Determination of the binding constant of indomethacin-beta-cyclodextrin complex by capillary electrophoresis: experimental optimization and temperature study.

The apparent electrophoretic mobilities of indomethacin in beta-cyclodextrin at a range of concentrations were measured directly by capillary electrophoresis. Three different linear plots and a non linear plot are proposed for the apparent binding constant calculations, based on the fact that the molar ratio of the inclusion complex was 1:1. K values obtained at 298 K were 421 M(-1) (double reciprocal fit), 488 M(-1) (x-reciprocal fit), 428 M(-1) (y-reciprocal fit) and 490 M(-1) (non linear fit). The corresponding K values at 313 K were 380 M(-1) (double reciprocal fit), 355 M(-1) (x-reciprocal fit), 366 M(-1) (y-reciprocal fit) and 339 M(-1) (non linear fit). Using the proposed methods, the binding constant of the indomethacin-beta-cyclodextrin inclusion complex can be obtained easily. The methods have been applied to obtain the values of the constant K under different experimental conditions. Under optimized conditions the K constant is temperature dependent and non-arrhenian behaviour was observed.

Fingerprint analysis and synthetic adulterant search in Hedera helix formulations by capillary electrophoresis.

A high-performance capillary electrophoretic (CE) method has been developed for obtaining electropherograms of various extracts and the commercial formulation (fingerprints) of Hedera helix L used in Argentina as a cough's treatment. Also, a capillary zone electrophoresis (CZE) method was developed for the search, identification and determination of some possible adulterants. These likely adulterants are common synthetic drugs used in respiratory diseases (antitussive, decongestant and bronchodilator agents). Under optimum conditions, the analytes (ephedrine, codeine, diphenhydramine and constituents of H. helix formulations) were separated within less than 10 min in 20 mM sodium tetraborate buffer (pH 9.0). The present procedure was validated with respect to selectivity, linearity range, limits of detection (LOD) and quantification (LOQ), precision (repeatability and intermediate precision), solution stability and accuracy; the results obtained were satisfactory. Good linearity was obtained over two orders of magnitude and detection limits (S/N = 3) were better than 1.2 microg ml(-1) for all analytes. The CE methodology was successfully applied to the search and subsequent determination of ephedrine, codeine and diphenhydramine in H. helix extracts and its phytopharmaceutical products.

Determination and assay validation of the bioactive sesquiterpene lactone xanthatin isolated from Xanthium cavanillesii using capillary electrophoresis.

This study describes the development and validation of a method for quantification of the antiulcer experimental drug xanthatin in tablets by capillary electrophoresis (CE). Solid oral dosage forms based on xanthatin were designed and assayed on rats. A CE methodology was developed; the parameters evaluated were: background electrolyte composition, concentration and pH, applied voltage and sample preparation. The method was validated in terms of range of linearity, limits of detection (LOD) and quantification (LOQ), accuracy, precision and selectivity and then applied to the pharmaceutical dosage forms. Xanthatin determination was carried out in less than 3 min with a 20 mM sodium tetraborate buffer, pH 9.20. Drug concentration per tablet found was 2.97 +/- 0.2 mg. Calibration plots were linear over at least three orders of magnitude of analyte concentrations, LOD and LOQ were 7.6 and 26 microg mL(-1) respectively. For accuracy evaluation a recovery test was performed, the values being better than 98.6%. With respect to precision, the results obtained were better than 1.02 RSD% (repeatability) and 1.54% (intermediate precision). After the manufacturing process the resulting tablets were biologically active. The methodology developed is useful, simple and rapid for xanthatin determination in tablets.

Practical aspects of achieving positive energy balance in low birth weight infants.

For the low birth weight (LBW) infant, energy balance during the first several days of life usually is equated to absorption of sufficient energy to match energy expenditure. Most studies show that energy expenditure of nongrowing LBW infants is 45 to 55 kcal/kg/day. Hence, for energy equilibrium, energy intake minus energy losses (i.e., metabolizable energy intake) must be at least 50 kcal/kg/day. Intakes above this amount result in energy storage or positive energy balance, whereas lesser intakes necessitate mobilization of endogenous energy stores (negative energy balance). Some of the problems of achieving positive energy balance in LBW infants (e.g., feeding intolerance and fear of necrotizing enterocolitis) can be circumvented by use of parenterally delivered nutrients. On balance, virtually all LBW infants will tolerate parenteral amino acid, glucose, and lipid intakes, respectively, of 2, 5, and 1 gm/kg/day or an energy intake of about 40 kcal/kg/day. It usually is possible to increase energy intake of most infants by an additional 10 kcal/kg/day. Whether this is achieved with enterally delivered nutrients or additional parenteral glucose or lipid intake, including the necessary modifications to enhance tolerance (e.g., insulin, 20% vs 10% lipid emulsions, and lipid emulsions containing medium-chain fatty acids), must be decided for each infant based on his or her underlying condition, likelihood of tolerating either substrate, and the impact of intolerance on the underlying condition. The consequences of not providing an essential nutrient during the immediate postnatal period also must be considered. The fact that essential fatty acid deficiency develops more rapidly in infants receiving isocaloric (60 kcal/kg/day) parenteral intakes with versus without amino acids, the likelihood that brain growth continues despite negative energy balance, and the possibility that LBW infants may not be able to desaturate/elongate linoleic and linolenic acids to the more unsaturated, longer-chain fatty acids that are deposited in the developing brain suggest that these infants may require exogenous intakes of specific fatty acids.

Distrofia de las veinte uñas / Dystrophy of the 20 nails

Presentamos 3 casos de DVU,2 niños y un adulto; uno de ellos - 12 años de edad - con cuadro histopatológico típico de la DVU idiopática. Comentamos la asociación con otras enfermedades, uno de nuestros casos - 50 años de edad - presentó AA. El tercer paciente - 4 años de edad - corresponde a la DVU del grupo I de Samman (1978)

Distrofia de las veinte uñas / Dystrophy of the 20 nails

Presentamos 3 casos de DVU,2 niños y un adulto; uno de ellos - 12 años de edad - con cuadro histopatológico típico de la DVU idiopática. Comentamos la asociación con otras enfermedades, uno de nuestros casos - 50 años de edad - presentó AA. El tercer paciente - 4 años de edad - corresponde a la DVU del grupo I de Samman (1978) (AU)

Occupational health in Cuba.

Health and safety regulation, training, and research were practically non-existent in Cuba before the Revolution in 1959. Since that time important advances have been made. Specialized inspectors, occupational physicians, and other such personnel are now trained in Cuba. An Occupational Health Institute, founded in 1976, provides training and specialized technical services, and conducts research. In 1978, a far reaching "Work Safety and Health Law" was enacted which defines the rights and responsibility of government agencies, workplace administrators, unions, and workers. Comprehensive control of toxic substances in workplaces, still at an early stage, is likely to increase in light of the new law, the growing availability of qualified personnel, and the mounting concern of public health authorities with the increasingly "developed" health profile of the population.