Study on Drug Release Behaviors of Poly-α,β-[N-(2-hydroxyethyl)-l-aspartamide]-g-poly(ε-caprolactone) Nano- and Microparticles

Abstract

Biodegradable amphiphilic graft copolymers poly-alpha,beta-[N-(2-hydroxyethyl)-L-aspartamide]-g-poly(epsilon-caprolactone) (PHEA-g-PCL) with different branch lengths were synthesized through the ring-opening polymerization of epsilon-caprolactone initiated by the macroinitiator PHEA bearing hydroxyl groups. With use of the graft copolymers with different compositions, nanoparticle drug delivery systems with sizes smaller than 100 nm were prepared by a dialysis method, and microparticle drug delivery systems with sizes smaller than 5 microm were fabricated by a melting-emulsion method. The regularly spherical shapes of the drug-loaded nano- and microparticles were verified by transmission electron microscopy and scanning electron microscopy. In vitro drug release properties of nano- and microparticle drug delivery systems were investigated, with the emphasis on the effects of polymer composition, particle size, and drug-loading content on the release behaviors.

Analytical methods for dissolution testing of nanosized drugs

“…Hence this technique is more common for dosage forms with long-term release, like implants, stents or injectable long-life nanoparticles. [31] Nevertheless, there are reports of dialysis methods, like the dialysis bag, for dissolution testing of instant-release dosage forms. [32] Also other studies exist in which dialysis was established successfully.…”

“…A disadvantage is the long equilibrium time needed by the API to diffuse through the dialysis membrane. Hence this technique is more common for dosage forms with long‐term release, like implants, stents or injectable long‐life nanoparticles [31] . Nevertheless, there are reports of dialysis methods, like the dialysis bag, for dissolution testing of instant‐release dosage forms [32] .…”

Early stage release control of an anticancer drug by drug-polymer miscibility in a hydrophobic fiber-based drug delivery system

“…In eqn (7), the exponent 'n' has been used to explain the release mechanisms for different matrix geometries. 26,43,44 For example, n for the Fickian release from slabs, cylinders and spheres are 0.50, 0.45 and 0.43, respectively, and those for zeroorder release from non-swelling system is 1.…”

Core/shell pH‐sensitive micelles self‐assembled from cholesterol conjugated oligopeptides for anticancer drug delivery

“…It is well known that micelles have core/shell architecture that is composed of hydrophobic segments as internal core, providing a loading space for hydrophobic drugs, and hydrophilic segments as surrounding corona in aqueous medium, affecting the drug release behaviors 19–21. Especially, the environmentally sensitive micelles were investigated as smart drug delivery systems for cancer therapy 22–28. For example, Bae's group has developed a pH‐sensitive carrier micelle self‐assembled from poly(His‐ co ‐Phe)‐ b ‐poly(ethylene glycol) and poly( L ‐lactic acid)‐ b ‐poly(ethylene glycol) 14.…”