ABSTRACT
Profiles of alkyl homologues and isomers of LAS were monitored for an urban stream polluted with municipal wastewaters in Korea. Alkylchains of the stream LAS were shorter than commercial standards and higher I/E ratios were associated with lower LAS concentrations. These suggested a partial biodegradation of LAS in the stream. Higher LAS concentrations were observed in the upper stream. LAS levels were at their lowest during summer probably due to high precipitation and faster biodegradation rates. LAS contributed to about 29% of MBAS and could be used to roughly estimate BOD concentration of the stream.
ABSTRACT
Five novel dexamethasone 21-oic acid derivatives (DM-I, II, IV, V and VI) were prepared from dexamethasone in accordance with the antedrug concept and their local anti-inflammatory activities and systemic untoward effects were evaluated through steroid receptor binding study, cotton pellet granuloma bioassay and acute pharmacological studies. The acetonide derivatives, DM-V and DM-VI, were found to possess much stronger affinities to glucocorticoid receptors than the acid ester derivatives, DM-I and DM-II, in vitro. In in vivo experiments, locally applied DM-V and DM-VI exerted potent inhibitory activity against granuloma formation; DM-I and DM-II also produced moderate granuloma inhibitory activity in spite of their weak affinity to the receptors. DM-II, DM-V and DM-VI manifested less systemic effects than dexamethasone, prednisolone and DM-I, such as thymus involution, suppression of plasma corticosterone and gluconeogenesis in the liver. Among the five compounds, DM-V could be exemplified as a potentially useful antedrug for topical or local application, since it has anti-inflammatory potency approaching that of the more traditional steroid prednisolone, but it does not have the systemic adverse effects.