OBJECTIVE: Zinc, an essential trace element and a component of many enzymes, is involved in the synthesis, storage and release of insulin. The aim of the present study was to assess the effect of zinc supplementation on insulin resistance and components of the metabolic syndrome in prepubertal obese children. DESIGN: This triple-masked, randomized, placebocontrolled cross-over trial was conducted among 60 obese Iranian children in 2008. Pertinent clinical findings, fasting serum glucose, insulin and lipid profile were assessed. Participants were randomly assigned to two groups of equal number; one group received 20mg elemental zinc and the other group received placebo on a regular daily basis for eight weeks. After a 4-week wash-out period, the groups were crossed over. RESULTS: The mean age of participants was 9.1 ± 1.1 years. After receiving zinc, the mean fasting plasma glucose (FPG), insulin and HOMA-IR decreased significantly, while body mass index (BMI), waist circumference (WC), LDL-C and triglycerides (TG) did not significantly change. After receiving placebo, the mean FPG, insulin and HOMA-IR increased significantly, while BMI, WC, LDL-C and TG showed a non-significant increase. CONCLUSION: Besides lifestyle modification, zinc supplementation might be considered as a useful and safe additional intervention treatment for improvement of cardiometabolic risk factors related to childhood obesity.

These results are particularly important in light of the deleterious consequences of childhood obesity and early changes in markers of inflammatory and oxidative stress. We suggest exploring the direct clinical application of zinc supplementation in childhood obesity in future studies.

The objective of this work was to develop matrix sustainedrelease tablets of highly water-soluble tramadol HCl using natural gums (xanthan [X gum] and guar [G gum]) as costeffective, nontoxic, easily available, and suitable hydrophilic matrix systems compared with the extensively investigated hydrophilic matrices (ie, hydroxypropyl methylcellulose [HPMC]/carboxymethyl cellulose [CMC] with respect to in vitro drug release rate) and hydration rate of the polymers. Matrix tablets of tramadol (dose 100 mg) were produced by direct compression method. Different ratios of 100:0, 80:20, 60:40, 20:80, 0:100 of G gum (or X):HPMC, X gum:G gum, and triple mixture of these polymers (G gum, X gum, HPMC) were applied. After evaluation of physical characteristics of tablets, the dissolution test was performed in the phosphate buffer media (pH 7.4) up to 8 hours. Tablets with only X had the highest mean dissolution time (MDT), the least dissolution efficiency (DE 8 %), and released the drug following a zero-order model via swelling, diffusion, and erosion mechanisms. Guar gum alone could not efficiently control the drug release, while X and all combinations of natural gums with HPMC could retard tramadol HCl release. However, according to the similarity factor ( f 2 ), pure HPMC and H 8 G 2 were the most similar formulations to Topalgic-LP as the reference standard.

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Metoprolol tartrate sustained-release tablets (100 mg) were prepared using xanthan/guar gums and also hydroxypropyl methyl cellulose (HPMC) carboxymethyl-Cellulose (CMC) polymers by direct compression method. Physical characteristics of the tablets and water uptake in addition to their dissolution profiles were compared with standard (Lopressor SR) tablets. Dissolution test was performed in the phosphate buffer solution (pH 6.8) and the samples were analyzed spectrophotometerically in 275.7 nm. Dissolution studies showed that formulations containing 100 and 80% of HPMC, 100% of guar, and 20% of xanthan followed the Higuchi model, while those containing 60 and 40% HPMC and 100 and 80% xanthan followed a zero-order model. The tablets with 40% xanthen followed a Hixon-Crowell model. In cellulose derivatives the highest MDT and dissolution efficiency until 8 hr (DE8%) belonged to tablets with 40% HPMC, increasing the amount of CMC decreased the drug release rate, and formulations containing 60 and 40% of HPMC had the USP dissolution standards. While, in the gum formulations, the highest mean dissolution time and the lowest DE(8)% belonged to tablets with 100% xanthan, increasing the xanthan decreased the release rate of metoprolol, and formulations containing 80 and 100% xanthan had the USP dissolution standards. Results showed that natural gums are suitable for production of sustained-release tablets of metoprolol.

Ciprofloxacin is mainly absorbed in the proximal areas of the gastrointestinal tract. The purpose of our study was production of floating-bioadhesive tablets to lengthen the stay of drug in its absorption area. Effervescent tablets were made using sodium carboxymethyl cellulose (CMC), hydroxypropyl methylcellulose (HPMC), polyacrylic acid (AA), polymetacrylic acid (MAA), citric acid, and sodium bicarbonate. Tablets with 5% effervescent base had longer lag time than 10%. The type of polymer had no significant effect on the floating lag time. All tablets floated atop the medium for 23-24 hr. Increasing CMC caused higher mucoadhesion than AA (p < 0.05). All formulations showed a Higuchi, non-Fickian release mechanism. Tablets with 10% effervescent base, 80% CMC/20% HPMC, or 80% AA /20% MAA seemed desirable.

A limited period of such treatment may help weight control, and might be used to encourage those children who have been refractory to weight loss for continuing the non-pharmacological programs. Our findings should be confirmed in future studies with a longer follow-up period.

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