Bazedoxifene Acetate Form D Crystallization Control
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Solution Overview
Problem
The challenge lies in predicting and stabilizing the crystalline polymorphic forms of bazedoxifene acetate, as different forms exhibit varying physical properties such as solubility and stability, making it difficult to determine the preferred form for drug preparation and treatment, and there is a need for methods to prevent conversion between polymorphs.
Innovation Solution
A novel polymorphic form, Form D of bazedoxifene acetate, is developed with specific X-ray powder diffraction patterns, Raman spectra, and differential scanning calorimetry characteristics, which can be prepared through a method involving hexamethylenimino benzyloxyindole reaction in ethanol with a catalyst and antioxidant, followed by acetic acid treatment, and formulated with a pharmaceutically acceptable carrier for effective treatment of estrogen-related disorders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional crystallization methods are used to prepare bazedoxifene acetate, then the drug can be obtained, but it is difficult to predict and control which polymorphic form will crystallize, leading to variability in physical properties such as solubility and stability
Solution Approach 1:
The patent applies parameter changes by systematically varying crystallization conditions including solvent composition (ethanol/water ratios), temperature profiles (cooling rates from 0.1 to 10°C per minute), pH levels (using acetic acid adjustment), and concentration parameters to selectively obtain different polymorphic forms. This allows precise control over which polymorph crystallizes based on desired physical properties.
Solution Approach 2:
The patent employs preliminary action through seed crystals - adding pre-formed crystals of the desired polymorphic form to the supersaturated solution before final crystallization occurs. This seeding technique pre-determines the crystal lattice structure that will form, ensuring consistent polymorphic form production and preventing conversion to other forms during storage.
2Reliability
If a polymorphic form with higher solubility is selected, then bioavailability may be improved, but the form may be less stable and more prone to conversion to other polymorphs during storage
Solution Approach 1:
The patent utilizes parameter changes to identify and characterize multiple polymorphic forms with different solubility-stability profiles. By controlling crystallization parameters such as solvent composition, temperature, and pH, the patent enables selection of specific polymorphic forms that optimize the balance between solubility for bioavailability and stability for storage, with Form D representing a stable configuration.
Solution Approach 2:
The patent employs copying through the use of seed crystals - reproducing the desired polymorphic form structure by introducing pre-formed crystals of that specific form into the crystallization process. This ensures that the stable polymorphic form is replicated consistently, preventing unwanted conversions and maintaining compositional integrity throughout storage and formulation.
3Manufacturing precision
If extensive screening of crystallization conditions is performed to identify stable polymorphic forms, then the desired form can be obtained, but the development time and resource requirements increase significantly
Solution Approach 1:
The patent systematically explores parameter changes across key crystallization variables - solvent composition (ethanol/water ratios from 10:0 to 0:10), temperature ranges (4°C to 40°C), pH levels (adjusted with acetic acid), and cooling rates (0.1 to 10°C per minute). This structured parameter variation efficiently identifies stable polymorphic forms like Form D without requiring exhaustive screening of all possible conditions.
Solution Approach 2:
The patent demonstrates universality by developing a multi-functional crystallization protocol that can produce different polymorphic forms by simply adjusting parameters rather than requiring entirely different processes. The same basic crystallization setup can yield Forms A, B, or D depending on solvent composition, temperature, and seeding conditions, reducing development time and resource requirements.
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 polymorphic Form D of bazedoxifene acetate provides enhanced stability and solubility, allowing for effective treatment of conditions like osteoporosis, endometrial disorders, and menopausal symptoms, with improved pharmacokinetics and reduced conversion to other forms, thus addressing the challenges of polymorphic stability and treatment efficacy.
Implementation Method 1
contacting hexamethylenimino benzyloxyindole with hydrogen in a solvent comprising ethanol, and in the presence of a catalyst at elevated temperature to provide a first reaction mixture comprising bazedoxifene free base
Implementation Method 2
treating said first reaction mixture with an antioxidant to provide a second reaction mixture
Implementation Method 3
treating said solution with acetic acid to crystallize polymorphic Form D of bazedoxifene acetate
Data Source
AI summary
The present disclosure relates to polymorphic Form D of bazedoxifene acetate, pharmaceutical compositions and methods of treatment using the same, and methods of preparing the same.