Rifaximin Polymorphic Forms for Controlled Bioavailability
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Solution Overview
Problem
Current rifaximin formulations have limitations in terms of systemic absorption, which can lead to bacterial resistance and varying bioavailability, affecting their efficacy in treating gastrointestinal infections.
Innovation Solution
Development of new polymorphic forms of rifaximin, including Form ζ, η, ι, ι-dry, ι-dry′, and Form B, which exhibit distinct X-ray powder diffraction patterns and thermal properties, allowing for tailored bioavailability and reduced systemic absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional rifaximin formulations are used, then the drug can treat gastrointestinal infections, but systemic absorption occurs leading to bacterial resistance and varying bioavailability
Solution Approach 1:
The patent applies parameter changes by discovering and utilizing different polymorphic forms of rifaximin (Forms ζ, η, ι, ι-dry, ι-dry′, and B), each with distinct crystal structures and physical properties. These polymorphic forms exhibit different dissolution rates and bioavailability profiles, allowing optimization of therapeutic effect while minimizing systemic absorption. The selection of specific polymorphic forms changes the physical parameters of the drug to resolve the contradiction between reliable gastrointestinal action and harmful systemic absorption.
Solution Approach 2:
The patent applies local quality by creating formulations where rifaximin polymorphic forms are distributed and released locally in the gastrointestinal tract. The different polymorphic forms provide localized therapeutic action at the site of infection with minimal systemic circulation. This localized quality ensures high concentration at the target site while reducing harmful systemic exposure that leads to bacterial resistance.
2Reliability
If rifaximin is administered to achieve therapeutic effect, then gastrointestinal infections are treated, but bacterial resistance develops due to systemic absorption
Solution Approach 1:
The patent utilizes parameter changes through the selection of specific polymorphic forms with optimized dissolution characteristics. Forms such as ι-dry and ι-dry′ exhibit controlled dissolution rates that maintain therapeutic concentrations in the gastrointestinal tract while limiting systemic absorption. This parameter optimization ensures reliable therapeutic efficacy against gastrointestinal infections while minimizing the development of bacterial resistance.
Solution Approach 2:
The patent applies blessing in disguise by converting the typically harmful systemic absorption into a beneficial localized action. The polymorphic forms are designed to absorb water and dissolve controllably in the gastrointestinal environment, transforming what would be harmful systemic exposure into beneficial localized therapeutic action. This converts the potential harm of absorption into the benefit of sustained local concentration with minimal resistance development.
3Reliability
If new polymorphic forms are developed, then bioavailability is enhanced and systemic absorption is reduced, but formulation complexity increases
Solution Approach 1:
The patent applies parameter changes by identifying and utilizing naturally occurring polymorphic forms of rifaximin with distinct physical properties. Each polymorphic form (ζ, η, ι, ι-dry, ι-dry′, B) has characteristic X-ray diffraction patterns and dissolution profiles. The selection of specific polymorphic forms optimizes bioavailability parameters without requiring complex formulation technologies, as the polymorphic forms themselves provide the desired release characteristics.
Solution Approach 2:
The patent applies copying by characterizing and replicating the specific X-ray diffraction patterns and physical properties of each polymorphic form. Once a desired polymorphic form is identified, its characteristics are copied and standardized for manufacturing. This allows consistent production of formulations with predictable bioavailability without requiring complex real-time characterization during manufacturing, thus reducing formulation complexity while maintaining reliability.
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 forms of rifaximin offer enhanced bioavailability and reduced systemic absorption, enabling more effective treatment of gastrointestinal infections while minimizing the risk of bacterial resistance.
Implementation Method 1
polymorph Form ζ exhibits an X-ray powder diffraction pattern having characteristic peaks
Implementation Method 2
X-ray powder diffraction pattern having characteristic peaks expressed in degrees 2θ
Data Source
AI summary
The present invention relates to Rifaximin polymorphic forms, to their use in medicinal preparations and to therapeutic methods using them.