Long-acting injectable in situ forming implants: Impact of polymer attributes and API
Xiaoyi Wang1, Ruifeng Wang2, Mckenzie Roy2
1Department of Pharmaceutical Sciences, University of Connecticut, Storrs, CT 06269, USA; State Key Laboratory of Biochemical Engineering, Key Laboratory of Biopharmaceutical Preparation and Delivery (CAS), Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, PR China(1).
This study reveals that Poly(DL-lactide-co-glycolide) (PLGA) properties significantly influence drug release from in situ forming implants. The interplay between drug properties and PLGA characteristics is crucial for predictable drug delivery.
Area of Science:
- Biomaterials Science
- Polymer Chemistry
- Drug Delivery Systems
Background:
- In situ forming implants (ISFIs) based on Poly(DL-lactide-co-glycolide) (PLGA) and N-methyl-2-pyrrolidone (NMP) offer controlled drug release.
- Understanding PLGA's impact on drug release is vital for designing effective implantable drug formulations.
- Previous studies often focused on single drugs, limiting generalizable conclusions about PLGA's influence.
Purpose of the Study:
- To investigate the influence of various Poly(DL-lactide-co-glycolide) (PLGA) properties on drug release kinetics.
- To explore the potential interplay between active pharmaceutical ingredient (API) characteristics and PLGA attributes in in situ forming implants.
- To determine if the drug's physical state (solution vs. suspension) affects polymer interaction and subsequent drug release.
Main Methods:
- Formulation of in situ forming implants using Poly(DL-lactide-co-glycolide) (PLGA) with varied molecular weights, lactic/glycolic acid ratios, and end-cap types.
- Loading of model drugs, naproxen (solution) and meloxicam (suspension), into the PLGA formulations.
- In vitro evaluation of drug release profiles from the developed implants under different PLGA property conditions.
Main Results:
- Minor variations in PLGA molecular weight, lactic/glycolic acid ratio, and blockiness showed consistent effects on both naproxen and meloxicam release.
- The impact of end-cap type (acid vs. ester) and significant changes in the lactic/glycolic acid ratio (e.g., 75/15 to 50/50) on drug release was found to be drug-dependent.
- Naproxen and meloxicam exhibited different release durations from implants made with the same PLGA polymer, highlighting API-specific behavior.
Conclusions:
- Poly(DL-lactide-co-glycolide) (PLGA) properties significantly impact drug release from in situ forming implants, but this effect is modulated by the specific active pharmaceutical ingredient (API).
- The drug's state (solution or suspension) and its intrinsic properties play a critical role in the overall drug delivery performance of PLGA-based implants.
- Developing successful in situ forming implant drug products requires a comprehensive understanding of the complex interplay between polymer attributes and API characteristics.
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