Amorphous Drug Dispersions with Concentration-Enhancing Polymers
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Solution Overview
Problem
Low-solubility drugs often exhibit poor bioavailability and irregular absorption due to their crystalline form, which is not physically or chemically stable, and existing methods to form amorphous dispersions with polymers face challenges such as instability and incompatibility with processing methods.
Innovation Solution
A solid dispersion comprising a low-solubility drug in an amorphous form combined with a concentration-enhancing polymer, where at least 10 wt % of the matrix is non-polymeric, providing improved stability and bioavailability by maintaining a higher drug concentration in the gastrointestinal tract.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If amorphous dispersions of drugs with polymers are formed to increase bioavailability, then the drug concentration in solution is temporarily enhanced, but the improved concentration is short-lived and quickly returns to lower equilibrium concentration
Solution Approach 1:
The patent introduces a concentration-enhancing polymer as an intermediary substance that interacts with the amorphous drug dispersion to maintain elevated drug concentration in the gastrointestinal tract. This polymer acts as a mediator that prevents rapid precipitation and extends the duration of enhanced bioavailability beyond what the amorphous dispersion alone could achieve.
Solution Approach 2:
The invention creates a composite system combining amorphous drug dispersion with a concentration-enhancing polymer. This composite formulation synergistically combines the rapid dissolution capability of amorphous forms with the concentration-maintaining properties of the polymer, resulting in prolonged elevated drug concentration and improved bioavailability.
2Speed
If amorphous form of drug is used to improve dissolution rate, then the drug dissolves faster than crystalline form, but the amorphous drug is not stable physically and tends to crystallize over time
Solution Approach 1:
The concentration-enhancing polymer serves as a stabilizing intermediary that prevents crystallization of the amorphous drug. By interacting with the drug molecules in the dispersion, the polymer maintains the amorphous state and physical stability while preserving the rapid dissolution rate, thus resolving the contradiction between speed and stability.
Solution Approach 2:
The invention changes the physical-chemical parameters of the drug dispersion by incorporating the concentration-enhancing polymer, which alters the glass transition temperature, viscosity, and molecular environment. These parameter changes stabilize the amorphous form thermodynamically while maintaining its kinetic advantage in dissolution rate.
3Quantity of substance
If dispersion of drug and polymer is formed to enhance bioavailability, then the drug concentration is improved, but the dispersion may be physically unstable causing the amorphous drug to separate and/or crystallize
Solution Approach 1:
The patent optimizes formulation parameters including the ratio of polymer to drug, molecular weight of the polymer, and processing conditions to achieve a physically stable dispersion. By carefully controlling these parameters, the formulation maintains homogeneity and prevents phase separation while delivering enhanced drug concentration.
Solution Approach 2:
The invention develops a stable composite dispersion where the concentration-enhancing polymer and amorphous drug are molecularly mixed. This composite structure, achieved through specific processing methods, creates a thermodynamically stable system that maintains uniform distribution and prevents crystallization or separation during storage and in vivo.
4Ease of manufacture
If solvent processing is used to form dispersion of drug and polymer, then the dispersion can be formed, but the drug and polymer may not both be soluble to sufficient extent in appropriate processing solvent
Solution Approach 1:
The patent employs parameter changes in the processing method, including using non-aqueous solvents, adjusting temperature, or employing sonication and high-shear mixing. These parameter modifications enable the formation of stable dispersions even when the drug and polymer have limited mutual solubility, overcoming the solubility constraint while maintaining ease of manufacture.
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 composition achieves enhanced bioavailability by maintaining a higher drug concentration and prolonged absorption, reducing the need for higher drug dosages and minimizing absorption variability across different gastrointestinal states.
Implementation Method 1
the amorphous form of a low-solubility drug that is capable of existing in either the crystalline or amorphous form may temporarily provide a greater aqueous concentration of drug relative to the equilibrium concentration obtained by dissolution of drug in a use environment
Implementation Method 2
the amorphous form may temporarily provide a greater-than equilibrium concentration of drug
Data Source
AI summary
A pharmaceutical composition comprises a dispersion comprising a low-solubility drug and a matrix combined with a concentration-enhancing polymer. At least a major portion of the drug is amorphous in the dispersion. The compositions improve the stability of the drug in the dispersion, and/or the concentration of drug in a use environment.