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Gelling Agent (gelling + agent)
Selected AbstractsSustained ophthalmic in situ gel of ketorolac tromethamine: rheology and in vivo studiesDRUG DEVELOPMENT RESEARCH, Issue 6 2009A.S. Manjappa Abstract Most ocular diseases are treated with topical eye drops. The poor bioavailability and therapeutic response exhibited by these conventional eye drops due to rapid precorneal elimination of the drug may be overcome by the use of in situ gelling systems that are instilled as drops into the eye and undergo a sol-to-gel transition in the cul-de-sac. The present work describes the formulation and evaluation of an ophthalmic delivery system of the nonsteroidal anti-inflammatory drug (NSAID), ketorolac tromethamine, based on the concept of pH-triggered in situ gelation. Polyacrylic acid (Carbopol® 934) was used as the gelling agent in combination with hydroxypropylmethylcellulose (Methocel E15LV), which acted as a viscosity enhancer. The prepared formulations were characterized for clarity, pH, drug content, rheology, and in vivo drug release. Clarity, pH, and drug content of the developed formulations were found to be satisfactory. The developed formulation showed pseudo-plastic rheology. The formulation with benzalkonium chloride and edetate disodium improved the rate of corneal absorption but not the extent. The developed formulation is a viable alternative to conventional eye drops by virtue of its ability to enhance bioavailability through its longer precorneal residence time and ability to sustain drug release. Also importantly is the ease of instillation afforded and decreased frequency of instillation resulting in better patient acceptance. Drug Dev Res, 2009. © 2009 Wiley-Liss, Inc. [source] Behenamidopropyl Dimethylamine: unique behaviour in solution and in hair care formulationsINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 4 2010M. Minguet Synopsis The rise of ecological awareness among consumers and industry has impacted the cationic surfactants market. The most used cationic surfactants present some drawbacks in this sense. Therefore, new molecules are being studied and developed which fulfil eco-toxicological requirements without losing performance. One of these surfactants is Behenamidopropyl Dimethylamine (BAPDMA). This biodegradable amidoamine, which converts into a cationic surfactant at acidic pH, shows outstanding water solubility, despite its very long alkyl chain. Its behaviour in solution has been exhaustively studied. The conditioning performance of this product is superior to that of commonly used cationic surfactants, providing a superior sensorial profile and improved combing force reductions on hair. Moreover, other applications for this product in the non-ionic form have been studied, such as conditioning agent in 2 in 1 shampoos, where it also shows colour protection effects, and as gelling agent in hair colouration creams. This multifunctional and high performance profile, together with an improved biodegradation and aquatic toxicity compared with currently used cationic surfactants, make this product a very interesting eco-friendly alternative for the hair care market. Résumé L'essor de la conscience écologique parmi les consommateurs et l'industrie a eu un fort impact dans le marché des tensioactifs cationiques. Les plus employés d'entre eux ont quelques désavantages de ce point de vue. À ce sujet, on est en train d'étudier et développer des nouvelles molécules qui accomplissent les conditions éco-toxicologiques, sans perdre leur efficacité adoucissante. Un de ces tensioactifs c'est la Behenamidopropyl Dimethylamine (BAPDMA). Cette amidoamine, qui est totalement biodégradable et non toxique pour l'environnement, évolue dans un tensioactif cationique à des pHs acides. Dans l'eau le produit montre une solubilité inespérément élevée, malgré qu'il a une chaîne alchilyque très longue. On a étudiéà fond son comportement en dissolution. L'efficacité de conditionnement du produit se montre supérieure à celle des tensioactifs cationiques employés habituellement, en donnant un profil sensoriel supérieur et en améliorant la souplesse de coiffure. En plus, pour ce produit, d'autres applications ont étéétudiées dans la forme non ionique, par exemple, son emploi comme agent conditionneur dans des shampooings 2 en 1, où il montre aussi un effet protecteur de la couleur et comme agent de texture dans des crèmes de coloration capillaire. Ce profil multifonctionnel et de haute efficacité, ainsi que un bon profil éco-toxicologique, en comparaison avec les tensioactifs cationiques employés actuellement, fait que la behenamidopropyl dimethylamine soit une très bonne alternative pour le marché du soin capillaire. [source] CHARACTERISTICS OF GELLAN GUM BASED FOOD GELSJOURNAL OF TEXTURE STUDIES, Issue 4 2010DIPJYOTI SAHA ABSTRACT Fruit-based gels with gellan gum as the gelling agent was prepared. Textural attributes of the gellan gum gels, formed with different concentrations of the gum (0.5,3.0%) and sugar and/or pineapple juice, were determined employing the methods of large-deformation uniaxial compression and stress relaxation. Fracture stress/energy markedly increases with an increase in the concentration of gellan gum while fracture strain exhibits a marginal effect. The change in these compressive textural parameters is more pronounced for sugar added samples compared with gels without sugar. Marked decay in stress relaxation curves was observed; the extent of relaxation decreases marginally with an increase in gum content up to 2% but shows much lesser values beyond 2% addition. The sugar added samples exhibit lesser relaxation characteristics but higher relaxation times indicating elastic characteristics compared with samples without sugar. Use of gellan gum provides an innovative method for developing fruit juice based gels as a convenience food because of attractive transparent appearance and textural attributes. PRACTICAL APPLICATION The use of hydrocolloids like gellan gum can develop fabricated foods in the form of fruit juice based gels having unique textural properties. These properties can be altered to suit the consumer preference by varying the proportions of gellan gum, fruit juice and sugar. The results in the present investigation arising from compression and relaxation testing thus help in characterizing the developed gels. [source] Factors affecting adventitious regeneration from in vitro leaf explants of ,Improved French' plum, the most important dried plum cultivar in the USAANNALS OF APPLIED BIOLOGY, Issue 1 2010C. Petri An adventitious shoot regeneration protocol from in vitro leaves of the most important dried plum cultivar in the USA, ,Improved French', has been established. Factors affecting regeneration were studied in order to optimise regeneration. The proliferation medium in which the shoots, used as the source of leaf explants, were cultured had a strong influence on subsequent regeneration. Shoot regeneration was observed at a mean frequency of 52% when a Murashige-based and Skoog-based shoot culture medium with 3 ,M N6 -benzylaminopurine and 0.25 ,M indole-3-butyric acid (IBA) was employed compared with shoot regeneration frequencies of less than 5% for a Quoirin-based and Lepoivre-based shoot culture medium, with 8.9 ,M N6 -benzylaminopurine and 0.49 ,M IBA. The shoot regeneration medium contained ,-naphthaleneacetic acid at 2.0,6.0 ,M and thidiazuron at 4.5,15.0 ,M. 2,4 Dichlorophenoxy-acetic acid at 9.0 ,M was included in the medium but only for the first 4 days of culture. Shoot regeneration frequencies were positively related to thidiazuron concentration and significantly greater (P < 0.05) for 9,15 ,M thidiazuron than for the media with 4.5 ,M thidiazuron. Leaf explants, incubated in a 16-h-light/8-h-dark photoperiod or in the dark for 1 week followed by exposure to light, showed significantly more organogenic activity (P < 0.01) than was observed for leaves cultured in the dark for 2 or 3 weeks before they were transferred to the light. The utilisation of Bacto agar (0.7%) as the gelling agent increased organogenesis compared with media gelled with TC Agar (0.7%), or an agar,gellan gum blend (AgargelÔ) (0.45%). The addition of the ethylene inhibitor silver thiosulphate at 60,120 ,M also improved organogenesis. When all the studied factors were optimised, a regeneration rate of 65% was achieved. Rooting frequency of regenerated shoots was significantly increased (P < 0.05) by the use of full-strength Murashige and Skoog salts (40%) or 100 mg L,1 phloroglucinol (53%) to the rooting medium. [source] Cloning, expression, purification, crystallization and preliminary crystallographic studies of UgdG, an UDP-glucose dehydrogenase from Sphingomonas elodea ATCC 31461ACTA CRYSTALLOGRAPHICA SECTION F (ELECTRONIC), Issue 1 2010Joana Rocha Gellan gum, a commercial gelling agent produced by Sphingomonas elodea ATCC 31461, is a high-value microbial exopolysaccharide. UDP-glucose dehydrogenase (UGD; EC 1.1.1.22) is responsible for the NAD-dependent twofold oxidation of UDP-glucose to UDP-glucuronic acid, one of the key components for gellan biosynthesis. S. elodea ATCC 31461 UGD, termed UgdG, was cloned, expressed, purified and crystallized in native and SeMet-derivatized forms in hexagonal and tetragonal space groups, respectively; the crystals diffracted X-rays to 2.40 and 3.40,Å resolution, respectively. Experimental phases were obtained for the tetragonal SeMet-derivatized crystal form by a single-wavelength anomalous dispersion experiment. This structure was successfully used as a molecular-replacement probe for the hexagonal crystal form of the native protein. [source] Influence of magnesium aluminium silicate on rheological, release and permeation characteristics of diclofenac sodium aqueous gels in-vitroJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 4 2005Thaned Pongjanyakul The effect of magnesium aluminium silicate (MAS) on rheological, release and permeation characteristics of diclofenac sodium (DS) aqueous gels was investigated. DS aqueous gels were prepared using various gelling agents, such as 15% w/w poloxamer 407 (PM407), 1% w/w hydroxypropylmethylcellulose (HPMC), and 1% w/w high and low viscosity grades of sodium alginate (HV-SA and LV-SA, respectively). Different amounts of MAS (0.5, 1.0 and 1.5% w/w) were incorporated into the DS gels. Incorporation of MAS into the DS gels prepared using SA or PM407 caused a statistical increase in viscosity (P<0.05) and a shift from Newtonian flow to pseudoplastic flow with thixotropic property. The DS release rates of these composite gels were significantly decreased (P<0.05) when compared with the control gels. This was due to an interaction between MAS and PM407 or SA, and adsorption of DS onto MAS particles. Moreover, a longer lag time and no change in DS permeation flux were found when MAS was added to the gels. The findings suggest that the rheological characteristics of gels prepared using PM407 or SA could be improved by incorporating MAS. However, the use of MAS could retard the DS release and extend the lag time of DS permeation. [source] | |||||||||||||