Physiology and pharmacology of the brushtail possum gastrointestinal tract: Relationship to the human gastrointestinal tract☆

McDowell, Arlene; McLeod, B. J.

doi:10.1016/j.addr.2007.06.012

Cited by 27 publications

(12 citation statements)

References 84 publications

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“…Therefore, numerous pH-sensitive polymeric micellar systems have been employed for intravenous administration of anticancer drugs to tumors [92–94]. In the GI tract, the pH varies from high acidity in the stomach (pH 1.0–2.5) to a neutral or slightly alkaline pH in the small intestine (pH 5.1–7.8) [95]. Such wide variation of pH along the GI tract has been utilized for controlled drug release from carriers [2].…”

Section: Pms For Enhancement Of Bioavailabilitymentioning

confidence: 99%

Polymeric Micelles, a Promising Drug Delivery System to Enhance Bioavailability of Poorly Water-Soluble Drugs

Ling

Tian-min

2013

Journal of Drug Delivery

466

209

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Oral administration is the most commonly used and readily accepted form of drug delivery; however, it is find that many drugs are difficult to attain enough bioavailability when administered via this route. Polymeric micelles (PMs) can overcome some limitations of the oral delivery acting as carriers able to enhance drug absorption, by providing (1) protection of the loaded drug from the harsh environment of the GI tract, (2) release of the drug in a controlled manner at target sites, (3) prolongation of the residence time in the gut by mucoadhesion, and (4) inhibition of efflux pumps to improve the drug accumulation. To explain the mechanisms for enhancement of oral bioavailability, we discussed the special stability of PMs, the controlled release properties of pH-sensitive PMs, the prolongation of residence time with mucoadhesive PMs, and the P-gp inhibitors commonly used in PMs, respectively. The primary purpose of this paper is to illustrate the potential of PMs for delivery of poorly water-soluble drugs with bioavailability being well maintained.

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Section: Pms For Enhancement Of Bioavailabilitymentioning

confidence: 99%

Polymeric Micelles, a Promising Drug Delivery System to Enhance Bioavailability of Poorly Water-Soluble Drugs

Ling

Tian-min

2013

Journal of Drug Delivery

466

209

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“…Although GI transit time can be varied by multiple factors [14], it is desirable that drug release from any oral drug formulation is completed within 12 h to avoid the drug loss and to maximize the bioavailability. The present study was also initiated from a hypothesis that the HP0 micelle possibly could not liberate all PTX within GI transit time (<12 h) due to the strong hydrotropic interaction.…”

Section: Resultsmentioning

confidence: 99%

“…In the GI tract, the pH varies from 1.0-2.5 in the stomach to 5.1-7.8 in the small intestine [13, 14]. Such wide variation of pH along the GI tract has been utilized for controlled drug release from carriers [15].…”

Section: Introductionmentioning

confidence: 99%

Hydrotropic polymer micelles containing acrylic acid moieties for oral delivery of paclitaxel

Kim

Huh

et al. 2008

Journal of Controlled Release

118

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Hydrotropic polymers (HPs) and their micelles have been recently developed as vehicles for delivery of poorly water-soluble drugs, such as paclitaxel (PTX), by oral administration. The release of PTX from HP micelles, however, was slow and it took more than a day for complete release of the loaded PTX. Since the gastrointestinal (GI) transit time is known to be only several hours, pH-sensitive HP micelles were prepared for fast release of the loaded PTX responding to pH changes along the GI tract. Acrylic acid (AA) was introduced, as a release modulator, into HPs by copolymerization with 4-(2-vinylbenzyloxy)-N,N-(diethylnicotinamide) (VBODENA). The AA content was varied from 0% to 50 % (in the molar ratio to VBODENA). HPs spontaneously produced micelles in water, and their critical micelle concentrations (CMCs) ranged from 31 μg/mL to 86 μg/mL. Fluorescence probe study using pyrene showed that blank HP micelles possessed a good pH-sensitivity, which was clearly observed at relatively high AA contents and pH > 6. The pH sensitivity also affected the PTX loading property. Above pH 5, the PTX loading content and loading efficiency in HP micelles were significantly reduced. Although this may be primarily due to the AA moieties, other factors may include PTX degradation and polymer aggregation. The PTX release from HP micelles with more than 20% (mol) AA contents was completed within 12 h in a simulated intestinal fluid (SIF, pH=6.5). The HP micelles without any AA moiety showed very slow release profiles. In the simulated gastric fluid (SGF, pH=1.6), severe degradation of the released PTX was observed. The pH-dependent release of PTX from HP micelles can be used to increase the bioavailability of PTX upon oral delivery.

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“…The first aims to identify toxins which are highly specific to marsupials, ideally brushtail possums. The intestinal physiology of the possum, especially the mechanisms responsible for fluid section across the gut wall, differs markedly from eutherian mammals (Butt et al 2002;McDowell & McLeod 2007). Consequently, disrupting the proteins responsible for fluid transport could lead to irreversible and uncontrolled fluid secretion resulting in diarrhoea, dehydration, hypovolemic shock and death.…”

Section: Secretory Toxins and Reproductive Controlsmentioning

confidence: 99%

A method for considering the acceptability of novel biotechnologies for the control of brushtail possums

Fisher¹

2010

Kotuitui: New Zealand Journal of Social Sciences Online

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Public acceptance and regulatory approval of biotechnologies is increasingly dependent on consideration of cultural, ethical and spiritual effects, and the opportunity for community involvement. The objective of this study was to articulate a means for researchers to identify relevant issues during the development of the technologies. It encompassed the substantive issues, such as safety, the provision of credible and adequate public information, and the opportunity for citizens, as well as stakeholders, to give society's informed consent. In this initial analysis of novel toxins and infertility or sterility-inducing agents being developed to manage pest populations of brushtail possums, several issues were identified. They included the risk associated with fertility controls entering the food chain, the severity of animal welfare compromise with toxins, and the adequacy of terminology used to describe pest control agents. This approach provides a means for researchers to acknowledge the issues contributing to public acceptance of biotechnologies during their development and with the involvement of those with interests in biotechnology.

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Physiology and pharmacology of the brushtail possum gastrointestinal tract: Relationship to the human gastrointestinal tract☆

Cited by 27 publications

References 84 publications

Polymeric Micelles, a Promising Drug Delivery System to Enhance Bioavailability of Poorly Water-Soluble Drugs

Polymeric Micelles, a Promising Drug Delivery System to Enhance Bioavailability of Poorly Water-Soluble Drugs

Hydrotropic polymer micelles containing acrylic acid moieties for oral delivery of paclitaxel

A method for considering the acceptability of novel biotechnologies for the control of brushtail possums

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