Biomedical subjects

N Yan

Publications and source records attributed to N Yan.

23 records · Page 2Linked to original sources

PubMed1989

Experimental and clinical investigation on oxiconazole.

A new antimycotic imicazole drug, oxiconazole, used both in vitro and in vivo in the treatment of 212 cases of tinea corporis, tinea cruris and tinea pedis is reported. In vitro, it shows marked antimycotic effect against 24 strains of pathogenic fungi except those of Wangiella dermatitides and 3 strains of Aspergilli. The minimal inhibition concentration (MIC) to Epidermophyton floccosum and Candida guilliermondi are 1 microgram/ml and 0.5 microgram/ml. The cure rate of 2% cream of oxiconazole in 124 cases of tinea corporis and tinea cruris is 90.3%, and in 88 cases of tinea pedis, 89.78%.

Adolescent↗

PubMedDate not supplied

Preparation and properties of polyurea microcapsules with non-ionic surfactant as emulsifier.

Polyurea microcapsules containing oily substances were prepared by using cyanate and polyamine as the monomers with non-ionic surfactant as the emulsifiers. Results showed that TDI-DETA microcapsules had the best stability. The mean diameter decreased and the size distribution curves became narrower and sharper as the stirring speed and the emulsifier concentration during emulsification increased. Addition of Tween 80 to aqueous solution containing OP led to an increase in microcapsule diameter and wider distribution of microcapsules due to the changes in interfacial tension. The isoelectric point of the polyurea microcapsules was found to be pH 5.8.

Capsules↗

PubMedDate not supplied

Study on polyamide microcapsules containing oily liquids.

Oily liquids were microencapsulated within polyphthalamide membranes with dodecyl sulphonate sodium (DSS) as an emulsifier. The mean diameter and the distribution, as well as the zeta-potential, of the microcapsules were analysed. It was found that the mean diameter decreases with an increase in stirring speed and emulsifier concentration during the emulsification step. The addition of DSS to aqueous phase resulted in a decrease in zeta-potential of the microcapsules.

Capsules↗

PubMedDate not supplied

Effect of operation variables and monomers on the properties of polyamide microcapsules.

Oil containing microcapsules were prepared by using phthaloyl dichloride as an oil-soluble monomer and diethylene triamine (DETA) as a water-soluble monomer. The diameter of the microcapsules decreased and their distribution became narrower and sharper as the emulsifying time was increased within the initial period of 45 s, beyond which no appreciable changes in the diameter and its distribution were observed. Once DETA was introduced into the aqueous solution to initiate the interfacial polycondensation reaction, reducing the stirring speed diminished the formation of the membrane fragments, but resulted in an increase in the microcapsule diameter. This indicates that the strength of the initial membrane is not strong enough to prevent the microcapsules from coalescing. Raising the volume fraction of the dispersed phase led to a larger diameter and a wider distribution of the microcapsules. When ortho-, meta- or para-phthaloyl dichloride was used as the oil-soluble monomer, both the diameter and the zeta-potential of the microcapsules decreased in the order: ortho-->meta-->para-, indicating that the steric effect of the monomers plays an important role in the microencapsulation process.

Capsules↗

PubMedDate not supplied

A study of the stability of W/O/W multiple emulsions.

The stability of W/O/W emulsions has been studied in batch agitators. The surfactants suitable for W/O/W emulsions were screened and the factors affecting the emulsion stability were also studied. Results showed that polyamine E644 was an excellent emulsifier for W/O emulsions since the emulsion stabilized by it has not only good stability but also shows smaller swelling. The stability of the emulsion increases with increase in membrane viscosity and concentration of surfactant, but decreases with increase in concentration of the internal reagent in the internal phase and the carriers in the membrane. Raising the agitation speed and the time for preparing the W/O emulsion is beneficial to membrane stability due to formation of smaller internal droplets, but raising the speed for dispersing the W/O emulsion in the external phase results in an increase in membrane breakage.

Chemistry, Pharmaceutical↗