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Various Formulations (various + formulations)
Selected AbstractsLyophilised liposome-based formulations of ,-tocopheryl succinate: Preparation and physico-chemical characterisationJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 5 2010pán Koudelka Abstract ,-Tocopheryl succinate (,-TOS) is a semisynthetic analogue of ,-tocopherol with selective toxicity to the cancer cells and anticancer activity in vivo. Yet, no suitable formulation of ,-TOS for medical application has been reported. Various formulations, for example, solutions in organic solvents, oil emulsions and vesicules prepared by spontaneous vesiculation, polyethylene glycol conjugates and liposomes of various compositions have been tested. We developed and characterised a stable lyophilised liposome-based ,-TOS formulation. ,-TOS (15,mol%) was incorporated into large oligolamellar vesicles (OLVs) composed of soy phosphatidylcholine (SPC) by the method of lipid film hydration followed by extrusion through polycarbonate filters. Stabilised liposomal formulation was prepared by lyophilisation in the presence of sucrose (molar ratio lipid/sucrose, 1:5). The size distribution of the liposomes (130,140,nm, polydispersity index 0.14) as well as the stable lipid and ,-TOS contents were preserved during storage in the lyophilised form at 2,8°C for at least 6 months. The data indicate good physical and chemical stability of the lyophilised preparation of ,-TOS liposomes that can be used in clinical medicine. © 2009 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 99: 2434,2443, 2010 [source] Preparation of oily core polyamide microcapsules via interfacial polycondensation,POLYMER INTERNATIONAL, Issue 4 2003L Soto-Portas Abstract Microcapsules obtained by interfacial polycondensation from an original system based on the polyaddition of specific di- or polyamines and more classical acyl chloride molecules were studied. The originality of the system lies in the fact that the encapsulated agent is the internal phase allowing its incorporation without an organic solvent, which is an advantage from the point of view of environmental protection. Once the optimal parameters of the emulsion were determined, the membrane formation was studied by optimizing the emulsification and reaction times in relation to simultaneous acyl chloride hydrolysis. The microcapsules were obtained by interfacial polycondensation between an excess of amine functions (diamine and diethylenetriamine) and acyl chloride (sebacoyl chloride and 1,3,5-benzene tricarbonyl trichloride) from an oil-in-water emulsion in the presence of 88% hydrolyzed poly(vinyl alcohol) as a surfactant. Various formulations in terms of COCl concentration, crosslinking agent concentration, excess of amine functions, emulsification and reaction times were prepared. The hydrolysis of acyl halide functions is the main parameter which influences the growth of the membrane. The increase in acyl chloride function concentration allows compensation for that lost by hydrolysis, and increases the encapsulation yield to about 90%. The degree of crosslinking of the membrane was controlled in order to minimize the subsequent release of oil by the addition of trifunctional monomers. An optimal formulation was developed offering high encapsulation yield and optimal elastic behaviour. Almost spherical capsules, with a membrane thickness of approximately 500,nm, relatively smooth internal walls and crumpled external walls, were observed by scanning electron microscopy. © 2003 Society of Chemical Industry [source] Formulation and evaluation of chitosan microspheres of aceclofenac for colon-targeted drug deliveryBIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 7 2010S. K. Umadevi Abstract The objective of this investigation was to develop novel colon specific drug delivery. Aceclofenac, a NSAID, was successfully encapsulated into chitosan microspheres. Various formulations were prepared by varying the ratio of chitosan, span-85 and stirring speed and the amount of glutaraldehyde. The SEM study showed that microspheres have smooth surfaces. Microspheres were characterised by Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC) to confirm the absence of chemical interactions between drug and polymer and to know the formation of microspheres structure. The microspheres were evaluated for particle size, encapsulation efficiency, drug loading capacity, mucoadhesion studies, stability studies, in vitro and in vivo drug release studies. Particle sizes, as measured by the laser light scattering technique, were of an average size in the range 41,80,µm. The swelling index was in the range 0.37,0.82 and the entrapment efficiency range was 51,75% for all the formulations. The optimised batch ACM13 released 83.6% at 8,h and 104% at 24,h in SCF containing rat caecal content. Eudragit coated chitosan microspheres prevented the release of the aceclofenac in the physiological environment of the stomach and small intestine and released 95.9±0.34% in the colon. With regard to release kinetics, the data were best fitted with the Higuchi model and showed zero order release with non-Fickian diffusion mechanism. The in vivo findings suggest that aceclofenac microspheres exhibit a prolonged effect of aceclofenac in rats and produce a significant anti-inflammatory effect. The findings of the present study conclusively state that chitosan microspheres are promising for colon targeting of aceclofenac to synchronise with chronobiological symptoms of rheumatoid arthritis. Copyright © 2010 John Wiley & Sons, Ltd. [source] Pharmacokinetics and protein binding of the selective neuronal nitric oxide synthase inhibitor 7-nitroindazoleBIOPHARMACEUTICS AND DRUG DISPOSITION, Issue 6 2000Mark A. Bush Abstract Utilization of nitric oxide (NO) synthase (NOS) inhibitors to probe the role of NO in various central nervous system processes requires use of an inhibitor selective for neuronal NOS, and is facilitated by knowledge of the pharmacokinetics of the inhibitor. The present project was undertaken to elucidate the disposition of the selective neuronal NOS inhibitor 7-nitroindazole (7-NI). A simple, specific HPLC assay was developed with requisite sensitivity to quantitate 7-NI in serum after administration of pharmacologically relevant doses. Further experiments were performed to assess the effects of administered dose on 7-NI disposition. 7-NI displayed marked nonlinearity, consistent with saturable elimination, when administered by ip injection in peanut oil. The nonlinearity was related to total dose, but not to the concentration of 7-NI in the vehicle. Binding of 7-NI in rat serum was concentration-independent and does not contribute to the nonlinearity. Various formulations for iv administration of this water-insoluble compound were evaluated; the optimal vehicle, from the standpoint of 7-NI solubility, appeared to inhibit the clearance of 7-NI from the systemic circulation. Considering the nonlinear disposition of 7-NI, knowledge of the pharmacokinetics of this inhibitor is requisite to designing administration protocols to achieve the desired magnitude and duration of NOS inhibition. Copyright © 2000 John Wiley & Sons, Ltd. [source] Paying attention to attention: New economies for learningEDUCATIONAL THEORY, Issue 4 2004Suzanne De Castell Challenging formal education's traditional monopoly over the mass-scale acculturation of youth, the technological infrastructure of the new economy brings in its wake a new "attentional economy" in which any "connected" adult or child owns and controls a full economic share of her or his own attention. For youth who have never known the text-bound world from which their elders have come, new technologies afford them far greater power and greatly expanded rights that enable them to decide for themselves what they can see, think, and do, as their teachers grapple with ways to attract, rather than compel, students' voluntary attention. This paper reviews various formulations of "attentional economy," and it urges the study of popular forms of technologically enabled play. These technologies effectively mobilize, direct, and sustain the engaged attention of youth, whose learning in and through play far exceeds the kind of glazed-eyed button-mashing complained of by those who have made little effort to understand the educative prospects of computer gaming. [source] Using translational medicine to understand clinical differences between botulinum toxin formulationsEUROPEAN JOURNAL OF NEUROLOGY, Issue 2006K. R. Aoki When using botulinum toxin-based products, the physician must decide the optimal location and dose required to alleviate symptoms and improve the patient's quality of life. To deliver effective treatment, the physician needs to understand the importance of accurate target muscle selection and localization and the implications of each product's migration properties when diluted in different volumes. Pre-clinical mouse models of efficacy and safety have been utilized to compare local and distal muscle relaxation effects following defined intramuscular administration. Data from the model allow the products to be ranked based on their propensity for local efficacy versus their distal migration properties. Using standardized dilutions, the non-parallel dose,response curves for the various formulations demonstrate that they have different efficacy profiles. Distal effects were also noted at different treatment doses, which are reflected in the different safety and/or therapeutic margins. Based on these pre-clinical data, the safety and therapeutic margin rankings are ordered, largest to smallest, as BOTOX®, Dysport® and Myobloc®. The results of subsequent clinical trials are variable and dose comparisons are inconclusive, thus supporting the regulatory position that the dose units of the individual preparations are unique and cannot be simply converted between products. [source] BRIEF COMMUNICATIONS: A quantity survey of intravenous administration of metronidazole in its different forms in a tertiary teaching hospitalINTERNAL MEDICINE JOURNAL, Issue 8 2010L. L. Lee Abstract The aim of this paper is to examine the prescribing patterns and cost of various formulations of metronidazole in a hospital setting over a 3-month period. Oral metronidazole has high bioavailability (98.9%) with peak plasma concentrations averaged at 2.3 h after dosing. Despite the high bioavailability of oral metronidazole, many patients continue to receive metronidazole intravenously when they are suitable for oral preparation. An audit of 120 consecutive patients prescribed metronidazole was conducted at the Liverpool Hospital, NSW, from March to July 2005. There were 65 men and 55 women (age 18,93). Of the 120 patients, 16 were on oral, 1 on rectal and 103 were on intravenous metronidazole. Treatment was initiated based on clinical diagnoses. Potential pathogens were subsequently identified on only 21 occasions. The use of metronidazole as an oral preparation was contraindicated in 27 patients (22.5%) who were nil-by-mouth. Of these, rectally administered metronidazole was contraindicated in only eight patients. The average course of intravenous metronidazole was 8.0 ± 9.7 days (mean ± SD). The total number of intravenous metronidazole treatment days was 824. Oral metronidazole would have been possible in 618 out of the 824 days. The estimated cost to administer each dose of oral, suppository and intravenous forms of metronidazole is $A0.11, $A1.34 and $A6.09 respectively. Thus, substantial savings could be achieved if oral metronidazole were to be administered whenever possible. The early use of oral or rectal metronidazole should be encouraged when there are no clinical contraindications. [source] On discontinuous Galerkin methodsINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 8 2003O. C. Zienkiewicz Abstract Discontinuous Galerkin methods have received considerable attention in recent years for problems in which advection and diffusion terms are present. Several alternatives for treating the diffusion and advective fluxes have been introduced. This report summarizes some of the methods that have been proposed. Several numerical examples are included in the paper. These present discontinuous Galerkin solutions of one-dimensional problems with a scalar variable. Results are presented for diffusion,reaction problems and advection,diffusion problems. We discuss the performance of various formulations with respect to accuracy as well as stability of the method. Copyright © 2003 John Wiley & Sons, Ltd. [source] Transdermal delivery of two antioxidants from different cosmetic formulationsINTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 1-2 2003S. Richert Synopsis The efficacy of any cosmetic product containing a functional ingredient is determined by the skin delivery of the active molecule, which is influenced by the type of the vehicle and the molecule itself. This study was designed to compare the percutaneous absorption habits of the antioxidants carcinine and lipoic acid out of various formulations by means of the porcine skin model. Initial evaluation of the in vitro porcine skin model has demonstrated its feasibility for various substances and formulations [1, 2]. Increasing legal requirements for risk assessment in the cosmetic industry have led to the development of this alternative test method. The penetration properties are determined by the OECD Guideline TG 428: Skin Absorption: in vitro Method [3, 4], which allows the use of porcine skin for penetration studies. Porcine skin is used because of its similarity to human skin in terms of its morphology and the essential permeation characteristics [5]. The mass balances for each tested formulation type of the antioxidants show individual penetration behaviours with significant differences. The presented data plainly demonstrate that the lipophilic lipoic acid has a distinct higher penetration potential than the hydrophilic carcinine. The chosen vehicle can enhance or reduce the transdermal delivery of both tested antioxidants. Modern effective cosmetic formulations will work only, if the active ingredients penetrate into the epidermis. In conclusion, the correct selection of a suitable formulation plays an important role during product development. Résumé L'efficacité d'un produit cosmétique ou de son principe actif est définie par l'absorption du principe actif par la peau. Cette action est influencée par la structure moléculaire du principe actif ainsi que par la galénique du produit. Dans cette étude, les taux d'absorption percutanée des agents anti-oxydants Carcinine et Acide Lipoïque intégrés dans différentes formulations cosmétiques ont été comparés avec le modèle de peau porcine. La phase de validation sur plusieurs années du modèle peau porcine in vitro a prouvé qu'il se prête très bien à la détermination de la pénétration percutanée de différentes substances et formulations. Des exigences légales de plus en plus sévères concernant la pratique des tests de sécurité pour les produits cosmétiques ont mené au développement de cette méthode qui remplace les essais sur animaux. La définition des qualités de pénétration se fait selon la directive OECD TG 428 : Skin Absorption : in vitro Method [3, 4] qui permet l'utilisation de la peau porcine provenant des abattoirs pour l'exécution des études de pénétration. Les bilans quantitatifs des formulations testées montrent que les agents anti-oxydants ont des comportements de pénétration différant de manière significative. Les données présentées démontrent très clairement que l'acide Lipoïque, lipophile, possède un potentiel de pénétration bien plus élevé que la Carcinine, hydrophile. La base cosmétique peut aussi réduire ou augmenter le potentiel de pénétration des agents anti-oxydant testés. En résumé, le choix correct d'un type de formulation joue un rôle très important dans le développement d'un produit cosmétique. [source] Formulation and food effects on the oral absorption of a poorly water soluble, highly permeable antiretroviral agentJOURNAL OF PHARMACEUTICAL SCIENCES, Issue 6 2002Bruce J. Aungst Abstract DPC 961 is a low-solubility, high-permeability, second-generation non-nucleoside reverse transcriptase inhibitor. The purpose of these studies was to evaluate the effects of drug substance and formulation variables on DPC 961 oral absorption, and to compare fed and fasted state oral absorption. To accomplish this, groups of four to six dogs were dosed with various formulations of DPC 961 under fasted or fed conditions, and DPC 961 pharmacokinetics were examined. Absolute oral bioavailability, based on i.v. AUC in the same dogs, was 24% after a suspension dose in fasted dogs and was 51% in fed dogs. Bioavailability with an unoptimized tablet formulation was 30% in fasted dogs and 86% in fed dogs. DPC 961 oral absorption was shown to be dependent on drug substance particle size in fasted dogs, after dosing with a tablet formulation where only the drug substance particle size was varied, but there was no difference in fed dogs. AUC and Cmax increased in proportion with increases in tablet strength from 100 to 400 mg, using tablets manufactured from a common granulation. Tablets made with 50 and 66% drug loadings showed similar relative oral bioavailabilities. Tablets prepared with two different polymorphic forms of DPC 961 were also compared, and these were found to be equivalent. These studies provided a useful component of the formulation development process, to help identify and control the variables affecting oral absorption of this potential new therapeutic agent. © 2002 Wiley-Liss, Inc. and the American Pharmaceutical Association J Pharm Sci 91:1390,1395, 2002 [source] Chitosan nanoparticles encapsulated vesicular systems for oral immunization: preparation, in-vitro and in-vivo characterizationJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 3 2006Sanyog Jain BSA-loaded chitosan nanoparticles were prepared and encapsulated in vesicles (liposomes and nio-somes) to make them acid resistant upon oral administration. Prepared systems were characterized in-vitro for shape, size, entrapment efficiency and stability in simulated gastric fluid (SGF, pH 1.2) and simulated intestinal fluid (SIF, pH 7.5). The immune stimulating activity was studied by measuring serum IgG titre and secretory IgA (sIgA) levels in mucosal secretions following oral administration of various formulations in albino rats. Significantly higher (P < 0.05) serum IgG titres were achieved following oral administration of novel nanoparticulate vesicular formulations as compared with unmodified chitosan nanoparticles. Further, high sIgA levels in mucosal secretions advocated a possible application of chitosan nanoparticle encapsulated in vesicles as an oral vaccine delivery carrier-adjuvant system. [source] The influence of morphine on the absorption of paracetamol from various formulations in subjects in the supine position, as assessed by TDx measurement of salivary paracetamol concentrationsJOURNAL OF PHARMACY AND PHARMACOLOGY: AN INTERNATI ONAL JOURNAL OF PHARMACEUTICAL SCIENCE, Issue 10 2003Julia M. Kennedy ABSTRACT The aim of this study was to determine the influence of the type of paracetamol formulation on the rate of absorption when subjects are in the supine position, with or without taking concomitant morphine. Two groups of healthy volunteers were used, who were in the fasting state and remained in the supine position during the study. One group took 1500 mg of paracetamol on three occasions as conventional tablets, dispersible tablets or a suspension in a randomized crossover design. Seventeen saliva samples per subject were obtained (time zero to 360 min post-dose), which were then centrifuged and kept at ,20°C prior to analysis. The second group repeated the study following four doses of morphine syrup (10 mg 4 hourly) in the 12 h preceding paracetamol ingestion. In this phase of the study, paracetamol absorption from suspension was not investigated. A TDx assay was used to determine salivary paracetamol concentrations. The tmax for conventional tablets when taken concomitantly with morphine was 160 (+81) min compared to 51 (+58) min for subjects not taking morphine. For dispersible tablets the tmax in the morphine group was 14 (+9) min compared to 15 (+12) min without morphine. The results suggest that patients who are confined to bed and taking morphine will have an unacceptably long delay between taking conventional paracetamol tablets and the paracetamol reaching therapeutic plasma concentrations. Conversely, there is little effect on the absorption of dispersible paracetamol under the same conditions. [source] The impact of silane chemistry conditions on the properties of wood plastic composites with low density polyethylene and high wood contentPOLYMER COMPOSITES, Issue 5 2010Yu Geng Silane chemistry was implemented on various formulations of wood/thermoplastic polymer composites (WPCs) with low density polyethylene (LDPE) and high wood content (60 wt%). Taguchi analysis was used to evaluate the impact of vinyltrimethoxysilane content (VTMS), dicumyl peroxide content (DCP), and processing temperature on the rheological, morphological, and dynamic mechanic properties of WPCs. The torque power was measured by a Haake torque rheometer and indicated that the VTMS content and temperature most significantly impacted the rheological properties related to silane reactions. Differential scanning calorimetry also showed a larger depression in LDPE melting point and crystallinity index when a high VTMS content (35 phr), high DCP content (0.5 phr), and a high compounding temperature (200°C) were used. With dynamic mechanical analysis (DMA), it was shown that the compounded formulations had a higher storage modulus over a wide range of temperature whereas the , transition temperature increased with higher content in silane reactants. Interestingly, the high humidity/temperature conditioning step aimed at crosslinking resulted in a drop of dynamic moduli compared to the freshly compounded formulations. This was explained by the fact that during compounding of LDPE with high wood content and silane reactants, significant amounts of matrix and interfacial silane crosslinking already occurred. Subsequent conditioning in a high humidity and temperature environment was proposed to hydrolyze the interfacial siloxane bonds resulting in a degradation of mechanical properties. POLYM. COMPOS., 2010. © 2009 Society of Plastics Engineers [source] Black Metropolis and Mental Life: Beyond the "Burden of ,Acting White' " Toward a Third Wave of Critical Racial StudiesANTHROPOLOGY & EDUCATION QUARTERLY, Issue 3 2008A. A. Akom In this article, I reflect on Signithia Fordham and John Ogbu's classic research on the "burden of ,acting White' " to develop a long overdue dialogue between Africana studies and critical white studies. It highlights the dialectical nature of Fordham and Ogbu's philosophy of race and critical race theory by locating the origins of the "burden of ,acting White' " in the work of W.E.B. Du Bois, who provides some of the intellectual foundations for this work. Following the work of F. W. Twine and C. Gallagher (2008), I then survey the field of critical whiteness studies and outline an emerging third wave in this interdisciplinary field. This new wave of research utilizes the following five elements that form its basic core: (1) the centrality of race and racism and their intersectionality with other forms of oppression; (2) challenging white supremacy, patriarchy, heteronormativity, and other dominant ideologies; (3) a critical reflexivity that addresses how various formulations of whiteness are situated in relation to contemporary formulations of Black/people of color identity formation, politics, and knowledge construction; (4) innovative research methodologies including asset-based research approaches; and, finally, (5) a racial elasticity that identifies the ways in which white racial power and pigmentocracy are continually reconstituting themselves in the color-blind era and beyond (see A. A. Akom 2008c).[oppositional identity, Black student achievement, youth development, acting white, Du Bois, critical whiteness studies, critical race theory, race, Black metropolis, double consciousness, twoness, hip-hop] [source] Effect on absorption and oxidative stress of different oral Coenzyme Q10 dosages and intake strategy in healthy menBIOFACTORS, Issue 1-4 2005R. B. Singh Abstract Introduction: The effect of various dosages and dose strategies of oral coenzyme Q10 (Q10) administration on serum Q10 concentration and bioequivalence of various formulations are not fully known. Subjects and Methods: In a randomized, double blind, placebo controlled trial 60 healthy men, aged 18,55 years, were supplemented with various dosages and dose strategies of coenzyme Q10 soft oil capsules (Myoqinon 100 mg, Pharma Nord, Denmark) or crystalline 100 mg Q10 powder capsules or placebo. After 20 days blood levels were compared and oxidative load parameters, malondialdehyde (MDA) and thiobarbituric acid reactive substances (TBARS) were monitored to evaluate bioequivalence. All the subjects were advised to take the capsules with meals. Blood samples were collected after 12 hours of overnight fasting at baseline and after 20 days of Q10 administration. Compliance was evaluated by counting the number of capsules returned by the subjects after the trial. Results: Compliance by capsule counting was >90%. Side effects were negligible. Serum concentrations of Q10 (average for groups) increased significantly 3,10 fold in the intervention groups compared with the placebo group. Serum response was improved with a divided dose strategy. TBARS and MDA were in the normal ranges at baseline. After 20 days intervention in the 200 mg group TBARS and MDA decreased, but the decrease was only significant for MDA (Fig. 2). Conclusions: All supplementations increased serum levels of Q10. Q10 dissolved in an oil matrix was more effective than the same amount of crystalline Q10 in raising Q10 serum levels. 200 mg of oil/soft gel formulation of Q10 caused a larger increase in Q10 serum levels than did 100 mg. Divided dosages (2 × 100 mg) of Q10 caused a larger increase in serum levels of Q10 than a single dose of 200 mg. Supplementation was associated with decreased oxidative stress as measured by MDA-levels. Indians appear to have low baseline serum coenzyme Q10 levels which may be due to vegetarian diets. Further studies in larger number of subjects would be necessary to confirm our findings. [source] Impact of freezing on pH of buffered solutions and consequences for monoclonal antibody aggregationBIOTECHNOLOGY PROGRESS, Issue 3 2010Parag Kolhe Abstract Freezing of biologic drug substance at large scale is an important unit operation that enables manufacturing flexibility and increased use-period for the material. Stability of the biologic in frozen solutions is associated with a number of issues including potentially destabilizing pH changes. The pH changes arise from temperature-associated change in the pKas, solubility limitations, eutectic crystallization, and cryoconcentration. The pH changes for most of the common protein formulation buffers in the frozen state have not been systematically measured. Sodium phosphate buffer, a well-studied system, shows the greatest change in pH when going from +25 to ,30°C. Among the other buffers, histidine hydrochloride, sodium acetate, histidine acetate, citrate, and succinate, less than 1 pH unit change (increase) was observed over the temperature range from +25 to ,30°C, whereas Tris-hydrochloride had an ,1.2 pH unit increase. In general, a steady increase in pH was observed for all these buffers once cooled below 0°C. A formulated IgG2 monoclonal antibody in histidine buffer with added trehalose showed the same pH behavior as the buffer itself. This antibody in various formulations was subject to freeze/thaw cycling representing a wide process (phase transition) time range, reflective of practical situations. Measurement of soluble aggregates after repeated freeze,thaw cycles shows that the change in pH was not a factor for aggregate formation in this case, which instead is governed by the presence or absence of noncrystallizing cryoprotective excipients. In the absence of a cryoprotectant, longer phase transition times lead to higher aggregation. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2010 [source] | ||||||||||||||||