Lipid, sugar and liposaccharide based delivery systems 2

The vast majority of biologically active compounds will never be considered as potential drugs due to inherently poor bioavailability. This review discusses the progress in the development of chemical systems to improve the metabolic stability, absorption and physicochemical properties of potential drugs. Delivery systems that involve the conjugation of lipid and/or sugar moieties are highlighted, as well as novel methods of conjugation of these groups to drugs. The use of sugar molecules to target drugs to particular organs or cells is also discussed, as is the use of lipids in the growing area of gene delivery. This is an update of a previous review [1].

The promotion and disruption of community service delivery systems

In this paper, we report data drawn from a larger project on the functioning of the Queensland community service delivery system, particularly that providing services to people with disabilities. Our reasoning for focusing at this level is that, from the service user's perspective, support is derived from the service delivery system, not just individual service providers. Defining the service delivery system as formal services and informal support networks, we undertook interviews and focus groups with service providers in six areas in Queensland: inner urban, outer urban, rural and remote. The period on which we report is one in which considerable reform activity had been undertaken by funding bodies of the Commonwealth and State governments. We report on those factors we identified which promote the integrated functioning of the service delivery system, as well as those factors that disrupt it. We conclude with a brief evaluative analysis of the current status of the system.

Layered double hydroxide nanomaterials as potential cellular drug delivery agents

This paper briefly reviews the recent progress in using layered double hydroxide (LDH) nanomaterials as cellular delivery agents. The advantages of LDHs as cellular delivery agents are summarized, and the processes of interaction/de-intercalation of anionic drugs (genes) into/from LDH nanoparticles are discussed. Then the cellular delivery of LDH-drug (gene) nanohybrids and subsequent intracellular processes are presumably proposed. At the end, some challenges and remarks for efficient delivery of drugs (genes) via LDH nanoparticles are provided to the best of our knowledge.

Gas and particle dynamics of a contoured shock tube for pre-clinical microparticle drug delivery

We investigate the gas-particle dynamics of a device designed for biological pre-clinical experiments. The device uses transonic/supersonic gas flow to accelerate microparticles such that they penetrate the outer skin layers. By using a shock tube coupled to a correctly expanded nozzle, a quasi-one-dimensional, quasi-steady flow (QSF) is produced to uniformly accelerate the microparticles. The system utilises a microparticle cassette (a diaphragm sealed container) that incorporates a jet mixing mechanism to stir the particles prior to diaphragm rupture. Pressure measurements reveal that a QSF exit period - suitable for uniformly accelerating microparticles - exists between 155 and 220 mus after diaphragm rupture. Immediately preceding the QSF period, a starting process secondary shock was shown to form with its (x,t) trajectory comparing well to theoretical estimates. To characterise the microparticle, flow particle image velocimetry experiments were conducted at the nozzle exit, using particle payloads with varying diameter (2.7-48 mu m), density (600-16,800 kg/m(3)) and mass (0.25-10 mg). The resultant microparticle velocities were temporally uniform. The experiments also show that the starting process does not significantly influence the microparticle nozzle exit velocities. The velocity distribution across the nozzle exit was also uniform for the majority of microparticle types tested. For payload masses typically used in pre-clinical drug and vaccine applications (

Transdermal drug delivery: Basic principles for the veterinarian

The use of topical pharmaceutical formulations is increasingly popular in veterinary medicine. A potential concern is that not all formulations are registered for the intended species, yet current knowledge strongly suggests that simple extrapolation of transdermal drug pharmacokinetics and pharmacodynamics between species, including humans, cannot be done. In this review, an overview is provided of the underlying basic principles determining the movement of topically applied molecules into and through the skin. Various factors that may affect transdermal drug penetration between species, between individuals of a particular species and regional differences in an individual are also discussed. A good understanding of the basic principles of transdermal drug delivery is critical to avoid adverse effects or lack of efficacy when applying topical formulations in veterinary medicine. (c) 2005 Elsevier Ltd. All rights reserved.