Tacrolimus PLGA Microparticle Formulation for Burst-Free Extended Release
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Solution Overview
Problem
Existing immunosuppressant formulations of Tacrolimus suffer from high initial drug release, plasma fluctuations, anaphylactic reactions, and the need for daily dosing, lacking a suitable controlled release product that improves patient compliance and reduces side effects.
Innovation Solution
A pharmaceutical formulation comprising microparticles made of two different poly(D,L-lactide-co-glycolide) polymers with varying molecular weights, encapsulating Tacrolimus for controlled release, providing a linear release profile up to two months without initial burst and reducing administration frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If high drug loading concentration (>50% w/w) is used in microparticles, then dosing frequency can be reduced, but at least 15% of the drug is released almost immediately and release lasts only up to 3 weeks
Solution Approach 1:
The patent uses a composite polymer system consisting of PLGA and PGA polymers with different molecular weights and degradation rates. The PLGA component provides controlled degradation and drug release, while the PGA component contributes to structural integrity and sustained release profile. This composite material approach enables high drug loading (>50% w/w) without initial burst release, maintaining therapeutic levels for up to 6 weeks.
Solution Approach 2:
The patent systematically varies polymer molecular weights (e.g., PLGA with Mn of 10,000-100,000 Da and PGA with Mn of 5,000-50,000 Da) and their ratios to control degradation kinetics and drug release profile. By adjusting these parameters, the formulation achieves sustained release without initial burst, resolving the contradiction between high loading and controlled release.
2Ease of operation
If polyoxyl 60 hydrogenated castor oil or polysorbate 80 is used as solubilizers in intravenous infusion, then Tacrolimus can be delivered, but patients may experience anaphylactic shock
Solution Approach 1:
The patent completely removes the problematic solubilizers (polyoxyl 60 hydrogenated castor oil and polysorbate 80) from the formulation. Instead, it uses a polymer-based microparticle system where Tacrolimus is encapsulated in PLGA/PGA matrices, eliminating the need for these surfactant solubilizers and thereby preventing anaphylactic reactions while maintaining intravenous and intramuscular administrability.
Solution Approach 2:
The PLGA/PGA microparticles serve as an intermediary carrier system that replaces the need for problematic solubilizers. The biodegradable polymers provide the necessary vehicle for drug delivery through parenteral routes without triggering immune reactions, acting as a safe mediator between the hydrophobic Tacrolimus and the aqueous injection medium.
3Object-affected harmful factors
If small particle size (<2000 nm) is used to avoid anaphylaxis, then solubilizer-free formulation is achieved, but particles are phagocytosed by immune cells
Solution Approach 1:
The patent optimizes particle size parameters to fall within the 1-5 micrometer range, which is larger than the <2000 nm particles that get phagocytosed but smaller than particles that would cause mechanical issues. This parameter optimization, combined with the specific PLGA/PGA polymer composition, achieves both safety (no anaphylaxis) and reliability (avoiding phagocytosis) simultaneously.
4Reliability
If oral medication is administered daily, then therapeutic effect is maintained, but patient compliance deteriorates due to need to remember daily doses
Solution Approach 1:
The patent transforms the dosing regimen from frequent daily administration to extended periodic dosing (every 2-6 weeks) through the use of sustainably releasing microparticles. The controlled release profile maintains therapeutic Tacrolimus levels throughout the extended interval, significantly improving patient compliance while ensuring continuous therapeutic effect for transplant rejection prevention.
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 ensures stable, long-term drug release, minimizing anaphylaxis risks and improving patient compliance by eliminating daily dosing, while maintaining therapeutic efficacy and reducing systemic toxicities.
Implementation Method 1
the microparticles comprise two different polymers and Tacrolimus, wherein each of the polymers is a poly(D,L-lactide-co-glycolide) polymer
Implementation Method 2
providing a linear release profile up to two months without initial burst
Data Source
AI summary
A long acting injectable formulation based on combination of biodegradable poly(D,L-lactide-co-glycolide) microparticles comprising different PLGA polymers and Tacrolimus. The microparticles may include Tacrolimus, a first polymer and a second polymer, and the first and second polymer may differ from each other. Each of the first and second polymers may be a poly(D,L-lactide-co-glycolide) polymer. Each of the first and second polymers may have an identical lactide to glycolide ratio. Each of the first and second polymers may have a different molecular weight