Related Experiment Video
Updated: Jan 5, 2026

Multi-Scale Modification of Metallic Implants With Pore Gradients, Polyelectrolytes and Their Indirect Monitoring In vivo
Published on: July 1, 2013
Effect of Polymer Permeability and Solvent Removal Rate on In Situ Forming Implants: Drug Burst Release and
Xiaowei Zhang1,2, Liqun Yang3, Chong Zhang4
1Department of Pharmaceutics, School of Pharmacy, China Medical University, Liaoning 110122, China. sally00125@163.com.
Abstract:
To explore the mechanism of drug release and depot formation of in situ forming implants (ISFIs), osthole-loaded ISFIs were prepared by dissolving polylactide, poly(lactide-co-glycolide), polycaprolactone, or poly(trimethylene carbonate) in different organic solvents, including N-methyl-2-pyrrolidone (NMP), dimethyl sulfoxide (DMSO), and triacetin (TA). Drug release, polymer degradation, solvent removal rate and depot microstructure were examined. The burst release effect could be reduced by using solvents exhibit slow forming phase inversion and less permeable polymers. Both the drug burst release and polymer depot microstructure were closely related to the removal rate of organic solvent. Polymers with higher permeability often displayed faster drug and solvent diffusion rates. Due to high polymer-solvent affinity, some of the organic solvent remained in the depot even after the implant was completely formed. The residual of organic solvent could be predicted by solubility parameters. The ISFI showed a lower initial release in vivo than that in vitro. In summary, the effects of different polymers and solvents on drug release and depot formation in ISFI systems were extensively investigated and discussed in this article. The two main factors, polymer permeability and solvent removal rate, were involved in different stages of drug release and depot formation in ISFI systems.
Related Concept Videos
Factors Affecting Dissolution: Drug Permeability, Stability and Stereochemistry
Factors Affecting Dissolution: Polymorphism, Amorphism and Pseudopolymorphism
Some polymorphic crystals possess lower aqueous solubility than their amorphous counterparts, leading to incomplete absorption. For instance, the oral suspension of Chloramphenicol, which...
Factors Influencing Drug Absorption: Pharmaceutical Parameters
In Vitro Drug Dissolution: Alternative Methods
Factors Affecting Dissolution: Particle Size and Effective Surface Area

