tPA Formulation Stability at Room Temperature

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Solution Overview

Problem

Recombinant tissue-type plasminogen activator (tPA) formulations face challenges with poor long-term stability at room temperature, leading to degradation and instability in liquid form, which complicates storage and administration, especially for catheter use.

Innovation Solution

A novel liquid composition comprising 0.15 to 0.25 units/mL tPA, 1 mM to 10 mM tranexamic acid, 2.5 to 5.0% sucrose, and optional nonionic surfactant and pH buffering agents, with a pH of 6.0 to 8.0, allowing for stable storage and use at room temperature, and an essentially water-free composition by lyophilization for enhanced stability and convenience.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If recombinant tPA is formulated as a liquid solution, then it can be readily administered and used, but it exhibits poor long-term stability and degradation at room temperature

Engineering Contradiction:
Improvereadiness for administrationVSAvoidlong-term stability at room temperature
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent applies parameter changes by optimizing the pH range (6.0-8.0) and incorporating specific excipients including sucrose (2.5-5.0% w/v), tranexamic acid (1-10 mM), and optional nonionic surfactants at controlled concentrations (0.01-0.1% w/v). These parameter adjustments enable the liquid formulation to maintain stability at room temperature while remaining ready for administration, resolving the contradiction between ease of use and compositional stability.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If recombinant tPA is stored in lyophilized form, then it maintains stability at refrigerated temperatures, but it requires reconstitution immediately before use and cannot be stored at room temperature

Engineering Contradiction:
Improvestorage stabilityVSAvoidreconstitution time and storage flexibility
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The invention changes the physical and chemical parameters of the formulation by incorporating stabilizing excipients (sucrose, tranexamic acid, nonionic surfactants) and maintaining pH between 6.0-8.0, which allows the tPA to remain stable in liquid form at room temperature without requiring lyophilization or refrigeration, thereby eliminating reconstitution steps and storage time losses.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If the concentration of tPA is increased for effective catheter treatment, then clot lysis activity is improved, but stability and handling become more difficult

Engineering Contradiction:
Improveclot lysis activityVSAvoidformulation stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent creates a composite formulation system combining tPA with multiple stabilizing components: sucrose (2.5-5.0% w/v) as a stabilizer, tranexamic acid (1-10 mM) to prevent fibrinogen degradation, and nonionic surfactants (0.01-0.1% w/v) to prevent aggregation. This composite approach allows higher tPA concentrations to be maintained stably in liquid form, ensuring reliable clot lysis activity while maintaining formulation stability and ease of handling.

Inventive Principle:
Principle #40Composite materials

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 formulation provides a stable and effective tPA solution for treating occluded catheters, maintaining clot lysis activity and stability during storage and handling, enabling direct instillation into catheters without the need for refrigeration, thus improving handling and storage conditions.

Implementation Method 1

about 2.5 to 5.0% (w/v) sucrose

Methodology Applied
Scientific EffectPreferential exclusion:

Implementation Method 2

about 1 mM to 10 mM tranexamic acid

Methodology Applied
Scientific EffectEnzyme inhibition:

Implementation Method 3

optional nonionic surfactant

Methodology Applied
Scientific EffectSteric stabilization: Surfactant

Implementation Method 4

pH buffering agents, with a pH of 6.0 to 8.0

Methodology Applied
Scientific EffectpH buffering:

Data Source

PatentUS20230310717A1Tissue plasminogen activator formulation
Publication Date: 2023.10.05 CHIESI FARMACEUTICI SPA

AI summary

The present disclosure relates to stable formulations of tissue-type plasminogen activator (tPA). In particular, the disclosure relates to specific new formulations, methods of preparing them and methods of using them.