Hexadecyl Treprostinil Crystallization for Thermal Stability
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Solution Overview
Problem
The existing synthesis processes for Hexadecyl Treprostinil result in an off-white waxy solid form, which lacks thermal stability, purity, and homogeneity, making it difficult for commercial handling and storage, and there is no established method for obtaining a stable crystalline form.
Innovation Solution
A method involving the dissolution of Hexadecyl Treprostinil in specific solvents followed by temperature lowering and addition of secondary solvents to precipitate out crystalline forms, characterized by distinct XRPD and DSC patterns, resulting in stable crystalline forms (Form I and Form II) that can be stored at room temperature without transformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional synthesis processes are used to prepare Hexadecyl Treprostinil, then the product can be obtained as an off-white waxy solid, but the thermal stability, purity, and homogeneity are unsatisfactory
Solution Approach 1:
The patent applies phase transition by converting the amorphous waxy solid form of Hexadecyl Treprostinil into a crystalline form through controlled crystallization processes. The specific crystallization conditions (solvent selection, temperature control, addition of secondary solvents) induce a phase transition from disordered amorphous state to ordered crystalline state, thereby improving thermal stability, purity, and homogeneity while maintaining the active pharmaceutical ingredient's efficacy.
2Ease of operation
If Hexadecyl Treprostinil is provided as a waxy solid, then it can be directly obtained from synthesis, but it has high viscosity and is difficult for commercial handling to avoid sticking loss on container
Solution Approach 1:
The patent resolves the handling difficulty by inducing a phase transition from amorphous waxy solid to crystalline form. The crystalline structure reduces viscosity and eliminates the sticky properties characteristic of amorphous materials, enabling easy commercial handling, storage, and transport without sticking losses on container walls.
3Manufacturing precision
If no crystalline form is available, then the synthesis process remains simple, but the benefits of conventional crystallization methods cannot be evaluated and constant operating parameters cannot be provided
Solution Approach 1:
The patent employs parameter changes by systematically optimizing crystallization conditions including solvent selection (first solvent from a specified group), temperature control (lowering temperature to induce crystallization), and addition of secondary solvents (acetonitrile, water, or mixtures). These controlled parameter changes transform the simple synthesis process into a precise crystallization process that delivers consistent physicochemical properties and constant operating parameters for pharmaceutical manufacturing.
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 method produces stable crystalline forms of Hexadecyl Treprostinil that are easier to handle, maintain stability, and retain high assay values over time, offering improved storage and handling advantages compared to the waxy solid form.
Implementation Method 1
lowering the temperature and/or adding a second solvent selected from the group consisting of acetonitrile, water, and mixtures thereof to the homogenous solution; and stirring until a precipitate is formed
Implementation Method 2
stirring until a precipitate is formed
Implementation Method 3
lowering the temperature and/or adding a fourth solvent selected from the group consisting of pentane, hexane, heptane, octane, nonane, decane, cyclopentane, cyclohexane, cycloheptane, and mixtures thereof to the homogenous solution; and stirring until a precipitate is formed
Implementation Method 4
stirring until a precipitate is formed
Data Source
Figure 1~2
Figure 3~4
Figure 5~6
AI summary
There is provided stable crystalline Form I and Form II of Hexadecyl Treprostinil (C16TR) and processes for the preparation thereof. The stable crystalline Form I and Form II of Hexadecyl Treprostinil present advantages in storage, formulation, shipment and handling for commercially considerations.