Gastrointestinal transit in the common brushtail possum measured by gamma scintigraphy

This paper reports an example of the application of pharmaceutical technology to wildlife management, specifically the design of an oral delivery system for the common brushtail possum in New Zealand. Designing an oral delivery system requires a knowledge of the time taken for particulates to reach target sites within the gastrointestinal tract (GIT). The transit time for fluid and indigestible particles of two different size ranges was determined in the common brushtail possum (Trichosurus vulpecula). Technetium-labelled (Tc-99m) anion exchange resin particles (75-125 or 500-700 mu m diameter) or solution (Tc-99m-labelled diethylenetriamine pentaacetic acid, Tc-99m-DTPA) was administered orally. At predetermined times after dosing (3, 6, 12, 24 or 32 h), the distribution of radioactivity throughout excised gastrointestinal tracts was determined by gamma scintigraphy. The transit profile was similar for the three formulations investigated. Unlike other closely related hindgut fermenting marsupials, there was no evidence to support the presence of a colonic separating mechanism in the common brushtail possum. Gastrointestinal transit was independent of body mass, gender and time of day that the dose is given. To target the hindgut for oral delivery of protein and peptide biocontrol agents, the formulation Would need to protect the bioactive for approximately 12 h prior to release. (c) 2005 Elsevier B.V. All rights reserved.

Physical enhancement of transdermal drug application: is delivery technology keeping up with pharmaceutical development?

Advances in molecular biology have given us a wide range of protein and peptide-based drugs that are unsuitable for oral delivery because of their high degree of first-pass metabolism. Though parenteral delivery is the obvious answer, for the successful development of commercial chronic and self-administration usage formulations it is not the ideal choice. Transdermal delivery is emerging as the biggest application target for these agents, however, the skin is extremely efficient at keeping out such large molecular weight compounds and therapeutic levels are never going to be realistically achieved by passive absorption. Physical enhancement mechanisms including: iontophoresis, electroporation, ultrasound, photomechanical waves, microneedles and jet-propelled particles are emerging as solutions to this topical delivery dilemma. Adding proteins and peptides to the list of other large molecular weight drugs with insufficient passive transdermal fluxes to be therapeutically useful, we have a collection of pharmacological agents waiting for efficient delivery methods to be introduced. This article reviews the current state of physical transdermal delivery technology, assesses the pros and cons of each technique and summarises the evidence-base of their drug delivery capabilities.

Adopting turtle excluder devices in Australia and the United States: What are the differences in technology transfer, promotion, and acceptance?

Turtle excluder devices (TEDs) are being trialed on a voluntary basis in many Australian prawn (shrimp) trawl fisheries to reduce sea turtle captures. Analysis of TED introductions into shrimp trawl fisheries of the United States provided major insights into why conflicts occurred between shrimpers, conservationists, and government agencies. A conflict over the introduction and subsequent regulation of TEDs occurred because the problem and the solution were perceived differently by the various stakeholders. Attempts to negotiate and mediate the conflict broke down, resulting in litigation against the U.S. government by conservationists and shrimpers. Litigation was not an efficient resolution to the sea turtle-TED-trawl conflict but it appears that litigation was the only remaining path of resolution once the issue became polarized. We review two major Australian trawl fisheries to identify any significant differences in circumstances that may affect TED acceptance. Australian trawl fisheries are structured differently and good communication occurs between industry and researchers. TEDs are being introduced as mature technology. Furthermore, bycatch issues are of increasing concern to all stakeholders. These factors, combined with insights derived from previous conflicts concerning TEDs in the United Stares, increase the possibilities that TEDs will be introduced to Australian fishers with better acceptance.

Effect of metabolic inhibitors on cyclosporine pharmacokinetics using a population approach

Drugs known to inhibit the metabolism of cyclosporine are administered concomitantly to those who undergo cardiothoracic transplantation. The aim of this study was to examine in quantitative terms the relationship between cyclosporine oral dose rate and the trough concentration (Css(trough)) at steady state in patients who undergo cardiothoracic transplantation and are administered cyclosporine alone or in combination with drugs known to inhibit its metabolism. Dose and whole blood cyclosporine Css(tough) observations measured using the enzyme-multiplied immunoassay technique (EMIT) (396 observations) or the TDx assay (435 observations) were collected as part of routine blood concentration monitoring from 182 patients who underwent cardiothoracic transplantation. Data were analyzed using a linear mixed-effects modeling approach to examine the effect of metabolic inhibitors on dose-rate-Css(trough) ratio. The mean (and 95% confidence interval) dose-rate-Css(trough) ratio for cyclosporine generated from concentrations measured using EMIT was 94 (82.5-105.5) Lh(-1) for patients administered cyclosporine alone, 66.7 (58.1-75.3) Lh(-1) for patients administered concomitant diltiazem, 47.9 (15.4 -80.4) Lh(-1) for patients administered concomitant itraconazole, 21.7 (14.8-28.5) Lh(-1) for patients administered concomitant ketoconazole, and 14.9 (11.8-18.1) Lh(-1) for patients concomitantly administered diltiazem and ketoconazole. For patients administered concomitant cyclosporine, ketoconazole, and diltiazem, the dosage of cyclosporine, if it is administered alone, should be 20% to achieve the same blood concentrations. This will allow safer drug concentration targeting of cyclosporine after cardiothoracic transplantation.

The knowledge gap: A perspective on trade, industry, technology and policy from pre-war Australian music technology manufacturing (1903-30)

Australia struggles to achieve economic competitiveness, prevent expansion of the trade deficit and develop value-added production despite applications of policy strategies from protectionism to trade liberalisation. This article argues that these problems were emerging at the turn of the century, and that an investigation of music technology manufacturing in the first two decades of this century reveals fundamental problems in the conduct of relevant policy analysis. Analysis has focused on the trade or technology gap which is only symptomatic of an underlying knowledge gap. The article calls for a knowledge policy approach which can allow protection without the negative effects of isolation from global markets and without having to resort to unworkable utopian free-trade dogma. A shift of focus from a 'goods traded' view to a knowledge transaction (or diffusion) perspective is advocated.

Accessibility to general practitioners in rural South Australia - A case study using geographic information system technology

Objective: To demonstrate the potential of GIS (geographic information system) technology and ARIA (Accessibility/Remoteness Index for Australia) as tools for medical workforce and health service planning in Australia. Design: ARIA is an index of remoteness derived by measuring road distance between populated localities and service centres. A continuous variable of remoteness from 0 to 12 is generated for any location in Australia. We created a GIS, with data on location of general practitioner services in non-metropolitan South Australia derived from the database of HUMPS (Rural Undergraduate Medical Placement System), and estimated, for the 1170 populated localities in South Australia, the accessibility/inaccessibility of the 109 identified GP services. Main outcome measures: Distance from populated locality to GP services. Results: Distance from populated locality to GP service ranged from 0 to 677 km (mean, 58 km). In all, 513 localities (43%) had a GP service within 20 km (for the majority this meant located within the town). However, for 173 populated localities (15%), the nearest GP service was more than 80 km away. There was a strong correlation between distance to GP service and ARIA value for each locality (0.69; P<0.05). Conclusions: GP services are relatively inaccessible to many rural South Australian communities. There is potential for GIS and for ARIA to contribute to rational medical workforce and health service planning. Adding measures of health need and more detailed data on types and extent of GP services provided will allow more sophisticated planning.