Anionic Gels as Vehicles for Electrically-Modulated Drug Delivery. I. Solvent and Drug Transport Phenomena

Purpose. The purpose of this study was to elucidate the in vitro behavior of anionic gels as formulation matrices for electrically-modulated drug delivery. Agarose and combinations of agarose with other anionic polymers (carbomer 934P; xanthan gum) were selected and tested to evaluate their potential for drug delivery. Methods. Electrical current was applied by an automatic crossover power supply to minimize the current fluctuation. Hydrocortisone was selected as the model drug in order to minimize electrostatic interference with drug transport. Syneresis and drug migration were evaluated as a function of current application time and the intensity of electrical current. Results. The data show that electrical current strength and gellant content can affect both the syneresis and drug migration. A linear correlation was found between hydrocortisone loss and mass loss via the exudate. Moreover, in agarose-carbomer 934P gel systems, cumulative gel mass loss is a linear function of time at low intensities of electrical current (e.g., 0.5 mA and 1 mA). However, hydrocortisone distribution, after electrical application, is relatively asymmetric in those agarose-carbomer 934P gels (and in agarose-xanthan gum gels) in contrast to gel matrices containing only agarose. Conclusions. In this study, the use of carbomer 934P in conjunction with agarose enables the formulator to achieve zero-order release with electrical application. Increased anisotropicity of a gel system due to the application of electrical current could alter the effectiveness of a drug delivery system.     

Hypocholesterolemic effect of gum acacia in men

Fifteen grams of gum acacia administered twice daily to seven hypocholesterolemic subjects for 30 days, reduced their serum cholesterol by approximately 10.4% but had little effect on HDL cholesterol and triglycerides, LDL+VLDL cholesterol was decreased significantly (p<0.05).     

The maternal-foetal distribution of thiabendazole administered in two different vehicles to pregnant mice

We have compared the effects of two vehicles on the maternal-foetal distribution of 14C-thiabendazole ([14C]TBZ) given orally to Jcl: ICR mice on day 9 or 16 of gestation. TBZ, either suspended in olive oil (TBZ-O) or in a 0.5% aqueous solution of gum arabic (TBZ-G), was given orally on day 9 of gestation at a dose of 1 g/kg body weight (1 microCi/mouse). The mice were killed 0.5, 1, 3, 6, 12, 24 or 72 hr later. In mice treated with TBZ-O maximum levels of radioactivity in plasma and conceptuses were observed at 0.5 hr, whereas in those treated with TBZ-G maximum 14C levels were observed at 6 hr. The uptake of radioactivity from TBZ-O into the plasma and conceptuses was significantly higher than that from TBZ-G. Only trace levels of radioactivity were detected at 72 hr in both treatment groups. The placental transfer of [14C]TBZ was examined in mice treated with doses of 1 g/kg body weight (1 microCi/mouse) given as TBZ-O or TBZ-G on day 16 of gestation. The radioactivity in foetuses, placentas and maternal plasma was higher in mice treated with TBZ-O than those given TBZ-G. The placental transfer of [14C]TBZ was also examined by whole-body autoradiography in mice treated on day 16 of gestation.     

The effects of dietary gum tragacanth in man

Following a 7-day control period, 5 male volunteers consumed 9.9 g gum tragacanth (GT) daily for 21 days. The GT was well tolerated and there were no adverse effects in any of the volunteers. The daily intake was very high in relation to the minor amounts of GT (estimated at 2 g per person per annum) likely to be ingested as a foodstuffs additive. The wide range of measurements made before and at the end of the test period show that the ingestion of GT had no significant effect on any of the following: plasma biochemistry; haematological indices; urinalysis parameters; glucose tolerance; serum cholesterol, triglycerides and phospholipids; breath hydrogen and methane concentrations. The intestinal transit time decreased and faecal fat concentration increased (P less than 0.01) for 4 subjects. The faecal wet and dry weights increased in all subjects (P less than 0.01). These changes may be of nutritional and physiological interest but do not reflect any adverse toxicological effects arising from the ingestion of large daily doses of GT.     

Molecular weight of Acacia

Studies on Acacia were carried out to evaluate its molecular weight and its polydispersity by using a fractional coacervation method. The characterization was done by tonometric and viscosimetric measurements. By the application of Mark-Houwink equation, the viscosity average weight of Acacia has been evaluated about 65,400. The theoretical treatment of the experimental data permits to show that the function of distribution of the molecular weights of this polymer follows a log-nor-mal law and the index of polydispersity of the studied sample is little dispersed.     

Dietary guar gum supplementation does not modify insulin resistance in gross obesity

Summary Obesity is considered an insulin resistant state. Dietary guar gum supplementation is able to reduce blood glucose and plasma insulin response to a carbohydrate meal. In order to evaluate whether guar is able to reduce hyperinsulinemia and insulin resistance in gross obesity, we studied 9 obese patients, >50% overweight with impaired glucose tolerance before and after 4+4 g/day guar for 6 weeks. Six patients repeated the treatment with 8+8 g/day guar after a 3-month interval. Guar was added to the usual diet in order to maintain the body weight constant. Pre-treatment and post treatment study included: total specific insulin binding on circulating monocytes; 3H-glucose infusion and euglycemic hyperinsulinemic clamp at ∼100 μU/ml. The differences between post-treatment and pre-treatment values were not significant for any of the parameters studied. Fasting glucose production was: 2.17±0.33 SEM (pretreatment)vs 2.18±0.18 (4+4 g/day)vs 2.28±0.14 (8+8 g/day) mg/kg/min; glucose utilization was: 3.52±0.43vs 3.22±0.44vs 3.49±0.63 mg/kg/min; total specific insulin binding was: 2.80±0.20vs 2.75±0.25vs 2.78±0.31%; body weight was: 101.4±5.4vs 100.2±6.2vs 100.5±7.0 kg. These results indicate that dietary guar gum supplementationper se is unable to reduce insulin resistance in gross obesity if overweight is maintained constant.     

Effect of sorbitol- and xylitol-containing chewing gum on salivary microflora, saliva, and oral sugar clearance

Abstract – The effect of frequent use of a sorbitol-containing nicotine chewing gum on saliva secretion rate and buffer capacity and some oral bacteria was studied in 27 patients at a smoking cessation clinic. The effect was compared with that obtained after frequent use of a chewing gum containing xylitol in a second study in 14 subjects. The results showed that sorbitol-containing nicotine chewing gum had no significant effect on salivary numbers of oral streptococci and lactobacilli during a 3-month period of active chewing five times a day. Chewing on xylitol-containing gum caused a significant decrease in salivary S. mutans after 2 months but not after 3 months. No change in secretion rate or buffer capacity was observed in the two studies. Oral sugar clearance time was reduced after 3 months with a statistically significant difference to baseline values in subjects consuming the sorbitol-containing nicotine chewing gum.     

阿拉伯胶对胰蛋白酶的化学修饰

用阿拉伯胶修饰胰蛋白酶。修饰酶的活性约为天然酶的62%,其热稳定性及抗胃蛋白酶消化力均大于天然酶。     

Artificial sweetener use among individuals with eating disorders

Women with eating disorders report using large quantities of artificially sweetened products, but this has not been quantified. OBJECTIVE: The authors assessed the use of selected artificially sweetened low-calorie products among women with eating disorders compared with controls. METHOD: Thirty women with anorexia nervosa (18 with the restricting subtype [AN-R] and 12 with the binge/purge subtype [AN-B/P]), 48 women with bulimia nervosa (BN), and 32 healthy control women completed a survey of frequency and amount of consumption of chewing gum, artificially sweetened low-calorie beverages, and packets of artificial sweetener in the previous month. RESULTS: A greater proportion of women with AN-B/P and BN reported use of each product, compared with women with AN-R and control participants. Among product users, patients with eating disorders reported using greater amounts than controls. Among patients who reported binge eating and/or purging, the quantity of each product used was inversely correlated with body mass index (BMI). CONCLUSION: These data suggest an increased drive for sweet orosensory stimulation in women with AN and BN.