Concurrent Determination of Pridinol, Diclofenac and Impurity A by HPLC-UV.

A reversed-phase high-performance liquid chromatography method was developed and validated for the simultaneous determination of pridinol, diclofenac and diclofenac-related compounds in tablet formulations. The proposed method is also suitable for content uniformity determination, for dissolution test and for stability studies. Separation was achieved on a base-deactivated silica C8 column, using 50 mM phosphate buffer (pH 2.

Paramylon and synthesis of its ionic derivatives: Applications as pharmaceutical tablet disintegrants and as colloid flocculants.

Paramylon, a high molecular weight polysaccharide, is a linear and unbranched (1 → 3)-β-d-glucan. Despite its numerous biological benefits, the poor aqueous solubility of crystalline paramylon is a drawback that has hampered some of its applications. In an effort to make this biomaterial amenable to practical uses, cationic and anionic paramylon derivatives were obtained.

Carrageenans from Sarcothalia crispata and Gigartina skottsbergii: Structural Analysis and Interpolyelectrolyte Complex Formation for Drug Controlled Release.

The aims of the present study were to characterize for the first time the carrageenan extracted from cystocarpic stage of S. crispata collected in the Patagonian coast of Argentina, and to prepare interpolyelectrolytic complexes (IPECs) between the polysaccharide extracted from cystocarpic stage of Sarcothalia crispata and Gigartina skottsbergii thalli, and basic butylated methacrylate copolymer (Eudragit E), in order to test their potential for the controlled release of ibuprofen as model drug. The structural determination revealed that the polysaccharides extracted from S.

Development and in vitro evaluation of potential electromodulated transdermal drug delivery systems based on carbon nanotube buckypapers.

Buckypapers based on different types of carbon nanotubes with and without the addition of four model drugs, two of basic nature (clonidine hydrochloride, selegiline hydrochloride) and the others of acidic character (flurbiprofen, ketorolac tromethamine) were prepared and characterized. The influence of the conditions employed in the preparation of the buckypapers (dispersion time and solvents used in the preparation, as well as the type of carbon nanotubes used and the characteristics of the drug involved) on their conductivity was especially examined. The in vitro performance of the drug loaded buckypapers as passive and active transdermal drug release systems, the latter being modulated by means of the application of electric voltages, was studied.

Carbon nanotubes buckypapers for potential transdermal drug delivery.

Drug loaded buckypapers based on different types of carbon nanotubes (CNTs) were prepared and characterized in order to evaluate their potentialities for the design of novel transdermal drug delivery systems. Lab-synthesized CNTs as well as commercial samples were employed. Clonidine hydrochloride was used as model drug, and the influence of composition of the drug loaded buckypapers and processing variables on in vitro release profiles was investigated.

Cationization of kappa- and iota-carrageenan--Characterization and properties of amphoteric polysaccharides.

Commercial kappa- and iota carrageenans were cationized with 3-chloro-2-hydroxypropyltrimethylammonium chloride in aqueous sodium hydroxide solution. For kappa-carrageenan three derivatives with different degrees of substitution were obtained. Native and amphoteric kappa-carrageenans were characterized by NMR and infrared spectroscopy, scanning electron and atomic force microscopy; methanolysis products were studied by electrospray ionization mass spectrometry.

Preparation and characterization of controlled release matrices based on novel seaweed interpolyelectrolyte complexes.

Novel interpolyelectrolyte complexes (IPECs) between naturally sulfated polysaccharides of the seaweed Polysiphonia nigrescens (PN) and cationized agaroses (CAG) and Eudragit E (EE) were prepared using an organic solvent free process, characterized, and explored for controlled drug release. Tablets containing model drug ibuprofen and IPECs were prepared by direct compression. Drug release in acid medium was low owing to the low solubility of ibuprofen in that condition and to the matrix action.

Studies on the cationization of agarose.

Cationized agaroses with different degrees of substitution (0.04-0.77) were synthesized, employing 3-chloro-2-hydroxypropyltrimethylammonium chloride (CHPTAC).

Preparation and characterization of a novel starch-based interpolyelectrolyte complex as matrix for controlled drug release.

A novel cationized starch-based interpolyelectrolyte complex (IPEC) was formed using kappa-carrageenan as the counter polyion. Characterization of the product by turbidity measurements and elemental analyses indicated a 1:1 interaction of the repeating units. FT-IR spectra for the IPEC showed some differences in comparison with either IPEC constituents or physical mixture.

Agarans from the red seaweed Polysiphonia nigrescens (Rhodomelaceae, Ceramiales).

Polysiphonia nigrescens was sequentially extracted with water at room temperature, 70 and 90 degrees C. The extracts were analyzed and the major one, isolated at 70 degrees C, was fractionated by ion-exchange chromatography, eluting with water and solutions of increasing sodium chloride concentration; five main fractions were separated. Structural analysis, carried out by methylation analysis and NMR spectroscopy, showed that four of these were partially cyclized agarans that were highly substituted on C-6 mainly with sulfate, although methyl ether and single stubs of beta-D-xylose were found in minor proportions.