نتایج جستجو برای: dissolution

تعداد نتایج: 20956  

2010
David J. Burdige Xinping Hu Richard C. Zimmerman DAVID J. BURDIGE XINPING HU

Using two complimentary approaches (pore water advection/diffusion/ reaction modeling and stable isotope mass balance calculations) we show that carbonate dissolution/reprecipitation occurs on early diagenetic time scales across a broad range of sediments on the Great Bahamas Bank. The input of oxygen into the sediments, which strongly controls sediment carbonate dissolution, has two major sour...

Journal: :International journal of pharmaceutics 2015
Min Xu Celine Valeria Liew Paul Wan Sia Heng

This study explored the application of 400-DS dissolution apparatus 7 for individual pellet dissolution methodology by a design of experiment approach and compared its capability with that of the USP dissolution apparatus 1 and 2 for differentiating the coat quality of sustained release pellets. Drug loaded pellets were prepared by extrusion-spheronization from powder blends comprising 50%, w/w...

2007
Jiwchar Ganor Peng Lu Chen Zhu

Weathering rates of silicate minerals observed in the laboratory are in general up to five orders of magnitude higher than those inferred from field studies. Simple calculations show that even if the field conditions were fully simulated in standard laboratory experiments, it would be impossible to measure the slow rates of mineral dissolution that are observed in the field. As it is not possib...

2000
C. M. Hassan J. H. Ward N. A. Peppas

A model was developed to describe the overall dissolution kinetics of semicrystalline PVA gels prepared by freezing and thawing techniques. The dissolution process was described as a three-step mechanism: detachment-, diffusion-, and disentanglement-controlled dissolution. The unfolding of crystalline regions due to detachment and diffusion was calculated. The lamellar thickness of a PVA crysta...

2014
Noelia L. Gonzalez Vidal Silvina G. Castro Sergio F. Sanchez Bruni Daniel A. Allemandi Santiago D. Palma

The rate-limiting step to drug absorption is often dissolution from the dosage form, especially for poorly soluble compounds. Two possibilities for improving the dissolution of these drugs are to increase the available surface area and to improve their apparent solubilities under physiologically relevant conditions with surfactants as wetting agents. Albendazole (ABZ), one of the most effective...

Journal: :European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences 2001
P Costa J M Sousa Lobo

Over recent years, drug release/dissolution from solid pharmaceutical dosage forms has been the subject of intense and profitable scientific developments. Whenever a new solid dosage form is developed or produced, it is necessary to ensure that drug dissolution occurs in an appropriate manner. The pharmaceutical industry and the registration authorities do focus, nowadays, on drug dissolution s...

2005
Masahiko Fujii Fei Chai

[1] Biogenic silica (bSiO2) dissolution plays an important role in the marine silicon cycle, diatom production and vertical export production. An ocean ecosystem model that incorporates dependency of bSiO2 dissolution on water temperature was used to examine the effects of bSiO2 dissolution on diatom production and bSiO2 export. Diatoms dominate with higher bSiO2 dissolution rates because of en...

2016
Xinping Hu David J. Burdige

Surface carbonate sediments from sites on the Bahamas Bank with different seagrass densities were incubated across a range of O2 delivery rates, to study the controls on metabolic carbonate dissolution in these sediments. The results confirmed the 1:1 ratio between the rates of O2 consumption and carbonate dissolution, demonstrating that microbial respiration was the ratelimiting step in metabo...

Journal: :Journal of controlled release : official journal of the Controlled Release Society 2008
Louise Ho Ronny Müller Keith C Gordon Peter Kleinebudde Michael Pepper Thomas Rades Yaochun Shen Philip F Taday J Axel Zeitler

The potential of terahertz pulsed imaging (TPI) to predict the dissolution performance in sustained-release tablets was investigated in this study. Batches of coated tablets with similar weight gain during the coating process at the lab and pilot scales were subjected to non-destructive imaging by TPI and subsequently analysed by dissolution testing. The results from the dissolution tests revea...

Journal: :Journal of pharmaceutical sciences 2014
Susumu Takeuchi Yasuhiro Tsume Gregory E Amidon Gordon L Amidon

In vitro dissolution tests are performed for new formulations to evaluate in vivo performance, which is affected by the change of gastrointestinal (GI) physiology, in the GI tract. Thus, those environmental changes should be introduced to an in vitro dissolution test. Many studies have successfully shown the improvement of in vitro-in vivo correlations (IVIVC) by introducing those physiological...

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