Stable Crystal of 4-Oxoquinoline Compound for Pharmaceutical Stability
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Solution Overview
Problem
There is a need for a stable crystal form of 6-(3-5 chloro-2-fluorobenzyl)-1-[(S)-1-hydroxymethyl-2-methylpropyl]-7-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylic acid (compound A) to ensure chemical and physical stability for pharmaceutical applications, particularly as an anti-HIV agent.
Innovation Solution
The development of specific crystal forms, such as crystal form II and crystal form III of compound A, which exhibit characteristic X-ray powder diffraction patterns and thermal stability, including an extrapolated onset temperature of 162.1±5.0° C, ensuring stability and purity of at least 70%.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a compound is used as a pharmaceutical product, then chemical and physical stability is required to maintain quality and facilitate preservation, but without specific crystal form selection, stability cannot be ensured
Solution Approach 1:
The patent applies parameter changes by identifying and selecting specific crystal forms (Form I, Form II, Form III) with distinct physical parameters (X-ray diffraction patterns, melting points, densities) to achieve optimal stability. By changing the physical state parameters through controlled crystallization, the compound achieves enhanced chemical and physical stability for pharmaceutical applications.
Solution Approach 2:
The patent utilizes phase transitions by studying the crystallization process and identifying stable crystal forms from amorphous or less stable forms. The invention documents phase transition data including melting points and X-ray diffraction patterns to characterize stable crystal forms that maintain compound integrity during storage and formulation.
2Reliability
If crystal polymorphism is present, then the most stable crystal should be selected for pharmaceutical use, but without concrete crystal form descriptions, selection cannot be made
Solution Approach 1:
The patent creates a reference database by documenting and copying the characteristic physical properties of stable crystal forms (X-ray powder diffraction patterns, melting points, densities, solubility characteristics). This information copy serves as a reference for selecting and verifying stable crystal forms in future pharmaceutical development, preventing loss of critical crystal form data.
Solution Approach 2:
The patent replaces mechanical/physical trial-and-error crystal selection with systematic characterization methods using X-ray diffraction, thermal analysis, and spectroscopy. These analytical techniques provide objective criteria for identifying stable crystal forms without relying on empirical guessing or incomplete data.
3Reliability
If stable crystal forms are developed with specific X-ray diffraction patterns and thermal properties, then physical and chemical stability is enhanced, but characterization and verification processes become more complex
Solution Approach 1:
The patent implements feedback mechanisms by establishing characteristic fingerprint data (X-ray diffraction patterns, melting points, densities) for stable crystal forms and using this feedback to verify crystal form identity and purity. The verification process compares measured properties against established reference values to confirm crystal form stability and consistency.
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
These stable crystal forms of compound A enhance physical and chemical stability, facilitating long-term quality maintenance and simplifying the production of pharmaceutical compositions, thereby reducing production costs.
Implementation Method 1
a crystal (crystal form II) of 6-(3-chloro-2-fluorobenzyl)-1-[(S)-1-hydroxymethyl-2-methylpropyl]-7-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylic acid, which has an X-ray powder diffraction pattern having characteristic diffraction peaks at diffraction angles 2θ(°) of 6.56, 13.20, 19.86, 20.84, 21.22, 25.22° as measured by X-ray powder diffractometer
Implementation Method 2
a crystal (crystal form III) of 6-(3-chloro-2-fluorobenzyl)-1-[(S)-1-hydroxymethyl-2-methylpropyl]-7-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylic acid, having an extrapolated onset temperature of 162.1±5.0° C.
Data Source
AI summary
The present invention provides a crystal of 6-(3-chloro-2-fluorobenzyl)-1-[(S)-1-hydroxymethyl-2-methylpropyl]-7-methoxy-4-oxo-1,4-dihydroquinoline-3-carboxylic acid, which shows a particular powder X-ray diffraction pattern of a characteristic diffraction peaks at diffraction angles 2θ(°) as measured by powder X-ray diffractometry. The crystal of the present invention is superior in physical and chemical stability.