Preparation and in vitro release of total alkaloids from alstonia scholaris leaf-loaded mPEG-PMA microspheres

Abstract

The total alkaloids extracted from the leaves of Alstonia scholaris (ASAs) have been reported to reduce fever, remove phlegm, and relieve coughs. However, their drug half-lives are short. Thus, to obtain sustained-release preparations of total alkaloids from ASAs, mandelic acid oxyanhydride (mandelic acid OCA) was synthesized by the reaction of L-mandelic acid (MA) with triphosgene, and subsequent copolymerization with polyethylene glycol monomethyl ether (mPEG) of different molecular weights yielded the corresponding mPEG poly-MA (mPEG-PMA) copolymers. ASAs-loaded microspheres were then prepared using the double emulsion method, and their in vitro release (15 d, 37 °C) and in vitro degradation behaviors were studied. The morphology, size, embedding efficiency, and drug loading efficiency were investigated for the prepared microspheres, and screening was carried out using the mPEG10K-PMA drug-loaded microspheres to analyze their biological characteristics. Anti-inflammatory experiments using Kunming mice and Sprague Dawley rats showed that the microspheres exhibited good anti-inflammatory properties. Moreover, the ASAs-loaded microspheres exhibited a good biocompatibility, and the hemolysis rate was <5%.

Inhalable microparticles as drug delivery systems to the lungs in a dry powder formulations

“…These agents could be, e.g. bacteriophages—viruses that exclusively target bacteria [ 100 ], curcumin, a natural food coloring factor with anti-inflammatory properties that is also a quorum sensing inhibitor [ 101 , 102 ], or other anti-inflammatory substances of natural origin such as Alstonia scholaris alkaloids in an interesting copolymer of PEG and poly(mandelic acid) [ 103 ]. The delivery of bacteriophages to the lungs by Agarwal et al .…”