End-Capped VLMW Polymers for Injectable Sustained Release
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Solution Overview
Problem
Existing parenteral sustained release formulations using biodegradable polymers often require organic solvents and viscosity-reducing agents, which can lead to low biocompatibility and stability issues, and difficulty in injection due to high viscosity, necessitating large needles and painful administration.
Innovation Solution
A semi-solid formulation comprising end-capped very low molecular weight biodegradable polymers, such as polylactides or poly(lactide-co-glycolide), without additional solvents or excipients, allowing for continuous release of active substances over a week or more in an aqueous environment, facilitating injection with conventional syringes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If organic solvents and viscosity-reducing agents are added to polymer formulations, then the formulation becomes fluid enough for injection, but biocompatibility and stability are reduced
Solution Approach 1:
The patent changes the molecular weight parameter of the polymer from conventional high molecular weight to very low molecular weight (VLMW), specifically using polymers with molecular weights between 500-5000 Da. This parameter change fundamentally alters the viscosity characteristics, allowing the polymer to be injectable without requiring organic solvents or viscosity-reducing agents, thus maintaining biocompatibility and stability while achieving ease of injection
Solution Approach 2:
The patent creates a composite formulation by combining VLMW polymers with active substances in a specific ratio range (0.1-70% w/w active substance). This composite approach allows the unique properties of VLMW polymers (low viscosity, high fluidity) to enable injection without harmful additives while maintaining the therapeutic function of the active substance
2Duration of action of moving object
If high molecular weight biodegradable polymers are used for sustained release, then release duration is extended, but viscosity increases making injection difficult
Solution Approach 1:
The patent fundamentally changes the molecular weight parameter from high to very low (500-5000 Da), which paradoxically allows both sustained release and injectability. The VLMW polymers have sufficiently long polymeric chains to provide sustained release through degradation control while having low enough molecular weight to maintain fluidity and enable injection with conventional syringes without heating or special devices
3Ease of operation
If very low molecular weight polymers are used, then viscosity is reduced improving injectability, but release duration is shortened
Solution Approach 1:
The patent applies local quality control by precisely controlling the molecular weight distribution within the 500-5000 Da range and the active substance content within 0.1-70% w/w. This localized parameter control ensures that the polymer chains are long enough to provide sustained release through controlled degradation while remaining short enough to maintain low viscosity and high fluidity for easy injection
Solution Approach 2:
The patent changes the molecular weight parameter to a specific very low range (500-5000 Da) and controls the active substance concentration parameter (0.1-70% w/w). These parameter changes create an optimal balance where the polymer degrades slowly enough for sustained release (at least one week) while maintaining sufficiently low viscosity for injection with conventional syringes
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 stable and prolonged release of active substances, improving biocompatibility and ease of administration, enabling the use of conventional syringes and thinner needles, and maintaining stability and effectiveness over extended periods.
Implementation Method 1
a) An end-capped modified very low molecular weight biodegradable end-capped polymer
Implementation Method 2
when the semi-solid is placed in an aqueous physiological environment
Data Source
AI summary
The present invention relates to a parenteral, sustained and controlled release, semisolid formulation comprising an end-capped oligomer and at least one active substance without any supplementary viscosity reducing agent or excipient.