Search PubMed⌕ Search
Home/Archive/PubMed

PubMed · 10696447

Temperature-sensitive aqueous microgels.

R Pelton
View original source ↗Export metadata ↓

Abstract

An account of the preparation and characterization of temperature-sensitive aqueous microgels based on poly(N-isopropylacrylamide) was first published in 1986. Since then there has been a steady increase in the number of publications describing preparation, characterization and applications of temperature-sensitive microgels. This paper reviews the important developments in the area of temperature-sensitive aqueous microgels over the last decade. Although most of the work involves gels based on poly(N-isopropylacrylamide), other polymers are also considered. Core-shell latex particles exhibiting temperature-sensitive properties are also described.

Explore related subjects

Acrylic ResinsAdsorptionChemical PhenomenaChemistry, PhysicalColloidsElectric ConductivityEnzymes, ImmobilizedGelsGranulocytesHumansMaterials TestingParticle SizePolymersRheologySolubilitySolventsTemperatureWatergamma-GlobulinsJournal ArticleResearch Support, Non-U.S. Gov'tReview

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

R Pelton. 2000-02-01. Temperature-sensitive aqueous microgels.. https://doi.org/10.1016/s0001-8686(99)00023-8

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2000

Mucoadhesive drug carriers based on complexes of poly(acrylic acid) and PEGylated drugs having hydrolysable PEG-anhydride-drug linkages.

We have designed a new mucoadhesive drug delivery formulation based on H-bonded complexes of poly(acrylic acid) (PAA) or poly(methacrylic acid) (PMAA) with the poly(ethylene glycol) (PEG), of a (PEG)-drug conjugate. The PEGylated prodrugs are synthesized with degradable PEG-anhydride-drug bonds for eventual delivery of free drug from the formulation. In this work we have used indomethacin as the model drug which is PEGylated via anhydride bonds to the PEG. The complexes are designed first to dissociate as the formulation swells in contact with mucosal surfaces at pH 7.4, releasing PEG-indomethacin, which then hydrolyses to release free drug and free PEG. We found that as MW of PAA increases, the dissociation rate of the complex decreases, which results in decreased rate of release of the drug. On the other hand, the drug release from PEG-indomethacin alone and from solid mixture of PEG-indomethacin+PAA was much faster than that from the H-bonded complexes. Due to the differences in the thermal stability, PMAA complex exhibited slightly faster drug release than that of the PAA complex of comparable MW. These H-bonded complexes of degradable PEGylated drugs with bioadhesive polymers should be useful for mucosal drug delivery.

Acrylic Resins↗
PubMed2000

Enantiomeric separations of cationic and neutral compounds by capillary electrochromatography with monolithic chiral stationary phases of beta-cyclodextrin-bonded negatively charged polyacrylamide gels.

Enantiomeric separation by capillary electrochromatography with beta-cyclodextrin-bonded negatively charged polyacrylamide gels was examined. The columns used are capillaries filled with a negatively charged polyacrylamide gel, a so-called monolithic stationary phase, to which allyl carbamoylated beta-CD (AC-beta-CD) derivatives covalently bind. The capillary wall is activated first with a bifunctional reagent to make the resulting gel bind covalently to the inner surface of the fused-silica tubing. Enantiomeric separations of 15 cationic compounds were achieved using the above-mentioned columns and mobile phases of 200 mmol l(-1) Tris-300 mmol I(-1) boric acid buffer (pH 7.0 or 9.0) or 200 mmol l(-1) Tris-300 mmol l(-1) boric acid buffer (pH 7.0) containing an achiral crown ether (18-crown-6). Enantiomeric separations of two neutral compounds were also achieved using 200 mmol l(-1) Tris-300 mmol l(-1) boric acid buffer (pH 9.0) as a mobile phase. High efficiencies of up to 150,000 plates m(-1) were obtained. Both the within- and between-run reproducibilities of retention time and separation factor were good. The reproducibilities of retention time and separation factor for three different columns prepared from a different batch of monomers were acceptable. The gel-filled capillaries were stable for at least 3 months with intermittent use, utilizing the mobile phase of 200 mmol I(-1) Tris-300 mmol I(-1) boric acid buffer (pH 9.0).

Acrylic Resins↗
PubMed2000

Organic esters of plasticizers affecting the water absorption, adhesive property, glass transition temperature and plasticizer permanence of eudragit acrylic films.

The materials used in film coating technology are very important tools for pharmaceutical applications. The effects of four organic esters used as plasticizers (triacetin, diethyl phthalate (DEP), dibutyl phthalate (DBP) and tributyl citrate (TBC)) on the water absorption behavior and adhesive property of Eudragit films and on the glass transition temperature (T(g)) and plasticizer permanence of Eudragit E film were investigated. The results indicate that the water absorption of these Eudragit films was dependent on the type of Eudragit polymers and plasticizers used. Eudragit E film plasticized with triacetin showed a slight water absorption, but when plasticized with DEP, DBP or TBC did not. All Eudragit RL films showed significant uptake of water, but Eudragit RS films exhibited a lesser degree of water absorption. The adhesion (tack value) of all Eudragit films was markedly increased when the concentration of plasticizer was greater than 25%. Eudragit E film exhibited a greater adhesiveness than the Eudragit RL or RS film, particularly with higher plasticizer concentration. Weight loss of the Eudragit E film plasticized with triacetin or DEP was more pronounced with aging, but when plasticized with DBP or TBC weight loss was not seen. The results indicate that TBC may be the best choice of plasticizer for Eudragit film, particularly for the Eudragit E film.

Acrylic Resins↗