Health-related quality of life among children and adolescents: associations with obesity.

OBJECTIVE: To assess the impact of obesity on health-related quality of life (HRQOL) of children, and to compare HRQOL scores of obese children in a hospital versus community setting. DESIGN: A cross-sectional study in two clinical samples. SUBJECTS: A total of 182 children and adolescents recruited from the community pediatric clinics and a hospital-based obesity clinic. MEASUREMENTS: Obesity was defined as body mass index (BMI) >95th percentile for age and gender. Subjects were divided into quartiles of BMI Z-scores each containing 45 or 46 children. The first two quartiles correspond to normal BMI, 3rd and 4th quartiles represent moderate and severe obesity, respectively. HRQOL was assessed by the Pediatric Quality of Life Inventory (PedsQL) questionnaire submitted by both children and their parents. RESULTS: Obese children reported significantly lower HRQOL in physical, social and school domains compared with normal weight children (P<0.01). Analyzing results of HRQOL by BMI quartiles showed that the emotional and school domains scores of the moderately obese children were similar to the normal BMI quartiles. Only in the 4th quartile, that of children with severe obesity, were scores significantly lower. In contrast, in both physical and social domains scores decreased progressively with increased BMI Z-scores. In the obese group, parents' scores were lower than the children's in all domains. HRQOL scores of obese children assessed in the hospital clinic were similar to that of obese children assessed in the community. CONCLUSIONS: Moderately obese children had similar emotional and school HRQOL scores as normal weight children, whereas in the physical domain, a significant difference was documented even in moderate obesity. Parents of obese children perceived their child's HRQOL lower than the children themselves. We believe that intervention programs aimed at improving HRQOL should be directed to both parents and children. Understanding the resilience of moderately obese children in school and emotional domains may assist us in the management of childhood obesity.

Formulation effects on the mechanical properties of metronidazole tablets.

The individual and interaction effects of nature of binder (N), concentration of binder (C) and the physical form of the formulation (P) on the tensile strengths (T--a measure of the bond strength of tablets) and the brittle fracture index values (BFI--a measure of the lamination tendency of tablets) of metronidazole tablets have been studied using a 2(3) factorial experimental design in each case. Changing binder concentration from a 'low' to a 'high' level increased T and reduced the BFI of the tablets. Methylcellulose 20 exhibited stronger binding effect and greater ability to reduce the lamination tendency of the tablets than polyvinylpyrrolidone of molecular weight 44,000. Granular formulations produced tablets with lower T values but also with lower BFI values than tablets produced from powdered formulations. The ranking of these individual effects on tensile strength was P greater than C greater than N while the ranking for the BFI was P greater than N greater than C. For the interaction effects, the ranking for tensile strength was P-N much greater than N-C greater than P-C while the ranking for the BFI was N-C much greater than P-C greater than P-N.

[Metabolic studies in reactive hypoglycemia].

Idiopathic reactive hypoglycemia is a rare and controversial entity. We present a 56-year-old woman with attacks of faintness after meals containing sugar. Postprandial hypoglycemia was found and was diagnosed as idiopathic reactive hypoglycemia. She did not suffer any attacks after sugar was eliminated from her diet.

Effect of particle shape on the mixing of powders.

Mixtures were prepared containing 200 g of 600 microns lactose and 0.5 g of 3 microns calcium carbonate of different particle shapes using a Y cone mixer. Measurements were made of the time required to achieve the acceptable standard deviation of mixing sigma A and of the segregation that occurred on subsequently vibrating the mixtures. The time taken to achieve sigma A increased with the irregularity of the particles of both components and the mixtures containing irregular particles segregated less on vibration.

Effects of tapioca obtained from cassava (Manihot utilissima) on the disintegration and dissolution rates of paracetamol tablets.

The properties of tapioca obtained from cassava (Manihot utilissima) have been evaluated. Its binding effect in tablets of paracetamol on the disintegration and dissolution rates was compared with tablets prepared with polyvinylpyrrolidone and gelatin. The nature and amount of the binders were found to alter the disintegration and dissolution rates of the tablets by reducing their wettability as measured by the adhesion tension of water. A linear relationship has been found to exist between the adhesion of water on the tablets and their disintegration and dissolution rates.

A consideration of the range and strength of interparticle forces in coated lactose powder.

A study has been made of the range and strength of interparticle forces in lactose powder coated with increasing concentrations of paraffins at different temperatures. Marked changes occurred in these forces as the paraffin content was altered and the temperature increased from -10 degrees to +50 degrees C. The strength and range of interparticle forces depended on the mechanical properties of the coating materials and the surface free energy of the coated powders.

The effect of the shape of fine particles on the formation of ordered mixtures.

A study has been made of the effects of the shape of fine particles on the formation and stability of some ordered mixtures using a specially constructed Y mixer. Irregular particles adhere to indentations on the surface of the carrier particles and form stable ordered mixtures.

The effects of interacting variables on the tensile strength, disintegration and dissolution of paracetamol tablets.

A factorially designed scheme has been used to analyse the separate and combined effects of packing fraction (P), nature of binder (N) and concentration of binder (C) on the tensile strength, disintegration and dissolution (t50%) times of paracetamol tablets. In general, P has the greatest effect on tensile strength, disintegration and dissolution times followed by C then N. For the variables in combination, the ranking of the effects on tensile strength, for the PVP/gelatin formulations, are P x N greater than N x C greater than P x C and for the PVP/tapioca formulations are P x C = N x C greater than P x N. For disintegration and for dissolution, the ranking for the PVP/gelatin formulations are P x C greater than P x N = N x C and P x N greater than P x C greater than N x C, respectively, and for the PVP/tapioca formulations are P x N greater than N x C = P x C. The results also show that tapioca acts as a binding agent when included in paracetamol tablet formulations, but it is a weaker binder than either PVP or gelatin. It is thus required in a higher concentration to produce tablets of comparable physical properties with those formulated with PVP or gelatin.

The packing characteristics of physical and formulated mixtures of oxytetracycline and lactose powders.

Measurements have been made of the tap densities and angles of internal flow of physically mixed and formulated mixtures of oxytetracycline and lactose powders. The differences between the two types of mixtures are ascribed to differences in the packing and surface morphologies of the particles.

Fundamental properties of metronidazole formulations in relation to tableting.

A study has been made of the effects of polyvinylpyrrolidone, gelatin and methylcellulose binding agents on the fundamental and tableting properties of a metronidazole-lactose-starch formulation. A material constant, alpha, was derived from the measured values of tensile strength of the materials. The values of alpha for the formulations are lower than that for metronidazole and depend on the nature and concentration of binder present. In terms of tableting properties, alpha supplements the information obtained from the ratios of elastic recovery to plastic compression (ER/PC) and from the brittle fracture index values (BFI) of the materials, although its influence appears to be limited at low values of ER/PC.

Dissolution mechanism of tablets produced from coated lactose powder.

The use of the equation of Kitazawa et al in the analysis of the dissolution process of tablets produced from lactose powder coated with paraffin has suggested either an initial breaking of the tablets into particles that subsequently break down into smaller particles or a progressive breaking of the tablet into smaller particles. The former produces a change in rate constant from k1 to k2.

Effects of applied load and particle size on the plastoelasticity and tablet strength of some directly compressible powders.

Correlations have been established between the particle size and packing fraction of microcrystalline cellulose, calcium phosphate dihydrate, corn starch and lactose, and the elastic recovery, stress relaxation, and tensile strengths of their tablets.

The effect of temperature on the plasto-elasticity of some pharmaceutical powders and on the tensile strengths of their tablets.

Measurements have been made of the stress relaxation (SR) during, and of the elastic recovery (ER) after, compression of four directly compressible excipients, and of chloroquine diphosphate and of a paracetamol tablet formulation at temperatures between -10 and +65 degrees C and of the tensile strengths of the tablets produced. It was found that at a fixed packing fraction, the stress relaxation and tensile strength of all the materials increased and the ratio ER/SR decreased as the compression temperature was raised. Tensile strength was inversely proportional to ER/SR at all the temperatures studied. Values for the activation energies (Eo) of bonding between particles for all the materials were derived from plots of the log of tensile strength and of log SR/ER versus the reciprocal of the absolute temperature. The values of Eo obtained from the latter plots tended to be higher than from the former by a factor of between 1.5 and 4.5.

Studies on metronidazole tablet formulations.

Incorporating polyvinylpyrrolidone, gelatin and methylcellulose binding agents in a metronidazole formulation alters the tensile strength, disintegration and dissolution times of the tablets by reducing their wettability as measured by the adhesion tension of water. Correlations have been established between the disintegration times, D and the dissolution times t50, t90 and t1 (derived from the equation of Noyes & Whitney). A correlation has also been established between the adhesion tension of water on the tablets and the disintegration and dissolution times. These correlations depend on the nature and concentration of binder used.

The plasto-elasticity and compressibility of coated powders and the tensile strengths of their tablets.

A study has been made of the effects produced on the tensile strength, brittle fracture index (BFI), 'plasto-elasticity' ratio, ER/PC, and yield pressure (1/KH derived from Heckel plots) of sodium salicylate and calcium carbonate as a result of coating their particles with increasing amounts of silicones and polysorbates before subjecting them to compression to form tablets. The coatings act as lubricants reducing bond formation due to plastic deformation of particles. They caused a reduction in the tensile strengths and yield pressures of the tablets but increased their BFI values and their ER/PC ratios. Tablets of calcium carbonate tended to cap or laminate when their BFI value was greater than 0.7 and their ER/PC ratio was greater than 7. Sodium salicylate whose BFI values were all less than 0.7 produced satisfactory tablets when their ER/PC ratio was less than 10 but tended to cap or laminate when it was greater than 10.

Effects of interacting variables on the tensile strengths and disintegration times of paracetamol tablets.

The effects of separately varying the packing fraction (P), the proportions of microcrystalline cellulose, Avicel (A) and alginic acid, disintegrant (D), on both the tensile strengths and disintegration times of paracetamol tablets are in the order P much greater than A much greater than D. The combined effects of these variables on both tensile strength and disintegration time are A X P much greater than D X P greater than A X D.

Effects of composition, moisture and stearic acid on the plasto-elasticity and tableting of paracetamol-microcrystalline cellulose mixtures.

Measurements were made under various conditions of the stress relaxation (SR) and elastic recovery (ER) of mixtures of paracetamol and microcrystalline cellulose (Avicel) and of the tensile strengths (T) of their tablets. T was inversely proportional to ER/SR. Tablets laminated or capped when they contained less than 25% w/w of cellulose and the value of ER/SR measured at 20 kN over a compression/decompression/ejection cycle of 2 min, was greater than 9. Addition of between 2 and 4% w/w of water increased the tensile strengths of tablets, provided they contained less than 75% w/w of cellulose, but more water caused decreases in T. Additions of up to 10% w/w stearic acid also caused decreases in T. Explanations are provided for the results.

Tensile strengths of paracetamol and Avicel powders and their mixtures.

Measurements were made of the tensile strengths of paracetamol and Avicel powders and of their mixtures. Two quantities were derived from the results; m, a universal constant whose value was 1.00 +/- 0.23 and alpha, a constant of the material. The value of alpha for paracetamol was much larger than that for Avicel and increased slightly with increase in particle size. Adding 25% w/w of Avicel to paracetamol produced a significant decrease in alpha and this fact may account for its use as an excipient in the tableting of paracetamol.

Simple, rapid method for comparing the self-emulsifiability of hydrocarbon oils.

A simple and rapid method for comparing the degree of self-emulsifiability of different hydrocarbon oils is described. The method involved measurement of the intensity of light scattered at an angle of 31 degrees to the incident radiation by the sample. The extent or degree of self-emulsification of selected hydrocarbon oils was observed to be affected by the nature of the oil as well as by the type and concentration of the surfactants employed. The method is useful when screening surfactant-hydrocarbon oil combinations as potential vehicles for drugs in the pharmaceutical industry or herbicides and pesticides for agricultural purposes.