Investigation of melt agglomeration process with a hydrophobic binder in combination with sucrose stearate

The melt agglomeration process of lactose powder with hydrogenated cottonseed oil (HCO) as the hydrophobic meltable binder was investigated by studying the physicochemical properties of molten HCO modified by sucrose stearates S170, S770 and S1570. The size, size distribution, micromeritic and adhesion properties of agglomerates as well as surface tension, contact angle, viscosity and specific volume of molten HCO, with and without sucrose stearates, were examined. The viscosity, specific volume and surface tension of molten HCO were found to be modified to varying extents by sucrose stearates which are available in different HLB values and melt properties. The growth of melt agglomerates was promoted predominantly by an increase in viscosity, an increase in specific volume or a decrease in surface tension of the molten binding liquid. The agglomerate growth propensity was higher with an increase in inter-particulate binding strength, agglomerate surface wetness and extent of agglomerate consolidation which enhanced the liquid migration from agglomerate core to periphery leading to an increased surface plasticity for coalescence. The inclusion of high concentrations of completely meltable sucrose stearate S170 greatly induced the growth of agglomerates through increased specific volume and viscosity of the molten binding liquid. On the other hand, the inclusion of incompletely meltable sucrose stearates S770 and S1570 promoted the agglomeration mainly via the reduction in surface tension of the molten binding liquid with declining agglomerate growth propensity at high sucrose stearate concentrations. In addition to being an agglomeration modifier, sucrose stearate demonstrated anti-adherent property in melt agglomeration process. The properties of molten HCO and melt agglomerates were dependent on the type and concentration of sucrose stearate added.     

Ethanol regulated preference in rats

A series of experiments evaluated the determinants of preference for mixtures of ethanol plus sucrose relative to sucrose in rats. One dipper served 10% ethanol mixed with 10% sucrose, and the second dipper served 10% sucrose. Lever presses operated each dipper according to a variable-interval 5-s schedule. In three experiments the subjects were given pre-session meals of sucrose (2.5–20 ml) or sucrose (20 ml) plus chow (5 or 10 g). Pre-session meals decreased responding maintained by sucrose but not responding maintained by ethanol mixture. In two experiments body weight was varied from 85% to 125% of the initial free-feeding values. Increases in body weight, like pre-session meals, decreased responding reinforced by sucrose, but typically did not decrease responding reinforced by ethanol mixture. Throughout most of the study, ethanol consumption remained at about 1.25 ml per half hour session (3–4 g/kg per 30 min). For example, pre-session access to ethanol mixture decreased within-session ethanol consumption, but total consumption, counting both sources, remained about 1.25 ml/session. The within-session patterns of responding also differed. Responding reinforced by ethanol mix decreased as a function of ethanol consumption, whereas responding reinforced by sucrose was relatively constant throughout the session. The simplest explanation of the results is that ethanol's pharmacological consequences regulated preference.     

Naloxone administration following operant training of sucrose/water discrimination in the rat

 The suppression of food intake observed following naloxone administration has often been ascribed to palatability or taste. Unfortunately, many confounds become apparent when attempts are made to isolate such factors in the investigation of ingestive behaviors. In the present study, rats (two groups) were trained to discriminate either a 10% or 5% sucrose solution from water (0.1 ml). These mildly food deprived subjects (95% of free-feeding weight) were trained to press the appropriate lever in a two-lever operant chamber following sampling of sucrose or water; successful responding was reinforced by delivery of a 45 mg grain food pellet. Following random exposure to reduced sucrose concentrations tested under extinction, a sucrose concentration gradient (1.0, 0.5, 0.1, 0.05, 0.01 and 0.005% sucrose solution) was established for both training groups under IP saline administration. Data collected under IP saline were then compared to those collected following random IP naloxone administration (3.0, 1.0, 0.3 and 0.1 mg/kg). No significant differences were observed between the sucrose concentration gradients obtained under saline and those obtained under naloxone, suggesting that the anorectic effect of naloxone is not primarily determined by discrimination of sweet taste. Received: 4 September 1996 / Final version: 16 October 1996     

Reversal of stress-induced anhedonia by the dopamine receptor agonist,pramipexole

Chronic exposure to mild unpredictable stress has previously been found to depress the consumption of a palatable (1%) sucrose solution, and to attenuate food-induced place preference conditioning. In this study the effects of pramipexole (SND-919), a dopamine D₂ agonist, were studied during 7–9 weeks of chronic treatment. Pramipexole (1.0 mg/kg per day) reversed the suppression of sucrose intake in stressed animals, increasing sucrose intakes above the levels seen in untreated nonstressed controls. Pramipexole also increased sucrose intake in nonstressed animals; these effects were accompanied by increases in water intake and tended to correlate with weight loss. Drug-treated stressed animals also lost weight, but in this case water intake was unaffected. A second group of animals received a higher dose of pramipexole (2.0 mg/kg per day). The effects of the two doses were very similar. After three weeks of treatment, these animals were switched to a lower dose of pramipexole (0.1 mg/kg per day). Increases in sucrose intake were maintained over three weeks of treatment at the lower dose, with significant recovery of body weight. Two further groups received the same doses of pramipexole (1.0 mg/kg for 6 weeks or 2.0 mg/kg for 3 weeks followed by 0.1 mg/kg thereafter), but received intermittent (twice-weekly) drug treatment. Intermittent pramipexole treatments also tended to increase sucrose intakes, but the results were less consistent from week to week. Following 6–8 weeks of pramipexole treatment, food-induced place preference conditioning was studied in all animals. Untreated stressed animals showed no evidence of place conditioning. Normal conditioning was seen in both groups of stressed animals treated daily with pramipexole (at 1.0 and 0.1 mg/kg) and in the group treated twice weekly at the higher dose (1.0 mg/kg); intermittent treatment at the lower dose (0.1 mg/kg) was ineffective. The results indicate that pramipexole exerts rapid anti-anhedonic effects in the chronic mild stress model. This conclusion is complicated, but not undermined, by drug-induced weight loss and by the presence of significant drug effects in nonstressed control animals.     

Competition for sucrose-pellets in triads of male wistar rats: effects of acute and subchronic chloridazepoxide

Within triads of male Wistar rats, some animals almost completely abstain from competition for palatable sucrose pellets (so-called poor-performing rats), whereas other rats consistently win the competition (so-called high-performing rats). Subchronic (5 mg/kg; 5 consecutive days), but not acute (0.1–20 mg/kg), treatment with chlordiazepoxide temporarily helped poor-performing rats to behave more competitively. This finding, considered together with parallel studies (using high-performing rats), suggested that chloridazepoxide's beneficial effect was only demonstrable when the poor-performing rats had become tolerant to the drug's initial sedative effect.     

Effet apaisant du sucre chez le nouveau-né: revue de la littérature

Résumé  Le saccharose, administré à une concentration d’au moins 12% chez le nouveau-né à terme (24% chez le prématuré), en petite quantité (0,05 à 2 ml), dans une seringue ou mieux dans une tétine, 2 minutes avant la réalisation d’un soin douloureux avec effraction cutanée (microprélèvement, ponction veineuse), permet de réduire, plus rarement d’abolir, les comportements de détresse et/ou de douleur (pleurs et manifestations faciales). Il s’agit d’un moyen simple, non médicamenteux, et utilisable partout, qui doit pouvoir représenter une aide non négligeable chez les nouveau-nés, pour la prise en charge de la douleur provoquée par des soins modérément douloreux. Il peut être utilisé seul, mais son action limitée rend préférable de l’envisager comme technique adjuvante. Son mode d’action reste encore peu clair, ainsi que sa tolérance en cas d’administrations pluri-quotidiennes.

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Summary  Sucrose of at least 12% concentration delivered to full-term infants (24% concentration for preterm infants), in a small volume of 0.05 to 2 ml, through a syringue or better through a pacifier, 2 minutes before blood sample such as heel-stick or venipuncture, can attenuate or hardly abolish stress and/ or pain (crying and facial expressions). It is a simple non pharmacological treatment, helpful in the management of pain related to moderate painful procedures. As it exerts moderate effects, it is better used as an adjuvant treatment than used alone. Mechanisms of effects are not clear yet, as well as the occurrence of adverse effects when repeated daily administrations.

     

Reinstatement of alcohol-seeking by priming injections of alcohol and exposure to stress in rats

 Previous studies using a reinstatement procedure have found that acute reexposure to the self-administered drug and exposure to footshock stress reinstate heroin and cocaine seeking after prolonged drug-free periods. Here we tested whether these findings generalize to alcohol-taking behavior. Male rats were initially allowed to consume alcohol in a two-bottle choice procedure (water versus alcohol) for 30 min/day for 36 days. Rats were then trained for 60 min/day in operant chambers to press a lever for the drug (0.13 ml of 12% w/v of an alcohol solution) for up to 55 days. After stable drug-taking on a fixed-ratio-3 schedule of reinforcement was obtained, lever pressing for alcohol was extinguished by terminating drug delivery for 4–9 days. Reinstatement of drug seeking was then determined after non-contingent priming injections of alcohol (0.24 and 0.48 g/kg; given IP and orally) or exposure to intermittent footshock stress (5 and 15 min; 0.8 mA). Priming injections of alcohol produced a modest dose-dependent reinstatement of drug seeking, whereas footshock stress potently reinstated extinguished alcohol seeking. In contrast, similar parameters of footshock failed to reinstate extinguished sucrose-taking behavior in rats previously trained to lever press for sucrose pellets. These findings extend previous reports on reinstatement of cocaine and heroin seeking by a footshock stressor and by priming drug injections. It also appears that the reinstatement procedure provides an appropriate methodology to study relapse to alcohol-taking behavior in the drug-free state. Received: 9 April 1997 / Final version: 1 August 1997     

Effect of limited access to sucrose on overeating and patterns of feeding

Four groups of adult rats, housed on a 12-12, light-dark cycle, were allowed access to a nutritionally complete diet and water. Three of these groups were also offered a 32% solution of sucrose. The sucrose was available for either the 24-hour period, the 12 hours of light or the 12 hours of dark. Access to sucrose led to overeating and excessive weight gain. These effects were more pronounced when the sucrose was available for the 24-hour period or during the dark. Limited access to sucrose produced a reversal of the rat's usual circadian pattern of feeding when the sucrose was available during the light and increased the rat's nocturnal hyperphagia when it was available during the dark. Sucrose intake and the proportion of calories taken from sucrose were higher in the 24-hour access group and the dark access group than the light access group. Access to sucrose did not induce a pattern of dietary selection that compromised growth or health. It appears that access to a palatable carbohydrate solution can lead to overeating and major changes in the circadian organization of feeding behavior. These data emphasize the potent role that external factors can play in the control of ingestive behavior.     

Secretory transmembrane potentials in acinar cells from the cat submandibular gland during perfusion with a chloride-free sucrose solution

Summary The cat submandibular gland was perfused with a normal NaCl Locke solution and a chloride-free sucrose solution. The numerical increase in acinar membrane potential (secretory potential) was recorded after intra-arterial injection of acetylcholine.There was no significant difference between the size of the secretory potentials recorded during perfusion with the sucrose solution [23.6 mV±1.4 (n=23)] and the size of those recorded during the control periods [20.6 mV±1.2 (n=24)].The maximal value of the membrane potential after injection of acetylcholine was higher [51.8 mV±2.4 (n=23)] during perfusion with the sucrose solution than during the control periods [44.8 mV±1.8 (n=22)].The results show that a pump transporting chloride into the acinar cells cannot be responsible for the generation of the secretory potentials. The results are best accounted for by assuming that an outward passive transport of potassium, being partly short-circuited by an inward passive sodium transport, is responsible for the change in membrane potential after stimulation with acetylcholine.Supported by the Danish State Research Foundation and Johann and Hanne Weimann's legate.