Copolymers of -caprolactone and L-lactide (PCLLA) with different monomer ratio were synthesized by ring opening polymerization, and drug-loaded nanoparticles of poly--caprolactone (PCL), poly-L-lactide (PLLA), and their copolymers were prepared by precipitation method, respectively. The results of d
Preparation and characterization of enalapril maleate–loaded nanoparticles using amphiphilic diblock copolymers
✍ Scribed by Youngtai Yoo; Dong-Chul Kim; Tae-Yoon Kim
- Publisher
- John Wiley and Sons
- Year
- 1999
- Tongue
- English
- Weight
- 212 KB
- Volume
- 74
- Category
- Article
- ISSN
- 0021-8995
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✦ Synopsis
Nanoparticles with the dimensions of circa 50 nm prepared from the micellar aggregation of diblock copolymers of poly(ethylene oxide) and polycaprolactone (PEO-b-PCL) were explored as a parenteral carrier system for water-soluble organic drugs in salt form. Enalapril maleate (EPM), developed for hypertension and congestive heart failure, was used as a model drug. The nanoparticles from three block copolymers with compositions of 5k-7.5k, 5k-5k, and 5k-2.5k (PEO-b-PCL) exhibited drugloading efficiency of 38%, 47%, and 26%, respectively, for an equivalent amount of EPM in a 1% (w/v) micelle solution. Particularly, 5k-5k micelles could be incorporated with the model drug up to 47% (w/w) of polymer. Furthermore, these nanoparticles possess drug-retaining capability at 25°C or below even after free EPM was eliminated from the aqueous phase by dialysis. A temperature-responsive release behavior was displayed upon heating to the physiological temperature, 37°C. Drug release from the micelles proceeded in a fairly linear fashion for a duration of about 4 -7 days, depending on the composition of the block copolymers. Daily average fractional release was consistent regardless of drug contents in the nanoparticles. In a preliminary animal toxicity test the EPM-loaded micelle solutions were intravenously administered to mice of the ICR strain through the tail vein. The animal subjects received 0.7 mL of EPM micelle solution up to six times and showed normal weight gain and food consumption.
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Amphiphilic diblock copolymers of polyvinyl alcohol (PVA) and polystyrene (PS), which are very difficult to prepare by common polymerization methods, have been obtained by initiation of the polymerization of styrene and vinyl acetate successively, followed by hydrolysis, using the ethanolamine-benzo
## Abstract Core–shell type nanoparticles of poly(L‐lactide)/poly(ethylene glycol) (LE) diblock copolymer were prepared by a dialysis technique. Their size was confirmed as 40–70 nm using photon correlation spectroscopy. The ^1^H‐NMR analysis confirmed the formation of core–shell type nanoparticles