameter change fundamentally alters the compound's interaction with moisture: the dihydrate form has a stable crystal structure that prevents further water absorption, eliminating the hygroscopic instability problem while preserving water solubility for pharmaceutical application.
2Ease of operation
If anhydrous crystals are stored under humid conditions, then storage flexibility improves, but crystal structure stability deteriorates
Solution Approach 1:
The invention performs preliminary hydration by converting the anhydrous form to the dihydrate form before storage. This preliminary action of incorporating water molecules into the crystal lattice during manufacturing eliminates the need for subsequent rigorous moisture control during storage. The dihydrate crystals are pre-adapted to humid conditions, maintaining structural stability without requiring special storage precautions.
3Quantity of substance
If moisture absorption occurs, then water content increases, but weight stability deteriorates
Solution Approach 1:
Instead of preventing water absorption (the conventional approach), the invention inverts the strategy by deliberately incorporating water molecules into the crystal structure during manufacturing. The dihydrate form is produced with a fixed, stoichiometric water content, which stabilizes the weight rather than causing weight variation. This inversion transforms water from a harmful variable into a beneficial constant.
4Stability of the object's composition
If rigorous moisture control is implemented, then hygroscopic stability improves, but storage complexity increases
Solution Approach 1:
The dihydrate form exhibits self-service properties regarding moisture stability. The crystal structure inherently resists further water absorption under normal storage conditions, making the compound self-stabilizing against hygroscopic degradation. This self-service characteristic eliminates the need for complex external moisture control systems, desiccants, or specialized storage equipment, thereby reducing storage complexity while maintaining hygroscopic 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 dihydrate exhibits excellent hygroscopic stability and thermal stability, preventing moisture-induced changes and ensuring stable storage and bioavailability, making it a suitable base material for medicines, particularly for treating cerebrovascular disorders.
Implementation Method 1
exhibits excellent hygroscopic stability; assumes the form of virtually non-hygroscopic crystals, whereby change in weight and in crystal form induced by absorption of moisture as well as change in volume concomitant therewith are prevented
Data Source
AI summary
The present invention is directed to (S)-(−)-1-(4-fluoroisoquinolin-5-yl)sulfonyl-2-methyl-1,4-homopiperazine hydrochloride dihydrate, to a method producing the dihydrate, and to a drug composition containing the dihydrate. The compound of the present invention has less hygroscopicity as compared with (S)-(−)-1-(4-fluoroisoquinolin-5-yl)sulfonyl-2-methyl-1,4-homopiperazine hydrochloride anhydrous crystals and thus, exhibits excellent chemical stability.