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Biomedical subjects

S H Yuk

Publications and source records attributed to S H Yuk.

6 recordsLinked to original sources
PubMed2004

Hydrophilized poly(lactide-co-glycolide) nanospheres with poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer.

A novel method for preparing the PLGA nanospheres with hydrophilic surface has been designed and characterized. Because of good solubility of tetraglycol in water, PLGA (poly(lactide-co-glycolide)) nanospheres were formed by spraying the PLGA/tetraglycol solution into water. The size of PLGA nanospheres was manipulated by changing the concentration of PLGA/tetraglycol solution. Based on the hydrophobic interaction between PLGA and poly(propylene oxide) domain of F-127 (one of Pluronics, poly(ethylene oxide)-poly(propylene oxide)poly(ethylene oxide) triblock copolymer, F-127-coated PLGA nanospheres was prepared to enhance the stability of PLGA nanospheres in the aqueous media. For the application as a drug delivery vehicle, it was characterized by measuring the loading amount, the encapsulation efficiency and the release pattern of drug. Paclitaxel used as a potent anti-cancer drug was selected as a model drug.

Antineoplastic Agents↗
PubMed2001

Polymeric microspheres composed of pH/temperature-sensitive polymer complex.

A new pH/temperature-sensitive polymer system with transitions resulting both from polymer-water and polymer-polymer interactions has been demonstrated using the mixture of poly(N,N-dimethylamino)ethyl methacrylate (DMAEMA) and polyethyl acrylamide (EAAm). Based on the pH/temperature sensitivity of polymer mixture, the microsphere for pH/temperature-sensitive drug release have been designed and characterized. Hydrocortisone was used as a model drug. This gave the control of hydrocortisone release in an on-off manner without considerable lag time.

Biocompatible Materials↗
PubMed1999

Phase-transition polymers for drug delivery.

Phase-transition polymers show changes in response to external stimuli, such as pH, temperature, light, metabolite, and electric current. Based on the stimuli-induced phase transition, many applications have been developed to improve drug delivery. This paper summarizes various phase-transition polymers and their applications relevant to modulated-drug delivery.

Dose-Response Relationship, Drug↗
PubMed1996

Blood and cell compatibility of gelatin-carrageenan mixtures cross-linked by glutaraldehyde.

Mixtures of gelatin and iota-carrageenan cross-linked by glutaraldehyde were prepared and their physical properties and blood and cell compatibility were compared to gelatin as a control material. According to scanning electron microscopic observation of fracture surfaces, the mixtures were composed of dispersed and continuous domains which might be generated by phase separation of carrageenan. The thermal degradation temperature of iota-carrageenan in the mixtures rose with increasing gelatin content. The swelling process in the mixtures proceeded slower than in gelatin. Tensile strengths of the mixtures, except that containing 50% iota-carrageenan, increased with increased amounts of iota-carrageenan in the mixtures. The iota-carrageenan contents at the surfaces of the mixtures were generally higher than those admixed originally. Static friction coefficients of the mixtures were lower than that of gelatin. Plasma recalcification times of the mixtures were longer than that of gelatin. Platelet adhesion of the mixtures was lower than that of gelatin, while cell adhesion and growth assays using Chinese hamster ovary cells showed that cell adhesion and growth were not dependent on adding iota-carrageenan. It was concluded that blood compatibility of the mixtures increased and cell compatibility did not decrease, compared to gelatin.

Animals↗
PubMedDate not supplied

Microencapsulation of lipid nanoparticles containing lipophilic drug.

A polymeric emulsion bead, which consists of core and capsule, was prepared. The core is composed of lipid nanoparticles containing lipophilic drug and semi-interpenetrating networks (semi-IPNs) are prepared to provide the capsule composed of sodium alginate and hydroxypropylmethyl cellulose (HPMC). The lipid nanoparticles were encapsulated into the polymeric emulsion bead with high drug loading efficiency, and lovastatin was used as a model drug. For the application as an oral drug delivery system, the enteric coating was performed with polymeric emulsion bead. The drug release pattern was controlled by the composition of capsule materials and environmental pH.

Administration, Oral↗