Synthesis and characterization of mPEG-PCL copolymers as a polymersomes for delivery of enalapril as a model hydrophilic drug

Document Type: Research Paper


Zanjan Pharmaceutical Nanotechnology Research Center, Zanjan University of Medical Sciences, Zanjan, Iran; Department of Medicinal Chemistry, School of Pharmacy, Zanjan University of Medical Sciences, Postal code 45139-56184, Zanjan, Iran



Purpose: Enalapril maleate (EPM), was used for hypertension and congestive heart failure. In this way, an innovative delivery system with mPEG–PCL was synthesized and the release profile of the EPM from the drug-loaded polymersomes was evaluated.
Methods: Di-block methoxy)-poly (ethylene glycol) - Poly (caprolactone) (mPEG-PCL) copolymers were synthesized and used to prepare of polymersomes for controlled release of EPM as hydrophilic model drug. MPEG-PCL copolymer was characterized in vitro by HNMR, FTIR, DSC and GPC techniques. The resulting polymersomes were characterized further by various techniques such as dynamic light scattering (DLS) and transmission electron microscopy (TEM).
Results: The results of TEM shows the polymersomes formed had spherical structure and the size of nanoparticles is 80 nm. The loading and encapsulation efficiency of EPM were determinate by HPLC at 215 nm with loading and encapsulation efficiency 19.8% ± 2.12% and 85.6% ± 1.26%, respectively. Study on DSC results exposed strong interaction between EPM and copolymer. In vitro release of EPM from polymersomes was clearly sustained in all the time tested for this purpose. The sustained release of drug was hypothetically due to the entrapment of EPM in core of polymersomes. Polymersomes also showed acceptable stability for long periods of time.
Conclusion: The results indicate the successful formulation of EPM loaded m-PEG/PCL polymersomes. Overall, the results was showed that m-PEG-PCL polymersomes can be considered as a promising carrier for hydrophilic drugs such as EPM.


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