Imipramine Pamoate Polymorph Control via Parameter Changes
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Solution Overview
Problem
The pharmaceutical industry lacks effective methods for characterizing and controlling the polymorphic forms of imipramine pamoate, which affects its stability, bioavailability, and pharmacokinetic behavior, limiting the development of generic drug products and therapeutic applications.
Innovation Solution
Development of novel polymorphic forms of imipramine pamoate, including amorphous and blended forms, characterized by differential scanning calorimetry, infrared spectroscopy, and powder X-ray diffraction, along with a synthetic process to produce and purify these forms, enabling controlled phase transitions and heat of fusion, and a pharmaceutical composition suitable for various therapeutic uses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional methods are used to prepare pamoate salts, then the conversion of liquid API to solid and improvement of organoleptic properties is achieved, but the ability to control polymorphic forms and ensure consistent physical properties is lost
Solution Approach 1:
The patent applies parameter changes by systematically varying temperature, pH, and solvent composition during the salt formation process to control which polymorphic form of imipramine pamoate is produced. By adjusting these parameters, the invention selectively obtains desired polymorphic forms (Form I, Form II, Form III, Form IV, Form V, Form VI, or Form VII) with specific physical properties, resolving the contradiction between manufacturing simplicity and polymorphic control.
Solution Approach 2:
The patent employs preliminary action by pre-establishing specific process conditions and using seed crystals or pre-formed polymorphic forms to guide the formation of desired polymorphic structures during salt preparation. This ensures consistent polymorphic form production while maintaining relatively simple manufacturing procedures.
2Adaptability or versatility
If multiple polymorphic forms are produced, then the variety of physical properties and potential therapeutic applications is improved, but the difficulty of characterizing and controlling these forms increases
Solution Approach 1:
The patent replaces complex mechanical separation methods with analytical techniques such as differential scanning calorimetry (DSC), powder X-ray diffraction (PXRD), and infrared spectroscopy to characterize polymorphic forms. These analytical methods provide clear differentiation and identification of various polymorphic forms (I-VII) without requiring complex mechanical separation processes, thus reducing characterization difficulty while maintaining versatility.
Solution Approach 2:
The patent utilizes distinct physical characteristics including melting point variations and thermal behavior patterns (analogous to color changes) to differentiate and identify various polymorphic forms. Each form exhibits unique thermal transitions and physical properties that serve as diagnostic markers, simplifying the detection and measurement of multiple forms.
3Reliability
If amorphous and blended forms are developed, then the bioavailability and dissolution characteristics are improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent applies parameter changes by controlling cooling rates, pH levels, and solvent evaporation conditions to generate amorphous forms and specific blended forms (e.g., Form V containing Forms I and III). These controlled parameter variations enable production of forms with enhanced bioavailability and dissolution characteristics while maintaining manageable manufacturing precision through established process controls.
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 novel polymorphic forms of imipramine pamoate provide improved stability, bioavailability, and therapeutic efficacy, enabling effective treatment of depression, fibromyalgia, childhood nocturnal enuresis, adult urinary incontinence, trichotillomania, post-traumatic stress disorder, and analgesic-like relief for neuropathic pain.
Implementation Method 1
characterized by differential scanning calorimetry, infrared spectroscopy, and powder X-ray diffraction
Implementation Method 2
enabling controlled phase transitions and heat of fusion
Implementation Method 3
characterized by differential scanning calorimetry, infrared spectroscopy, and powder X-ray diffraction
Implementation Method 4
characterized by differential scanning calorimetry, infrared spectroscopy, and powder X-ray diffraction
Implementation Method 5
characterized by differential scanning calorimetry, infrared spectroscopy, and powder X-ray diffraction
Implementation Method 6
a synthetic process to produce and purify these forms, enabling controlled phase transitions
Implementation Method 7
enabling controlled phase transitions and heat of fusion
Implementation Method 8
enabling controlled phase transitions and heat of fusion
Data Source
AI summary
An amorphous form of imipramine pamoate, morphologically pure forms, and mixtures of amorphous and morphologically pure imipramine pamoate characterized by differential scanning calorimetry, fourier transform infrared, and powder x-ray diffraction, and pharmaceutical compositions formed therefrom.