(R)-Oxybutynin Hydrochloride Polymorphs for Stable Pharmacokinetics

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Solution Overview

Problem

Existing oxybutynin formulations lack stability and efficacy due to variations in crystalline forms, which affect their pharmacokinetic properties and therapeutic outcomes.

Innovation Solution

Development of three distinct polymorphic forms (A, B, and C) of (R)-oxybutynin hydrochloride, characterized by unique X-ray powder diffraction patterns and thermal stability, to enhance stability and therapeutic efficacy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional oxybutynin formulations are used, then they can be administered orally or topically, but they lack stability and have variable efficacy due to crystalline form variations

Engineering Contradiction:

ImprovestabilityVSAvoidcrystalline form consistency

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent applies parameter changes by systematically varying crystallization conditions including solvent type (isopropanol, toluene, heptane, MIBK), temperature (0°C to 25°C), and pH (using different acids like HCl, HBr, HI, HF) to obtain distinct polymorphic forms with consistent and reproducible properties

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent utilizes phase transitions through controlled crystallization processes where oxybutynin hydrochloride transitions from solution phase to solid crystalline phase under specific conditions, forming distinct polymorphic forms (Forms A, B, and C) with unique XRPD patterns and stable compositional characteristics

Inventive Principle:

Principle #36Phase transitions

2Reliability

If conventional oxybutynin formulations are used, then they can treat overactive bladder and smooth muscle spasms, but their therapeutic efficacy varies due to inconsistent pharmacokinetic properties

Engineering Contradiction:

Improvetherapeutic efficacyVSAvoidpharmacokinetic consistency

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces mechanical mixing or conventional formulation methods with a chemically controlled crystallization system where specific acid-base reactions and solvent-solute interactions dictate the formation of consistent polymorphic forms, thereby ensuring reproducible pharmacokinetic properties

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 provide improved stability and therapeutic efficacy by maintaining consistent pharmacokinetic properties, facilitating controlled release and enhancing bioavailability.

Implementation Method 1

X-ray powder diffraction patterns

Methodology Applied

Scientific EffectX-ray powder diffraction: X-Ray

Implementation Method 2

X-ray powder diffraction patterns

Methodology Applied

Scientific EffectDiffraction: Diffraction

Implementation Method 3

Thermal analysis of the (R)-oxybutynin HCl Form A polymorph by TGA (top) and DSC (bottom)

Methodology Applied

Scientific EffectThermal analysis:

Implementation Method 4

Thermal analysis of the (R)-oxybutynin HCl Form A polymorph by TGA (top) and DSC (bottom)

Methodology Applied

Scientific EffectThermogravimetric analysis:

Implementation Method 5

Thermal analysis of the (R)-oxy butynin HCl Form A polymorph by TGA (top) and DSC (bottom)

Methodology Applied

Scientific EffectDifferential scanning calorimetry:

Data Source

PatentUS12448347B2Polymorphic forms of (R)-oxybutynin hydrochloride

Publication Date: 2025.10.21 APNIMED INC (DELAWARE)

AI summary

Polymorphic forms of (R)-oxybutynin HCl, including three crystalline forms, are prepared and characterized. Uses of the various polymorphic forms of (R)-oxybutynin HCl for Obstructive Sleep Apnea (OSA) treatment are also disclosed.