Do pediatric medicines induce topographic changes in dental enamel?

Abstract The purpose of the present study was to evaluate the effect of common pediatric liquid medicines on surface roughness and tooth structure loss and to evaluate the pH values of these medicines at room and cold temperatures in vitro. Eighty-four bovine enamel blocks were divided into seven groups (n = 12): G1-Alivium®, G2-Novalgina®, G3-Betamox®, G4-Clavulin®, G5-Claritin®, G6-Polaramine® and G7-Milli-Q water (negative control). The pH was determined and the samples were immersed in each treatment 3x/day for 5 min. 3D non-contact profilometry was used to determine surface roughness (linear Ra, volumetric Sa) and the Gap formed between treated and control areas in each block. Scanning electron microscopy (SEM) and energy dispersive spectrometry (EDS) were also performed. The majority of liquid medicines had pH ≤ 5.50. G1, G4, and G5 showed alterations in Ra when compared with G7 (p < 0.05). According to Sa and Gap results, only G5 was different from G7 (p < 0.05). Alteration in surface was more evident in G5 SEM images. EDS revealed high concentrations of carbon, oxygen, phosphorus, and calcium in all tested groups. Despite the low pH values of all evaluated medicines, only Alivium®, Clavulin®, and Claritin® increased linear surface roughness, and only Claritin® demonstrated the in vitro capacity to produce significant tooth structure loss.

Effect of histamine H1 and H2 receptor antagonists, microinjected into cerebellar vermis, on emotional memory consolidation in mice

This study investigated the effects of histamine H1 or H2 receptor antagonists on emotional memory consolidation in mice submitted to the elevated plus maze (EPM). The cerebellar vermis of male mice (Swiss albino) was implanted using a cannula guide. Three days after recovery, behavioral tests were performed in the EPM on 2 consecutive days (T1 and T2). Immediately after exposure to the EPM (T1), animals received a microinjection of saline (SAL) or the H1 antagonist chlorpheniramine (CPA; 0.016, 0.052, or 0.16 nmol/0.1 µL) in Experiment 1, and SAL or the H2 antagonist ranitidine (RA; 0.57, 2.85, or 5.7 nmol/0.1 µL) in Experiment 2. Twenty-four hours later, mice were reexposed to the EPM (T2) under the same experimental conditions but they did not receive any injection. Data were analyzed using one-way ANOVA and the Duncan test. In Experiment 1, mice microinjected with SAL and with CPA entered the open arms less often (%OAE) and spent less time in the open arms (%OAT) in T2, and there was no difference among groups. The results of Experiment 2 demonstrated that the values of %OAE and %OAT in T2 were lower compared to T1 for the groups that were microinjected with SAL and 2.85 nmol/0.1 µL RA. However, when animals were microinjected with 5.7 nmol/0.1 µL RA, they did not show a reduction in %OAE and %OAT. These results demonstrate that CPA did not affect behavior at the doses used in this study, while 5.7 nmol/0.1 µL RA induced impairment of memory consolidation in the EPM.

H1 but not H2 histamine antagonist receptors mediate anxiety-related behaviors and emotional memory deficit in mice subjected to elevated plus-maze testing

This study investigated the role of H1 and H2 receptors in anxiety and the retrieval of emotional memory using a Trial 1/Trial 2 (T1/T2) protocol in an elevated plus-maze (EPM). Tests were performed on 2 consecutive days, designated T1 and T2. Before T1, the mice received intraperitoneal injections of saline (SAL), 20 mg/kg zolantidine (ZOL, an H2 receptor antagonist), or 8.0 or 16 mg/kg chlorpheniramine (CPA, an H1 receptor antagonist). After 40 min, they were subjected to the EPM test. In T2 (24 h later), each group was subdivided into two additional groups, and the animals from each group were re-injected with SAL or one of the drugs. In T1, the Student t-test showed no difference between the SAL and ZOL or 8 mg/kg CPA groups with respect to the percentages of open arm entries (%OAE) and open arm time (%OAT). However, administration of CPA at the highest dose of 16 mg/kg decreased %OAE and %OAT, but not locomotor activity, indicating anxiogenic-like behavior. Emotional memory, as revealed by a reduction in open arm exploration between the two trials, was observed in all experimental groups, indicating that ZOL and 8 mg/kg CPA did not affect emotional memory, whereas CPA at the highest dose affected acquisition and consolidation, but not retrieval of memory. Taken together, these results suggest that H1 receptor, but not H2, is implicated in anxiety-like behavior and in emotional memory acquisition and consolidation deficits in mice subjected to EPM testing.

Formulation development of chlorpheniramine maleate tablet by direct compression

Direct compression has continued to grow in pharmaceutical industries, since it cuts down the laborious events, faced in wet or dry granulation. The study aims at developing a new tablet formulation of chlorpheniramine maleate [4mg], using microcrystalline cellulose [Avicel PH 102], lactose DC, starch, tale, and magnesium stearate by direct compression. Different pharmacopoeial and non-pharmacopoeial tests were conducted to evaluate the characteristics of tablets. The new directly compressible tablets met the official standards and showed a percent drug release of 94.95 within 45 minutes and the assay was 100.66%. Results were compared with three commercially marketed tablet brands of chlorpheniramine maleate. Tablets were blister packed, and stability studies were carried out at room temperature and accelerated stability conditions. The analysis of stability was in accordance with the official limits, showing no substantial change during storage period. The physico-chemical data reveal that low dose drugs could be developed by a direct compression technique using suitable directly compressible excipients since it is a simplest, time saving and cost effective method of manufacturing

Chlorpheniramine impairs functional recovery in Carassius auratus after telencephalic ablation

We determined the effect of an H1 receptor antagonist on the functional recovery of Carassius auratus submitted to telencephalic ablation. Five days after surgery the fish underwent a spatial-choice learning paradigm test. The fish, weighing 6-12 g, were divided into four groups: telencephalic ablation (A) or sham lesion (S) and saline (SAL) or chlorpheniramine (CPA, ip, 16 mg/kg). For eight consecutive days each animal was trained individually in sessions separated by 24 h (alternate days). Training trials (T1-T8) consisted of finding the food in one of the feeders, which were randomly blocked for each subject. Animals received an intraperitoneal injection of SAL or CPA 10 min after the training trials. The time spent by the animals in each group to find the food (latency) was analyzed separately at T1 and T8 by the Kruskal-Wallis test, followed by the Student Newman-Keuls test. At T1 the latencies (mean ± SEM) of the A-SAL (586.3 ± 13.6) and A-CPA (600 ± 0) groups were significantly longer than those of the S-SAL (226.14 ± 61.15) and S-CPA (356.33 ± 68.8) groups. At T8, the latencies of the A-CPA group (510.11 ± 62.2) remained higher than those of the other groups, all of which showed significantly shorter latencies (A-SAL = 301.91 ± 78.32; S-CPA = 191.58 ± 73.03; S-SAL = 90.28 ± 41) compared with T1. These results support evidence that training can lead to functional recovery of spatial-choice learning in telencephalonless fish and also that the antagonist of the H1 receptor impairs it.

Chlorpheniramine facilitates inhibitory avoidance in teleosts submitted to telencephalic ablation

The present study investigated the involvement of H(1) histaminegic receptor on the acquisition of inhibitory avoidance in Carassius auratus submitted to telencephalic ablation. The fish were submitted to telencephalic ablation 5 days before the experiment. The inhibitory avoidance procedure included 1 day for habituation, 3 days for training composed of 3 trials each (1st day: T1, T2, T3; 2nd day: 2T1, 2T2, 2T3; 3rd day: 3T1, 3T2, 3T3) and 1 day for test. On training days, the fish were placed in a white compartment, after 30 s the door was opened. When the fish crossed to a black compartment, a weight was dropped (aversive stimuli). Immediately after the third trial, on training days, the fish received, intraperitoneally, one of the pharmacological treatments (saline (N = 20), 8 (N = 12) or 16 (N = 13) µg/g chlorpheniramine, CPA). On the test day, the time to cross to the black compartment was determined. The latency of the saline group increased significantly only on the 3rd trial of the 2nd training day (mean ± SEM, T1 (50.40 ± 11.69), 2T3 (226.05 ± 25.01); ANOVA: P = 0.0249, Dunn test: P < 0.05). The group that received 8 µg/g CPA showed increased latencies from the 2nd training day until the test day (T1 (53.08 ± 17.17), 2T2 (197.75 ± 35.02), test (220.08 ± 30.98); ANOVA: P = 0.0022, Dunn test: P < 0.05)). These results indicate that CPA had a facilitating effect on memory. We suggest that the fish submitted to telencephalic ablation were able to learn due to the local circuits of the mesencephalon and/or diencephalon and that CPA interferes in these circuits, probably due an anxiolytic-like effect.

Chlorpheniramine impairs spatial choice learning in telencephalon-ablated fish

This work investigated the effect of the Hj receptor blockade in the forebrain of ablated Carassius auratus in a simple stimulus-response learning task using a T-maze test with positive reinforcement. The goldfish were submitted to surgery for removal of both telencephalic lobes five days before beginning the experiment. A T-shaped glass aquarium was employed, with two feeders located at the extremities of the long arm. One of the two feeders was blocked. The experimental triáis were performed in nine consecutive days. Each fish was individually placed in the short arm and confined there for thirty seconds, then it was allowed to swim through the aquarium to search for food for ten minutes (máximum period). Time to find food was analysed in seconds. Animáis were injected intraperitoneally with chlorpheniramine (CPA) at 16 mg/kg of body weight or saline after every trial, ten minutes after being placed back in the home aquarium. The results show that all the training latencies of the A-SAL group were higher than the latencies of the S-SAL group. The S-SAL group had decreased latencies from the second trial on, while the S-CPA group showed decreased latencies after the fourth trial. The A-SAL group showed reduced latencies after the fifth trial, but the A-CPA group mainteined the latencies throughout the experiment. This suggests that CPA impairs the consolidation of learning both on telencephalon ablated animáis and in sham-operated ones through its action on mesencephalic structures of the brain and/or on the cerebellum in teleost fish.

evaluate and compare the effects of first generation anti-histamine [chlorpheniramine maleate] and second generation anti-histamine [Cetirizine dihydrochloride] on isolated trachea of rabbit

Histamine is generally considered as the principal mediator of the acute inflammatory process and the allergic and anaphylactic reaction in both the upper and lower respiratory airways. Chlorpheniramine maleate is a stable, most potent, .first generation antihistamine. It is clinical efficacy in the treatment of IgE mediated histamine disorders is well established. Cetirizine dihydrochloride is a potent, non-sedative HI receptor antagonist, belongs to second generation antihistamines. It is highly effective and safe drug for treating seasonal and perennial allergic rhinitis amid urticaria. Also used in chronic idiopathic urticaria and atopic dermatitis. The purpose of study was to evaluate the antagonostic effects of chlorpheniramine maleate and cetirizine dihydrochloride on histamine induced contractions in isolated trachea of rabbit and to compare the effects of first generation anti-histamine [chlorpheniramine maleate] and second generation anti-histamin [cetirizine dihydrochloride] on isolated trachea of rabbit. In this study twenty-four experiments were performed on isolated trachea of rabbit, in the presence of selected standard concentration of histamine dihydrochloride antagonistic effects of various concentrations of chlorpheniramine male-ate [10e-18 to 10e-3 gm/ml] and cetirizine dihydrochloride from concentrations to 10-3 gml ml were recorded by Polygraph Model 7B in terms of rate and amplitude. Chlorphenimmine maleate showed non-significant antagonistic effect from concentrations 10e-18 to 10e-9 gm/ml in case of rate and 10e-18 to 10e-8 gm/ml in case of amplitude. Significant response showed from concentrations 10e-8 to 10e-3 gm/ml in care of rate [P<0.001] and 10e-7 to 10e-3, gm/ml in case of amplitude [P<0.001] while, cetirizine showed non-significant response front concentrations to, gm/ml in case of rate and 10e-18 to 10e-12 gm/ml in case of amplitude. Significant response observed from concentrations 10e-12 to 10e-3 gm/ml in case of rate [P<0.001] and 10e-11 to 10e-3 gm/ml in case of amplitude [P<0.001]. It was concluded that chlorpheniramine maleate antagonized thetukl tisatnmd mine induced contractions 80.65% at concentration la, gm/ml in case of amplitude 11.35% at concentration 10e-3 gm/ml in case of rate and cetirizine dihydrochloride 82.69% in case of amplitude and 12.33% in case of rate

Influence of histamine and H1-receptor antagonists on ejaculated human spermatozoa: role of intrasperm Ca2+.

Histamine reduced sperm viability in a dose- and time-dependent manner, accompanied by rise in intrasperm Ca2+. Further, 2',4'-dichlorobenzamil hydrochloride (DBZ), a Na+-Ca2+ exchange inhibitor, known to elevate intrasperm Ca2+, potentiated both, elevation of intrasperm Ca2+ and spermicidal action of histamine. Pretreatment of sperm with very low doses of H1-receptor antagonists (chlorpheniramine, promethazine or diphenhydramine) prevented the histamine-induced elevation of intrasperm Ca2+ as well as its spermicidal action. However, pretreatment with famotidine, a H2-receptor antagonist did not produce such a protective action. The results strongly suggest that histamine elicits its spermicidal action via H1-receptors present on sperm cells.

Compuestos lisosomotrópicos inhibidores de la multiplicación del virus Junín / Lysosomotropic compounds inhibiting the multiplication of Junin virus

La multiplicación del virus Junín en células Vero fue inhibida por la acción de drogas lisosomotrópicas de carácter básico como cloruro de amonio, clorhidrato de procaína y clorofeniramina. El efecto inhibitorio del cloruro de amonio (15mM) es máximo cuando la droga es agregada junto con el inóculo viral o inmediatamente después de la infección, pero aun agregado 8 horas después de la infección produce una inhibición significativa del 97,8%. Estos resultados indicarían que la droga actúa fundamentalmente sobre una etapa temprana del ciclo de multiplicación viral. Por lo tanto, el mecanismo de entrada del virus Junín a la célula transcurriría a través de una endocitosis mediada por receptor

Studies on morphine analgesia.

Several agents with specific action on biologically active substances in brain were investigated for their influence on morphine analgesia. It was observed that imipramine, chlorpheniramine, and haloperidol antagonized morphine analgesia. The probable mechanism of action has been discussed.

On the Degranulation of Mesenteric Mast Cells Caused by Antihistamine in Albino Rats: Effects of Various Dosages of Antihistamine

Degranulation of the mast cell has been reported by the injection of histamine liberators and other chemical agents. Chlorpheniramine maleate (1.2mg./kg. and 0.3mg./kg. comprising 1/74and 1/290 of LD50 respectively), which is an antihistamine agent, in physiological saline solution for intravenous injection and in Tyrode solution for intraperitoneal injection were given in single dose. The mesenteric mast cells stained in Pugh solution, as applied by Lee (1968), were counted according to the classification of An (1964) in 4 types; the typical normal mast cell, the Grade I type of mast cell, the Grade II type of mast cell and the Grade III type of mast cell. In the experimental rats given 1.2mg./kg. of chlorpheniramine intravenously, more mesenteric mast cells were s1ightly degranulated than those cells of the rats given 0.3mg./kg. of chlorpheniramine and the control rats. In the experimental rats given 1.2mg./kg. and 0.3 mg./kg. of chlorpheniramine intraperitoneally, more mesenteric mast cells were slightly degranulated than those cells of the control rats. However, in this intraperitoneal study the degree, or severity, of degranulation of the mesenteric mast cell was not in direct proportion to the dosage of this antihistamine. Consequently it is deduced that the experimental dosage of the antihistamine chlorpheniramine maleate, applied 1/74 and l/290 of LD50, caused an evient degranulation of mesenteric mast cells of the albino rats associated with probable histamine liberation.