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Biomedical subjects

P Solich

Publications and source records attributed to P Solich.

15 recordsLinked to original sources
PubMed2004

Simultaneous HPLC determination of ketoprofen and its degradation products in the presence of preservatives in pharmaceuticals.

A novel and quick high-performance liquid chromatography (HPLC) method with UV spectrophotometric detection was developed and validated for the determination of five compounds in topical gel. The described method is suitable for simultaneous determination of active component ketoprofen, two preservatives methylparaben and propylparaben and two degradation products of ketoprofen--3-acetylbenzophenone and 2-(3-carboxyphenyl) propionic acid--in a topical cream after long-term stability tests using ethylparaben as an internal standard. The chromatographic separation was performed on a 5microm Supelco Discovery C18 column (125mm x 4mm i.d., Sigma-Aldrich); the optimal mobile phase for separation of ketoprofen, methylparaben, propylparaben, degradation products 3-acetylbenzophenone and 2-(3-carboxyphenyl) propionic acid and ethylparaben as internal standard consists of a mixture of acetonitril, water and phosphate buffer pH 3.5 (40:58:2, v/v/v). At a flow rate of 1.0ml min(-1) and detection at 233nm, the total time of analysis was less than 10min. The method was applied for routine analysis (batch analysis and stability tests) of these compounds in topical pharmaceutical product.

Chromatography, High Pressure Liquid↗
PubMed2004

Sensitive fluorimetric method based on sequential injection analysis technique used for dissolution studies and quality control of prazosin hydrochloride in tablets.

This report introduces a fully automated flow system for drug-dissolution studies based on the coupling of the sequential injection analysis (SIA) technique with a conventional dissolution apparatus. The methodology described was used for monitoring of dissolution profiles of prazosin hydrochloride (PRH) in pharmaceutical formulation. The very sensitive fluorimetric detection of PRH was performed at lambda(ex)=244 nm (lambda(em)>or=389 nm). Under the optimal conditions, the calibration curve was linear over the range 0.02-2.43 mg x l(-1) of PRH with R.S.D. 1.89, 1.23, and 1.80% (n=10) when determining 0.02, 1.22, and 2.43 mg x l(-1) of PRH in standard solutions, respectively. Equation of the calibration curve was calculated giving the following values: F=4.108 c-3.9 (n=6), r=0.9996. Detection limit was calculated 0.007 mg x l(-1) of PRH. The dissolution test of Deprazolin tablets was programmed for 60 min, with a continuous sampling rate of 70 h(-1) under conditions required by USP 26. Results obtained by SIA technique compared well with HPLC standard method.

Chromatography, High Pressure Liquid↗
PubMed2004

[Oxidative determination of rutin in tablets using flow injection analysis and chemiluminescence].

A simple, rapid and fully automated flow injection method (FIA) with chemiluminescence detection after oxidation with KMnO4 in acid medium at room temperature has been developed for the determination of routine in pharmaceutical formulation. Hexamethaphosphate sodium was utilized as enhancer of chemiluminescence. The calibration curve was linear in the range 0.01-0.26 mmol.l-1 with detection limit 0.005 mmol.l-1, RSD 0.46% (n = 10) and a sample throughput of 75.h-1 using a 200 microliters sample volume. The method was used for the determination of routine in mass-produced dosage form: Rutin 250 tablets á 50 mg, (firm Nature's Bounty, USA). The FIA method was statistically compared with the official German Pharmacopoeia method and showed comparable accuracy, but with the advantages of simplicity, speed and amounts of reagents consumed.

Flow Injection Analysis↗
PubMed2003

Simultaneous determination of methylparaben, propylparaben, hydrocortisone acetate and its degradation products in a topical cream by RP-HPLC.

A novel reversed-phase high-performance liquid chromatographic method with UV spectrophotometric detection was developed and validated for the determination of compounds in topical cream. The method describes determination of active component hydrocortisone acetate (HCA), its degradation products hydrocortisone (HC) and cortisone acetate (occurring in formulation after long-term stability tests) and two preservatives presented in the cream-methylparaben and propylparaben, using dexamethasone as an internal standard. The chromatographic separation was performed on a 5 microm SUPELCO Discovery C18 125 x 4-mm ID column. The optimised mobile phase for separation of all the compounds consists of methanol, acetonitrile and water (15:27:58, v/v/v), with the analysis time less than 13 min. The method was applicable for routine analysis (assays and stability tests) of active compound HCA, preservatives and degradation products in pharmaceutical product--topical cream Hydrocortizone cream 1%.

Administration, Topical↗
PubMed2003

Determination of methylparaben, propylparaben, triamcinolone acetonide and its degradation product in a topical cream by RP-HPLC.

A novel reversed-phase high-performance liquid chromatographic (RP-HPLC) method was developed and validated for the determination of active component triamcinolone acetonide, its degradation product triamcinolone (occurring in formulation after long-term stability tests) and two preservatives presented in the cream-methylparaben and propylparaben, using hydrocortisone as an internal standard. The chromatographic separation was performed on a Supelco Discovery C18 column; the mobile phase for separation of all compounds consists of a mixture of acetonitrile and water (40:60 v/v). The analysis time was less than 9 min, at a flow rate of 0.6 mL min(-1) and detection at 240 nm. The method was found to be applicable for routine analysis (stability tests, homogeneity) in the pharmaceutical product topical cream Triamcinolon cream 0.1%.

Administration, Topical↗
PubMed2001

Simultaneous determination of quercetin, kaempferol and (E)-cinnamic acid in vegetative organs of Schisandra chinensis Baill. by HPLC.

A reversed-phase high-performance liquid chromatographic (RP-HPLC) separation method with UV spectrophotometric detection has been developed for the determination of major components in leaves and caulomas of Schisandra chinensis Baill. The flavonols (quercetin and kaempferol) and (E)-cinnamic acid were analysed after extraction with alcohol from the dry plant material. Identification was based on retention times and UV spectra by comparison with commercial standards. Quercetin, kaempferol and (E)-cinnamic acid were separated within 12 min using acetonitrile-aqueous 0.05% ortho-phosphoric acid (40:60 v/v) mobile phase. The method has been successfully applied for the quantitative analysis of all three major components in several samples from different harvests using propylparaben as the internal standard.

Chromatography, High Pressure Liquid↗
PubMed2001

Application of automated flow injection analysis to drug liberations studies with the Franz diffusion cell.

The flow-injection method with sensitive fluorimetric detection is used to monitor the liberation profiles of a topical dermatological formulation containing the model compound salicylic acid. The connection of a standard Franz diffusion cell with the automated flow-injection system enables an acquisition of multi-point liberation data in a form of series of fluorescence peaks in a short time. Examples of liberation profiles for a topical dermatological formulation containing salicylic acid are shown.

Autoanalysis↗
PubMed2000

Automated flow-injection spectrophotometric determination of catecholamines (epinephrine and isoproterenol) in pharmaceutical formulations based on ferrous complex formation.

A novel automated flow-injection spectrophotometric method for the determination of catecholamines (epinephrine and isoproterenol) has been developed based on the formation of their coloured complexes with Fe(II) in aminoacetic-carbonate buffer pH 8.3 and measuring of the absorbance peaks at the lambda(max) of 530 nm. A fully automated FIA system controlled by home-made software (FIA-MOD) was used for optimising the chemical and manifold parameters and running of routine measurements. The calibration graph was linear in the range of 5-200 mg l(-1) for epinephrine with an RSD of 0.24% (n = 5; c = 150 mg l(-1)) and 10-300 mg(-1) for isoproterenol with an RSD of 0.13% (n = 5; c = 200 mg l(-1)). Measurement throughput was 120 h(-1) ensuring a sample throughput of 40 h(-1) analysed in triplicate. Common excipients for tablets and injections were found not interfering. The proposed method was applied for the assay of various commercial pharmaceutical formulations containing epinephrine and isoproterenol and for the content uniformity test for the isoproterenol tablets. The assay results with RSD 2-4% (n = 3) were comparable with those obtained with the official USP XXIII methods (mean difference 1.9%).

Artifacts↗
PubMed2000

20-Hydroxyecdysone release from biodegradable devices: the effect of size and shape.

20-Hydroxyecdysone (20-OH) is a natural compound with many demonstrated effects on the physiological functions of vertebrates, particularly increased protein synthesis. Our study sought a suitable dosage form with continuous release of the drug lasting several weeks for implantation into agricultural animals. Biodegradable microparticles and implants of poly(L-lactic) and poly(DL-lactic) acids were prepared. Oligomers of these materials were synthesized, and a method of melting the binary mixture of the oligomer and 20-OH was employed. The particles were prepared simply by grinding the solidified block of the melt and sieving. Implants were prepared by extruding the melt into silicone tubes, removing the solidified content, and cutting into cylinders of 2 mm diameter and various lengths. A new method of preparation of hollow cylinders by aspirating air into silicone tubes filled with the melt was developed. The experiments demonstrated stability of 20-OH during heat treatment. Release of the active ingredient was tested in static in vitro conditions, analogous to those at the site of implantation, and prolonged drug release was obtained with both types of implant. The hollow implants gave release rates nearest to ideal zero-order kinetics and would appear most appropriate for testing in vivo.

Absorbable Implants↗
PubMed1999

Flow-injection fluorimetric determination of 1,4-benzodiazepines in pharmaceutical formulations after acid hydrolysis.

A simple, rapid and fully automated flow injection method with fluorimetric detection after hydrolysis with H2SO4 in ethanolic or methanolic medium at room temperature has been developed for the determination of 1,4-benzodiazepines (oxazepam, diazepam and nitrazepam) in pharmaceutical formulations. The calibration curves are linear in the ranges (mg ml(-1)) of oxazepam (0.025-0.150), diazepam (0.010-0.125) and nitrazepam (0.010-0.150), with detection limits of 0.01, 0.005 and 0.005 mg ml(-1), respectively, and RSD (1% (n = 10). The measurement throughput is 60 h(-1) using a 200-microl sample volume obtained by the direct dissolution of formulations in alcohol.

Anti-Anxiety Agents↗
PubMed1997

[Phytotherapeutic aspects of diseases of the circulatory system. 6. Leuzea carthamoides (WILLD.) DC: the status of research and possible use of the taxon].

Leuzea carthamoides (WILLD.) DC., Asteraceae, has become an important taxon usable in human practice and animal production in recent years. Originally an endemic plant of southern Siberia, now it is widely grown not only in the Union of Independent States, once the original region of introduction, but also in central and eastern Europe. The principal constituents of the whole plant are ecdysteroids (5 beta-cholest-6-on-7-ene derivatives) and flavonoids. In addition, the aerial part contains sesquiterpenic lactones of the guajanolide type, and the roots contain polyines (on the thiophene base). The present paper comprehensively discusses the occurrence, content and biological activity of these substances, the preparations manufactured from the plant, their use in therapeutic practice, food manufacture and animal production in the world and the Czech Republic. The plant has certainly become a taxon with prospects in the Czech Republic, particularly as the source of 20-hydroxyecdysone, which is getting into the limelight in the world.

Animals↗
PubMed1995

Construction of a diflunisal ion sensor and its use in automated flow-injection methods for assay, content uniformity, and dissolution studies of formulations.

A diflunisal ion selective electrode of the PVC membrane type with an ion-exchanger consisting of the tetraheptylammonium-diflunisal ion pair is described. The sensor exhibits a rapid, near-Nernstian, selective response to diflunisal anion in the pH range 7-10, with a (batch) detection limit of 1 x 10(-5) M. The ion sensor was used as a flow detector in an automated flow-injection analyzer to develop routine methods for assays (concentration range 1-50 x 10(-4) M, (flow) detection limit 2.6 x 10(-5) M), content uniformity, and dissolution studies of diflunisal formulations. No serious interference from common ions and tablet excipients was found, and the drug can be directly determined in colored samples without separation steps. Fourty measurements can be performed automatically per hour with a precision of 0.5-1.8% relative standard deviation. The automated method for the dissolution test provides a complete dissolution profile by the end of the experiment. Using the constructed ion sensor, the intramolecular hydrogen bonding of the diflunisal anion was studied, thereby revealing a new application of ion sensor potentiometry.

Electrodes↗
PubMed1994

[CADISO (Cardiovascular Diseases and Stability of the Organism): 10 years of integrated research on natural substances at the Charles University Pharmacy School in Hradec Králové].

The research project CADISO (Cardiovascular Diseases and Stability of the Organism--Phytotherapeutical Possibilities) is an alliance board associating approximately 20 professional institutions, its centre and coordinating laboratory being the Department of Pharmaceutical Botany and Ecology, Faculty of Pharmacy, Charles University, Hradec Králové. It aims at the prevention (additives in food industry) and therapy of diseases of the circulatory apparatus using phytotherapeutic agents and substances isolated from higher plants and fungi. The project is divided into three systems of investigation: ADAPRETE, i.e. the substances increasing the nonspecific resistance of the organism (adaptogenes of plant origin, immunostimulants), DIACORD, dealing with the substances acting on the cardiovascular system in a mediated way, i.e. treating the diseases the eventual action of which alters the heart and vessels (antihypercholesterolemics, antihyperlipidemics, antidiabetics, anti-oxidants and quenchers of free radicals, hepatoprotectives, anti-aggregating agents), and CORCORAN studying the taxons and substances isolated from them which act directly on the circulatory system (cardiotonic, anti-arrhythmic and vasodilating agents). To achieve a real purpose of the project, the linking-up of the phytochemical, pharmacological-toxicological, pharmaceutical-technological fields, production of raw materials and legislation is ensured.

Cardiovascular Diseases↗