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In mixer granulation, power consumption measurement of the mixer motor was established to be a valuable tool in order to estimate an uncritical quantity of granulating liquid. The mid-point of the plateau phase, which may be found with the power consumption profile in the pendular state of liquid saturation, is frequently applied as a measure of the optimum concentration of the binder solution in...
The medium chain fatty acid sodium caprate (C10) enhances paracellular drug flux by increasing the permeability of the tight junctions. However, its onset and mechanism of action has not been studied in great detail. Thus, the only study dealing with the mechanism of C10 was performed after 60 min incubation - a time point too late to be of significance in the in vivo situation. The aim of this...
Hypericin, a naturally occuring naphthodianthrone, is isolated from plant extracts of the Hypericum genus, which are used as antidepressants. Due to its antiretroviral effects observed in vitro as well as in vivo, hypericin is recently under investigation as a therapeutic tool against retroviral induced diseases such as AIDS. Hypericin is practically insoluble in water and hence for pharmacological...
Conventional wet processing of drug and excipient powders into granules for use in tableting or capsule filling requires up to six different unit operations and eight materials transfers. In order to be competitive with the simplest processing technology, direct compression, which requires just two unit operations, the number of manipulations required in wet processing should be reduced. Our aim...
There are several clinical conditions, for example endometrial hyperplasia and post-menopausal hormone replacement therapy, for which sustained, local delivery of progestogens to the uterus may be advantageous due to the reduction of systemic effects. We have previously reported the development of a drug-releasing nylon hollow fibre small enough for easy passage through the cervix and capable of...
One recent development in the field of drug delivery has been the inclusion of stealth lipids in liposome formulations. Sterically stabilised liposomes (SSL) often avoid the reticulo-endothelial system (RES) for longer periods than conventional liposomes, leading to an enhanced blood-circulation time. Although such vesicles are also quite stable in suspension form compared to conventional vesicles,...
Snake skin has been used to model the barrier nature of human skin to drugs since it presents negligible biohazard and the snake sheds its skin periodically thus avoiding need for sacrifice. However, there are anatomical differences between human stratum corneum, with its keratinised cells embedded in a multiply bilayered lipid matrix and appendages, and snake epidermis with a hinge and scale construction...
A series of 5 artificial neural networks (ANN) have been developed for use in the sequence-based prediction of a protein's structural class and 'working environment'; the latter categorization distinguishing between transmembrane (TM) and soluble proteins, and the former between all-α, all-β and non-α, non-β proteins. The ANN were trained using data for 47 protein chains with known 3-D structure...
Water vapour affects the majority of pharmaceutically active compounds, often leading to deleterious chemical and/or physical changes. For most dosage forms it is relatively easy to control the water content. The problems are however compounded for injectable products due to the requirement to maintain product purity and sterility. A number of novel methods of drying the contents of injection vials...
Nanoparticles have been studied as carriers that improve the absorption of peptides via the gastrointestinal tract. Many peptides are highly water soluble, however, hardly any nanoparticles are suitable for them. In this study, nanoparticles capable of encapsulating hydrophilic peptides were developed.Nanoparticles were prepared by the dispersion copolymerization of hydrophilic macromonomers such...
The sense of smell is highly evocative, sensitive and discriminating. Changes in the aroma of a pharmaceutical product may not necessarily be associated with a deterioration in its therapeutic quality or efficacy. However they are often readily detectable by the patient. The aroma of a pharmaceutical is therefore a percieved quality parameter worthy of careful study and quantification.Recent developments...
One of the ways to alter the cellular uptake and transport pattern of drugs is to couple them with biocompatible polymers. The Bowman-Birk soybean proteinase inhibitor (BBI) is a protein of low Mr (8 kDa). BBI is considered as a promising antiproteolytic and anticarcinogen agent. The main drawback of BBI is rapid clearance from circulation, t12 = 3.9 min.The goal of present work was to synthesize...
Cremophor(R) EL (IUPAC-nomenclature: α-Hydro-ω-hexadecyloxypoly-(oxyethylen)) is obtained from 1 mol castol oil and 35 mol ethylene oxide as a multicomponent mixture and is commonly used as nonionic emulgent and solubiliser in order to prepare aqueous solutions of hydrophobic substances. Cremophor EL can be used for manufacturing parenteralia since it does not cause haemolysis, but various other...
The grafting of hydrophilic macromolecules such as polyethylene glycol or dextran to therapeutic proteins has proved successful in prolonging their presence in the blood and reducing their immunogenicity. In this respect, biodegradable N-acetylneuraminic acid polymers (polysialic acids) have been proposed as an alternative. Recently, bovine liver catalase (E.C. 1.11.1.6) was covalently linked to...
Human skin is preferred as membrane for the in vitro evaluation of transdermal systems, but it is not readily available and ethical problems are related to its use. Moreover great variability exists between specimens of different individuals, body sites and methods of collection. Following these considerations a reliable model to use instead of human skin is a highly desirable goal.Animals skins,...
The isolated hindlimb of the rat has been used to carry out an study of the distribution kinetics of two quinolones: ofloxacin and ciprofloxacin. The experimental preparation has been previously defined in terms of its qualitative and quantitative tissue composition as well as the regional flow rates.Female rats of 160.69+/-19.39 g of mean body weight were used in order to minimize the presence of...
Several cyclodextrins (CyDs) and selected derivatives (hydroxyalkylated-β-CyDs, α-CyD polymer and carboxymethylated α-CyD polymer) which can be applicated onto the eye have been investigated with the aim to get information about their influence on the in vitro and in vivo availability of pilocarpine - a common and well known antiglaucomatous drug.The in vitro results have been compared with commercial...
Usually pellets obtained from extrusion/spheronization do not tend to disintegrate. However it was possible to produce disintegrating pellets by using a combination of a suitable disintegrant with a granulation liquid containing a high fraction of 2-propanol. The reduction of water necessary for extrusion was thought to be a main reason for the disintegration. The tested formulation contained 60%...
Surfactant containing multicomponent systems, especially microemulsions, achieve interest as potential pharmaceutical formulations because of their thermodynamic stability and their properties in view of solubilisation and release of drugs.A transparent, fluid and thermodynamically stable multicomponent system consisting of polyoxyethylene glycol ester of stearinic acid (Tagat S(R)), polyglycerol...
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