盐酸恩丹西酮注射液与注射用卡铂配伍的稳定性考察

目的 :考察盐酸恩丹西酮注射液与注射用卡铂的配伍稳定性。方法 :采用紫外分光光度法测定盐酸恩丹西酮注射液与注射用卡铂配伍后在室温下8h内的含量变化 ,并观察外观及测定其 pH值的变化。结果 :配伍液外观、pH值及含量均无明显变化。结论 :盐酸恩丹西酮注射液与注射用卡铂在配伍后8h内稳定。     

盐酸恩丹西酮缓释胶囊的制备及质量控制

目的:制备盐酸恩丹西酮缓释胶囊并建立其质量控制方法。方法:制备盐酸恩丹西酮缓释胶囊;测定盐酸恩丹西酮释放度,进行释放机制及影响因素研究;用高效液相色谱法测定主药盐酸恩丹西酮的含量。结果:制得盐酸恩丹西酮胶囊体外释放曲线符合一级动力学方程和Higuchi方程;盐酸恩丹西酮检测浓度在9.93～79.44μg/ml范围内与峰面积积分值线性关系良好,平均回收率为100.15%(RSD=0.44%)。结论:该制剂具有明显的缓释作用,制备工艺简单,值得推广。     

RP-HPLC测定盐酸恩丹西酮注射液中盐酸恩丹西酮的含量

盐酸恩丹西酮(ondansetron hydrochloride)是一种高效并有高度选择性的5-羟色胺受体拮抗剂。临床上用于癌症药物化疗和放射性治疗引起的恶心呕吐。有文献用紫外分光光度法和高效毛细管区带电泳技术测定含量。未见用RP-HPLC法测定的报道，本文建立了用RP-HPLC法测定盐酸恩丹西酮注射液制剂中的盐酸恩丹西酮含量，经方法考察，本法简便、快速、准确、结果可靠，可用于本品质量控制和临床应用检测。     

盐酸恩丹西酮葡萄糖注射液稳定性研究

目的 :研究盐酸恩丹西酮葡萄糖注射液的稳定性。方法 :以高效液相色谱法测定盐酸恩丹西酮及其有关物质的含量 ,分别用强光照射法、加速试验法和室温留样观察法对盐酸恩丹西酮葡萄糖注射液进行稳定性试验。结果 :除强光照射条件下本品含量略有下降外 ,加速试验和室温留样观察各项指标均符合质量标准的规定。结论 :本品在避光、密闭的贮存条件下性质稳定 ,室温下贮存期可定为2年。     

盐酸恩丹西酮鼻用凝胶剂的制备与质量控制

目的设计盐酸恩丹西酮鼻用凝胶剂处方,并建立其质量控制方法.方法以卡波姆-940和甘油作为凝胶基质和主要辅料,用三乙醇胺调节pH值,制备盐酸恩丹西酮鼻用凝胶剂,采用紫外分光光度法对凝胶剂中盐酸恩丹西酮的含量进行测定.结果所得凝胶剂质量稳定,含量准确,盐酸恩丹西酮平均回收率为100.15%.结论该制剂制备工艺简便、稳定性好,质量控制方法简便、快速、准确.     

盐酸恩丹西酮口服液的制备及质量控制

目的研究盐酸恩丹西酮口服液的制备及质量控制方法,考察其稳定性并预测室温贮存有效期。方法确定了盐酸恩丹西酮口服液的处方,应用紫外分光光度法测定口服液中盐酸恩丹西酮的含量,用初均速法预测有效期。结果盐酸恩丹西酮口服液质量浓度在4.236～21.18μg/mL范围内与吸光度线性关系良好,低、中、高3种质量浓度样品的回收率分别为100.74%,103.56%,102.86%,日内和日间精密度均较好;在室温(20℃)下,盐酸恩丹西酮口服液有效期为1.5年。结论该制剂制备工艺简单,质量易于控制,稳定性较好。     

盐酸恩丹西酮缓释胶囊质量标准研究

目的:制定盐酸恩丹西酮缓释胶囊的质量标准。方法:采用 HPLC 法测定盐酸恩丹西酮的含量和溶出度。结果:盐酸恩丹西酮缓释胶囊含量在90.0%～110.0%范围内;体外释放曲线符合一级动力学方程和 Higuchi 方程;有关物质检查未见。结论:本法简便、准确,专属性强,可用于盐酸恩丹西酮缓释胶囊的质量标准研究。     

恩丹西酮注射液与顺铂、氟尿嘧啶的配伍稳定性

目的：考察室温下8h内,恩丹西酮注射液与2种抗癌药物（顺铂,氟尿嘧啶）的相互作用。方法：采用紫外分光光度法测定配伍后8h内不同时间恩丹西酮注射液与2种抗癌药物的含量及吸收曲线变化情况,同时观察外观并测定pH值。最后观察混合后的注射液薄层色谱情况。结果：在室温条件下恩丹西酮与顺铂,氟尿嘧啶在0－8h内含量,pH值均无明显变化,薄色谱未见杂斑。恩丹西酮与顺铂配伍外观无变化,但与氟尿嘧啶的混合有白色沉淀产生。     

恩丹西酮注射液与阿霉素及表阿霉素的相互作用

目的：考察了室温下8h，恩丹西酮注射液与2种抗癌药物（阿霉素、表阿霉素）的相互作用。方法：采用紫外分光度法测定配伍后8h内不同时间恩丹西酮注射液与2种抗癌药物的含量及吸收曲线变化情况，同时观察外观并测定pH值以及薄层层析检查。结果：在室温条件下，0－8h内混合液的外观、pH值、吸收曲线及含量均无明显变化，薄层层析检查未见杂斑。结论：室温下8h内恩丹西酮注射液可与上述2种药物在生理盐水中配伍作用。     

盐酸恩丹西酮乳酸羟基乙酸共聚物微球中药物的含量测定

目的:建立测定盐酸恩丹西酮乳酸羟基乙酸共聚物微球含量的方法.方法:采用二氯甲烷溶解微球后,再以水提取主药,用紫外分光光度法测定药物的含量.结果:盐酸恩丹西酮在2～20μg·ml-1的范围内,浓度与吸收度的线性关系良好,平均回收率为98.76%±0.64%,RSD为1.82%.结论:该方法操作简单、可靠,可用于快速测定微球中药物的含量.     

GYKI-46 903, a Non-Competitive Antagonist for 5-HT3 Receptors

Abstract: The effects of GYKI-46 903 ((+)endo-4-propionyloxy-6-(4-fluorophenyl)-1-azabicyclo [3.3.1]non-6-ene HCI), on 5-HT₃ receptors have been studied and compared with ondansetron in peripheral organs in vitro and in vivo, and in a receptor binding assay in membranes prepared from rat cerebral cortex. GYKI-46 903 was found to be a non-competitive antagonist at 5-HT₃ receptors present in non-stimulated longitudinal muscle strip of guinea-pig ileum (pD₂’against serotonin=5.54), and also in 5-methoxytryptamine-pretreated electrically stimulated ileal preparations (pD₂’against serotonin=5.26). On the contrary, ondansetron was found to be a competitive antagonist for 5-HT₃ receptors; the pA₂ value against serotonin was 7.40 in non-stimulated ileum, and it was 7.08 in electrically stimulated ileal preparation pretreated with 5-methoxytryptamine. In displacement studies, the pIC₅₀ values of GYKI-46 903 and ondansetron against [³H]granisetron binding to rat cerebral cortex membranes were 6.91 and 8.58 respectively. GYKI-46 903, when administered by intravenous infusion, antagonized the decrease in heart rate evoked by serotonin (Bezold-Jarisch reflex) in anaesthetized rats, and the maximal reversal was less than 50%. This was in striking contrast with ondansetron, which, after intravenous injection, completely antagonized the serotonin-induced bradycardia with an ID₅₀ value of 3.28 ug/kg. These data classify GYKI-46 903 as a non-competitive antagonist for 5-HT₃ receptors.     

A Validated HPTLC Method for Determination of Ondansetron in Combination with Omeprazole or Rabeprazole in Solid Dosage Form

A simple, precise, accurate and rapid high performance thin layer chromatographic method has been developed for the simultaneous estimation of ondansetron combinations in solid dosage form with omeprazole and rabeprazole, respectively. The method involved separation of components by TLC on a precoated silica gel 60 F₂₅₄ using a mixture of dichloromethane:methanol (9:1) as a mobile phase. Detection of spots was carried out at 309 nm and 294 nm for ondansetron with omeprazole and ondansetron with rabeprazole combinations, respectively. The mean retardation factor for ondansetron and omeprazole were found to be 0.42±0.02, 0.54±0.03, respectively while for ondansetron and rabeprazole, 0.41± 0.02 and 0.51±0.02, respectively. The linearity and range was 0.1 to 0.5 μg/spot for three drugs. The method was validated for precision, accuracy and reproducibility.     

A component of 5-HT-evoked depolarization of the rat isolated vagus nerve is mediated by a putative 5-HT4 receptor

Summary This study describes a component of 5-HT-evoked depolarization of the rat isolated vagus nerve which was unaffected by the 5-HT₃ receptor antagonist ondansetron. A grease-gap extracellular recording technique was used. Ondansetron (10–100 nmol/1) displaced the 5-HT concentration-response curve to the right yielding a pA₂ value of 8.6 (8.5–8.8), consistent with 5-HT₃ receptor antagonism, and revealing a component of the 5-HT response which was resistant to ondansetron blockade. In the presence of ondansetron (100 nmol/1) the maximum depolarization in the resistant phase was 15.5 (12.6–19.2)% of the initial maximum response to 5-HT and the pEC₅₀ value was 7.0 (6.7–7.3). The mechanism of the ondansetron-resistant component of the 5-HT response resembled a 5-HT₄ -receptor-effect in being absent in preparations equilibrated with 5-methoxytryptamine (10 mol/1) and antagonised by ICS 205930 (tropisetron, pA₂ 6.4). 5-Methoxytryptamine alone was an agonist in the vagus nerve with a maximum response similar to that of the ondansetron resistant phase of the 5-HT response. similarly renzapride alone evoked small depolarizations of this preparation but antagonized the ondansetron resistant phase of the 5-HT response (pA₂ 7.3–7.4). These effects of 5-methoxytryptamine and renzapride are also consistent with a 5-HT₄ receptor mechanism. Ketanserin (1 mol/1) and methysergide (1 mol/1) had little effect on responses to 5-HT. The depolarization evoked by this putative 5-HT₄ receptor mechanism was small but prolonged and appears to mask and after-hyperpolarizing phase of the 5-HT response in this tissue. Correspondence to: K. F. Rhodes at the above address     

Influence of 5-HT3 receptor antagonists and the indirect 5-HT agonist,dexfenfluramine, on heroin self-administration in rats

The purpose of the present study was to examine the effects of the 5-HT₃ antagonists ondansetron and MDL72222, and the 5-HT releaser and reuptake inhibitor dexfenfluramine, on intravenous heroin self-administration by Wistar rats. Using separate squads of animals, two separate schedules of heroin reinforcement were used; a relatively low dose (0.03 mg/kg per infusion) made available under a FR5 schedule for 1 h each day, and a moderate heroin dose (0.1 mg/kg per infusion) available under a FR1 schedule for 2 h each day. Following the acquisition of stable levels of responding across days, both naloxone pretreatment (0.25 mg/kg SC) and halving the heroin infusion dose produced increases in operant responding for heroin at each concentration. Neither ondansetron (0.01–1 mg/kg SC) nor MDL72222 (0.1–3 mg/kg SC) pretreatment influenced heroin self-administration. Chronic treatment (5 day) of ondansetron (0.01–0.1 mg/kg) was similarly ineffective. However, dexfenfluramine (0.5–2.5 mg/kg IP) consistently reduced heroin self-administration at doses producing only modest decreases in food responding. These findings are in contrast to place conditioning studies, which show that 5-HT₃ antagonists but not indirect 5-HT agonists block a morphine-induced place preference. Reasons for such discrepancies remain to be determined.     

Development of HPTLC method for the estimation of ondansetron hydrochloride in bulk drug and sublingual tablets

A new, simple, rapid, accurate and precise high performance thin layer chromatography (HPTLC) method has been developed for the estimation of ondansetron hydrochloride in bulk and sublingual tablets. The mobile phase composition was chloroform : ethyl acetate : methanol : ammonia (9:5:4:0.1 v/v). Spectrodensitometric analysis of ondansetron was carried out at 254 nm and a symmetrical, well‐resolved, well‐defined peak was obtained at mean retardation factor (R_f) 0.52 ± 0.02. The calibration plot was linear in the range 200‐1200 ng/spot and showed good linear relationship with coefficient of regression, R² = 0.9952 with respect to peak area. The method was validated according to the guidelines of the International Conference on Harmonization (ICH Q2(R1). The limit of detection and quantitation were 14.83 and 44.92 ng per spot, respectively. The recovery study was carried out by standard addition method and the percentage recovery was found to be 99.34 ± 1.08. Therefore it was concluded that the proposed developed HPTLC method can be applied for identification and quantitative determination of ondansetron in bulk drug and dosage forms. Copyright © 2011 John Wiley & Sons, Ltd.     

Blockade of accumbens 5-HT3 receptor down-regulation by ondansetron administered during continuous cocaine administration

The present experiment examined whether ondansetron, co-administered with continuous cocaine, would block the down regulation of accumbens 5-HT₃ receptors. Rats were exposed to a 14-day pretreatment regimen that involved the continuous infusion of 40 mg kg⁻¹ day⁻¹ cocaine or 0.9% saline via a subcutaneously implanted osmotic minipump. In addition to the continuous cocaine or saline administration, all subjects received daily subcutaneous (s.c.) injections of either vehicle or 0.1 mg kg⁻¹ ondansetron for the entire 14-day pretreatment regimen. The rats were then withdrawn from this pretreatment regimen for seven days, and slices from the nucleus accumbens obtained. The slices were perfused with 25 mM K⁺ in the absence and presence of 0, 12.5, 25, or 50 μM m-Chlorophenyl-biguanide HCl (mCPBG). The efflux samples were assayed for dopamine content by high pressure liquid chromatography (HPLC) with electrochemical detection. Continuous cocaine administration significantly attenuated the ability of mCPBG to facilitate K⁺-induce dopamine overflow compared to saline control rats. In addition, the rats that received ondansetron and cocaine during the 14-day pretreatment period, the ability of mCPBG to enhance K⁺ stimulated dopamine release was not significantly different from the saline control subjects. For all groups except the cocaine alone group, the effects of mCPBG on K⁺ stimulated dopamine release were Ca²⁺ dependent, suggesting that these effects are receptor mediated. These results suggest that continuous cocaine administration functionally down-regulates 5-HT₃ receptors in the nucleus accumbens, and that this down-regulation can be blocked by chronic ondansetron administration. Hence, a functional down regulation of accumbens 5-HT₃ receptors represents a significant contribution to the tolerance induced by continuous cocaine administration.     

Mechanism of Intestinal Absorption of Ranitidine and Ondansetron: Transport Across Caco-2 Cell Monolayers

We have investigated the transport of ranitidine and ondansetron across the Caco-2 cell monolayers. The apparent permeability coefficients (P _app) were unchanged throughout the concentration range studied, indicating a passive diffusion pathway across intestinal mucosa. No metabolism was observed for ranitidine and ondansetron during the incubation with Caco-2 cell monolayers. P _app values for ranitidine and ondansetron (bioavailability of 50 and 100% in humans, respectively) were 1.03 ± 0.17 × 10^–7 and 1.83 ± 0.055 × 10^–5 cm/sec, respectively. The P _app value for ranitidine was increased by 15- to 20-fold in a calcium-free medium or in the transport medium containing EDTA, whereas no significant change occurred with ondansetron, indicating that paracellular passive diffusion is not rate determining for ondansetron. Uptake of ondansetron by Caco-2 cell monolayers was 20- and 5-fold higher than that of ranitidine when the uptake study was carried out under sink conditions and at steady state. These results suggest that ranitidine and ondansetron are transported across Caco-2 cell monolayers predominantly via paracellular and transcellular pathways, respectively.     

Comparison of the Pharmacokinetics of an Ondansetron Solution (8 mg) When Administered Intravenously,Orally, to the Colon,and to the Rectum

Ondansetron, an antagonist of the serotonin type 3 (5-HT₃) receptor, is indicated for the treatment of chemotherapy-induced emesis. This study compares the pharmacokinetics, especially the bioavailability, of an Ondansetron 8-mg solution when administered intravenously, orally, to the colon via nasogastric intubation, and to the rectum using a retention enema. Six healthy, male volunteers received ondansetron infused into the colon during the first treatment period. These subjects then received the remaining three treatments in random order, with a minimum 1-week washout period between treatments. Serial plasma samples were obtained for up to 24 hr after dosing in each treatment period. Absolute bioavailability after the oral dosing, colonic infusion, and rectal administration averaged 71 ± 14, 74 ± 26, and 58 ± 18%, respectively. These values were not significantly different (P > 0.05). Values of T _max and C _max were also not significantly different among the nonparenteral routes. Mean absorption half-lives were 0.66, 1.1, and 0.75 hr after the oral, colonic, and rectal administrations, respectively. These results indicate that ondansetron is well absorbed in the intestinal segments studied including the upper small intestine, the colon, and the rectum and that sustained-release and suppository formulations of ondansetron are feasible.     

Nasal administration of ondansetron using a novel microspheres delivery system Part II: Ex vivo and in vivo studies

Gellan gum-based mucoadhesive microspheres of ondansetron hydrochloride for intranasal systemic delivery were prepared to avoid first pass effect, an alternative route of administration to injection and to enhance systemic bioavailability of ondansetron hydrochloride. The microspheres were prepared using spray method. The evaluation results of microspheres were reported in our previous study. The aim of this work was to study the in vivo performance of mucoadhesive microspheres in comparison with oral and intravenous preparations of ondansetron hydrochloride. The nasal delivery system gave increased AUC_0-240 and C_max as compared to those of oral delivery. In conclusion, the gellan gum-based microsphere formulation of ondansetron hydrochloride with mucoadhesive properties with increased permeation rate is promising for prolonging nasal residence time and thereby nasal absorption.     

Electrocardiographic effects of zatosetron and ondansetron,two 5HT3 receptor antagonists,in anesthetized dogs

The pharmacology of 5-hydroxytryptamine₃ (5HT₃)-antagonists is an area under active investigation, and several agents of this class are currently under development for multiple therapeutic indications. Recently, two 5HT₃ receptor antagonists of a tropane derived series, ICS 205 930 and zatosetron, have been shown to alter electrocardiographic properties of heart muscle. A prototypical, but structurally distinct (imidazole) 5HT₃-antagonist, ondansetron, was examined for its comparative cardiovascular activity in anesthetized dogs at intravenous doses of 0.66–5.25 mg/kg. Similar to zatosetron, a significant, dose-dependent prolongation of the duration of the action potential of the electrocardiogram (Q-T_c interval) occurred following ondansetron exposure, with a maximum increase of 28%. Other cardiovascular parameters (heart rate, mean arterial pressure, pulmonary pressure, cardiac output, peripheral vascular resistance, stroke volume and work index) were essentially unchanged by ondansetron treatment. At equivalent 5HT₃ blocking doses, both ondansetron and zatosetron prolonged the Q-T_c interval in anesthetized dogs similarly. However, for both compounds, the doses required to increase Q-T_c interval were higher than the doses required to demonstrate 5HT₃ receptor blockade. The fact that ondansetron, an imidazole, exhibited electrophysiological effects on cardiac muscle like the 5HT₃ receptor antagonists derived from tropane suggests that the electrocardiographic effects are related to some property shared by 5HT₃ receptor antagonists rather than a property of the tropane structure.