Impacts of Coastal Development on the Ecology of Tidal Creek Ecosystems of the US Southeast including Consequences to Humans

Upland areas of southeastern U.S. tidal creek watersheds are popular locations for development, and they form part of the estuarine ecosystem characterized by high economic and ecological value. The primary objective of this work was to define the relationships between coastal development, with its concomitant land use changes and associated increases in nonpoint source pollution loading, and the ecological condition of tidal creek ecosystems including related consequences to human populations and coastal communities. Nineteen tidal creek systems, located along the southeastern United States coast from southern North Carolina to southern Georgia, were sampled during summer, 2005 and 2006. Within each system, creeks were divided into two primary segments based upon tidal zoning: intertidal (i.e., shallow, narrow headwater sections) and subtidal (i.e., deeper and wider sections) and then watersheds were delineated for each segment. Relationships between coastal development, concomitant land use changes, nonpoint source pollution loading, the ecological condition of tidal creek ecosystems, and the potential impacts to human populations and coastal communities were evaluated. In particular, relationships were identified between the amount of impervious cover (indicator of coastal development) and a range of exposure and response measures including increased chemical contamination of the sediments, increased pathogens in the water, increased nitrate/nitrite levels, increased salinity range, decreased biological productivity of the macrobenthos, alterations to the food web, increased flooding potential, and increased human risk of exposure to pathogens and harmful chemicals. The integrity of tidal creeks, particularly the headwaters or intertidally-dominated sections, were impaired by increases in nonpoint source pollution associated with sprawling urbanization (i.e., increases in impervious cover). This finding suggests these habitats are valuable early warning sentinels of ensuing ecological impacts and potential public health and flooding risk from sprawling coastal development. Results also validate the use of a conceptual model with impervious cover thresholds for tidal creek systems in the southeast region.

Best practices for the development, scale-up, and post-approval change control of IR and MR dosage forms in the current quality-by-design paradigm

In this whitepaper, the Manufacturing Technical Committee of the Product Quality Research Institute provides information on the common, best practices in use today in the development of high-quality chemistry, manufacturing and controls documentation. Important topics reviewed include International Conference on Harmonization, in vitro-in vivo correlation considerations, quality-by-design approaches, process analytical technologies and current scale-up, and process control and validation practices. It is the hope and intent that this whitepaper will engender expanded dialog on this important subject by the pharmaceutical industry and its regulatory bodies.

The effects of novel cathepsin E inhibitors on the big endothelin pressor response in conscious rats

The aspartic protease, cathepsin E, has been shown to specifically cleave big endothelin (big ET-1) at the Trp21-Val22 bond to produce endothelin (ET-1) and the corresponding C-terminal fragment. To determine whether cathepsin E is a physiologically relevant endothelin converting enzyme (ECE), three novel and potent inhibitors of cathepsin E were administered to conscious rats prior to a pressor challenge with big ET-1. One of the inhibitors of cathepsin E, SQ 32,056 (3 mg/kg i.v.), blocked the big ET-1 response. However, this dose of SQ 32,056 also blocked the pressor response to ET-1. Phosphoramidon specifically inhibited the Big ET-1 pressor response. These results suggest that ECE is not cathepsin E.

Determination of chlorprothixene and its sulfoxide metabolite in plasma by high-performance liquid chromatography with ultraviolet and amperometric detection

This communication describes a rapid, sensitive and selective method for the assay of chlorprothixene and its sulfoxide metabolite in human plasma, using reversed-phase high-performance liquid chromatography. Alkalinized plasma was extracted with heptane--isoamyl alcohol (99:1), after addition of thioridazine as the internal standard. The residue obtained after evaporation of this extract was chromatographed on a cyano column, using acetonitrile--0.02 M potassium dihydrogen phosphate pH 4.5 (60:40) as the mobile phase with ultraviolet (229 nm) detection. Quantitation was based on peak height ratios over the concentration range of 5.0-50.0 ng/ml for both compounds with 85% and 90% recovery for chlorprothixene and its sulfoxide metabolite, respectively, using a 1.0-ml plasma sample. The assay chromatographically resolves chlorprothixene and the sulfoxide metabolite from the N-desmethyl metabolite, which can only be semi-quantitated owing to low and variable recoveries. The method was used to obtain plasma concentration versus time profiles in two subjects after oral administration of 100 mg of chlorprothixene suspension and in two additional subjects following overdosages of chlorprothixene estimated to exceed several hundred milligrams. These analyses demonstrated that the sulfoxide metabolite is the predominant plasma component following therapeutic administration and overdosages. High-performance liquid chromatography with oxidative amperometric detection with the glassy carbon electrode was also evaluated. Although this procedure demonstrated comparable sensitivity and precision to ultraviolet detection for the analysis of chlorprothixene and N-desmethyl chlorprothixene, the sulfoxide metabolite could not be measured with high sensitivity (less than 100 ng/ml) owing to endogenous interferences. Hence the utility of this alternative assay technique is limited.