Metoclopramide, 4-amino-5-chloro-2-methoxy-N-(2-diethyl-amino-ethyl) benzamide, a procaine derivative with antiemetic activity, is currently-used in gastro-intestinal diagnostics and in the treatment of various types of gastro-intestinal disorders. Metoclopramide increases the tone and peristalsis of the stomach and duodenum, distends the duodenal bulb and improves the pyloric activity, thus promoting gastric motility and reducing gastric emptying time. This effect of metoclopramide has led to the modification of the absorption of other drugs when administered concomitantly (e.g. digoxin, griseofulvin, the salicylates, and levodopa.) Despite the pharmacological and therapeutic knowledge accumulated in the literature, little pharmacokinetic information pertaining to this drug is available. This is due, in part, to the lack of a highly sensitive assay to quantitate trace amounts of the drug in small volume biological samples. This thesis reports a highly sensitive GLC-ECD assay which is capable of detecting picogram amounts of metoclopramide in the biological fluids in rats. This method involves extraction, derivatization, removal of excess derivatizing agent and quantitation by injecting the derivative solution into a Reporting GLC-ECD. The structure of the derivative was confirmed by using GC/MS electron impact and chemical ionization methods. The optimized conditions are described as follows: Purification - After extraction and drying, the free base was recrystallized three times with, benzene. The crystals were dried at 125°C under vacuum for 2 hrs. This process removed any volatile substances such as benzene. The purity of the free base was confirmed by differential scanning calorimetry. Extraction - Pesticide grade benzene was found to be the best solvent for extraction due to its high purity and satisfactory extraction efficiency for the drug after alkalinization of the aqueous layer with 1 ml of 1 N NaOH. The optimum aqueous and organic ratio for extraction was 1 to 3, viz., 2 ml of the aqueous layer was extracted with 6 ml of benzene. Extraction was accomplished by shaking the aqueous and the organic mixture on a wrist-action shaker for 20 minutes. After centrifugation, 5 ml of the organic phase from a sample was pipetted into a separate 15 ml centrifuge tube. One ml of diazepam solution (750 mcg/ml in benzene) was added to each tube. The content was dried under a gentle stream of nitrogen. The residue was reconstituted with 1 ml of benzene. Derivatization - Twenty ul of heptafluorobutyric anhydride was added to the reconstituted sample. The reaction mixture was incubated at 55°C for 20 minutes. Removal of excess derivatizing agent - The removal of the excess derivatizing agent was achieved by hydrolysis with 0.5 ml of water and neutralization with 0.5 ml of 4% ammonium hydroxide solution. GLC - One ul of the derivative solution was injected into a GLC-ECD with the following conditions: injection temperature: 250°C oven temperature: 250°C carrier gas(95%/5% argon/methane) flow rate: 40 ml/ min. A 1.8 m, 2 mm i . d . glass column packed with 3% OV-17 coated on Chromosorb W (80-100 mesh) was used. GLC/MS - The structure of the HFB derivative was elucidated by GLC-electron impact mass spectrometry. The following conditions were used: injection temperature: 250°C column temperature: 250°C carrier gas (helium) flow rate: 40 ml/min A 1.8 m, 2 mm i.d. glass column packed with 3% 0V-17 coated on Chromosorb W (80-100 mesh) was used. ionization beam energy: 70 eV electron multiplier voltage: 2 Kv analyser temperature: 50°C separator oven temperature: 200°C Since the molecular ion was not readily discernable from the electron impact mass spectrum, chemical ionization mass spectrometry was used to identify the molecular ion. The following conditions were used: probe temperature: 200°C source temperature: 150 C ionization voltage: 70 V ionizing gas: isobutane samples were introduced by direct probe method Quantitative studies - A calibration curve was prepared for the plasma extracts. Linearity was observed in the range studied (91-750 ng/ml). The recovery of drug spiked separately into plasma, whole blood and urine was 85%. This assay is extremely sensitive and specific. The lowest detectable amount of metoclopramide i s 1 pcg. Animal studies - The applicability of this assay technique was shown by studying the elimination kinetics of the drug in the rat. The time course of the drug elimination after an i.v. dose can be described by a biexponential equation. The half-life calculated was 49.75 - 8 minutes. / Pharmaceutical Sciences, Faculty of / Graduate

Metoclopramide (MCP) is a potent antinauseant/ antiemetic and gastrointestinal motility modifier. MCP finds clinical use in a wide variety of situations and is administered on both an acute and chronic basis. This thesis examines the pharmacokinetics of MCP in both normal, healthy volunteers and in uremic subjects on a maintenance hemodialysis program. Specifically, in the normal, healthy volunteers, the dose-linearity, and absolute and relative bioavailabilities are examined. In the uremics, the effects of chronic renal failure on MCP kinetics, the removal of MCP by hemodialysis, and the effects of hemodialysis on MCP kinetics are examined. Based on early reports, the pharmacokinetics of MCP were claimed to be dose-dependent and the absolute bioavailability extremely variable. However, many of these early studies suffered from methodological problems which limit the credibility of their findings. Based on a four-way crossover study involving six normal, healthy volunteers we find, in contrast to previous results, that the kinetics of MCP are linear over the dose range of 5 -20 mg, the absolute bioavailability is 76 ± 38 %, and the relative bioavailability of a solution dosage form vs the tablet dosage form is approximately 1. Although renal clearance accounts for only about 20 % of the total body clearance of MCP in normals, uremia has been shown to substantially alter MCP kinetics in both rat and man. There appears to be at least a two-fold decrease in total body clearance with an attendent, proportional increase in elimination half-life and insignificant change in volume of distribution. Hemodialysis is relatively ineffective in clearing MCP from the body and this inefficiency is probably related to the relatively large volume of distribution of MCP. Hemodialysis also has no effects on the apparent kinetic parameters following its termination. In addition, results from a single patient who received a kidney transplant show that the renewed renal function is accompanied by an apparent reversion of all kinetic parameters to within normal limits within 15 days of transplantation. / Pharmaceutical Sciences, Faculty of / Graduate

Thesis (doctoral)--Lund University, 1998. / Added t.p. with thesis statement inserted. Includes bibliographical references.

Thesis (doctoral)--Lund University, 1998. / Added t.p. with thesis statement inserted. Includes bibliographical references.

O jejum prolongado, utilizado como preparação para a gastroscopia em equinos, não proporciona um completo esvaziamento gástrico. Para avaliar a eficácia da lavagem gástrica e de três procinéticos na preparação para o exame gastroscópico, foram utilizados seis equinos adultos, sem alterações clínicas, que passaram por quatro horas de jejum e quatro protocolos: G1- lavagem gástrica; G2- betanecol (0,04mg/kg VO); G3- metoclopramida (0,12mg/kg SC) e G4- lidocaína (1,3mg/kg IV). Após a lavagem ou administração de uma das medicações (duas horas após o betanecol ou uma hora após as demais) foi realizada a gastroscopia. As avaliações foram feitas por um profissional que conhecia o grupo experimental dos equinos (P1) e outro que desconhecia a informação (P2), sem diferença estatística entre suas avaliações. Em todos os exames foi observado conteúdo gástrico, com predominância de conteúdo líquido no G1 e de sólido a misto nos demais. Para o P1, a média de visualização da mucosa aglandular foi 95,0±0,0% no G1, 74,1±17,4% no G2, 88,3±4,0% no G3 e 90,0±6,3% no G4, com diferença estatística entre G1 e G2 e entre G2 e G4. Para a mucosa glandular, a média de visualização foi de 45,8±8,6% no G1, 29,1±10,6% no G2, 31,6±10,3% no G3 e 34,1±9,1% no G4, com diferença estatística entre G1 e G2. Na classificação geral, o melhor exame foi o do G1 e o pior o do G2. Conclui-se que a lavagem gástrica pode ser usada como preparação para o exame gastroscópico em equinos. De acordo com o protocolo testado, o betanecol é o menos indicado para esta finalidade. Embora sejam necessários mais estudos, o uso de procinéticos antes do exame gastroscópico em equinos mostra-se promissor, com resultados semelhantes aos observados com períodos de jejum mais prolongados. / Prolonged fasting in horses (12 - 24 hours), as a preparation for gastroscopy, does not permit complete gastric emptying. Six healthy adult horses were used to evaluate the efficacy of gastric lavage and the use of three prokinetics. Horses with held from feed for four hours were submitted to four protocols: G1 - gastric lavage; G2 - bethanechol (0,04mg/kg PO); G3 - metoclopramide (0,12mg/kg SC) and G4 - lidocaine (1,3mg/kg IV). Gastroscopy was performed: immediately (G1); two hours following admnistration (G2); one hour following administration (G3 and G4). To reduce bias gastric examination was conducted by two professionals: the first (P1), aware of the protocol and the second (P2) was kept blind. No significant difference was seen between them. Gastric content was predominantly liquid in G1 and solid or mixed in the other three groups. The average observation of the aglandular mucosa of P1 was: 95,0±0,0% for G1, 74,1±17,4% for G2, 88,3±4,0% for G3 and 90,0±6,3% for G4. Significant difference was observed between G1 and G2 and between G2 and G4. Observation of the glandular mucosa was: 45,8±8,6% for G1, 29,1±10,6% for G2, 31,6±10,3% for G3 and 34,1±9,1% for G4. Groups G1 and G2 were significantly different. Considering all classification criteria, G1 and G2 protocols permitted respectively the best and worst evaluations. It was concluded that gastric lavage is indicated for preparing horses for gastroscopy, the bethanechol protocol here tested is the least indicated. Although more studies are necessary, the use of prokinectics prior to gastroscopy in horses seems promising, producing results similar to those observed in long fasting periods.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / IntroduÃÃo: A mucosite induzida por antineoplÃsicos à um fator limitante na terapia anticÃncer. Mucosite à um termo clÃnico que descreve uma sÃndrome caracterizada por reaÃÃo inflamatÃria da mucosa de todo o trato digestivo com ulceraÃÃes. A mucosite intestinal por antineoplÃsicos desencadeia alteraÃÃes da motilidade digestiva. A dexametasona à um glicocorticÃide cujo principal efeito farmacolÃgico decorre de sua aÃÃo antiinflamatÃria e imunossupressora Objetivos: Investigar a dismotilidade gastrintestinal associada à mucosite intestinal induzida por irinotecano em camundongos, bem como avaliar o efeito da modulaÃÃo farmacolÃgica da resposta inflamatÃria sobre estas alteraÃÃes motoras. MÃtodos: Camundongos Swiss machos (20â25g) foram tratados do D1-D4 com irinotecano (75 mg/Kg, i.p.) ou com salina (0,1ml, i.p.), o sacrificio foi realizado no sÃtimo dia experimental. Afim de estudar alteraÃÃes relacionadas à mucosite intestinal, amostras do duodeno, jejuno e Ãleo, foram removidas para avaliar a injÃria epitelial por morfometria, escores histolÃgicos, e atividade de MPO, tendo a diarrÃia sido avaliada antes do sacrifÃcio. Para avaliaÃÃo de citocinas amostras de duodeno foram retiradas e pelo mÃtodo de ELISA foi determinada a concentraÃÃo de TNF-, IL-1, KC e IL-10. Para avaliar a motilidade digestiva, os animais foram deixados em jejum de 18 horas do D6 para o D7. No D7, foram administrados 350ÂL da soluÃÃo glicosada (5%) contendo vermelho de fenol (VF) a 0,75 mg/ml em cada animal antes do sacrifÃcio. ApÃs os tempos de 10, 20 e 30 min, os animais foram sacrificados e submetidos a uma laparotomia mediana, sendo o estÃmago retirado completamente e o intestino delgado divido em 3 partes iguais: proximal, medial e distal. A seguir o esvaziamento gÃstrico, trÃnsito intestinal e transito gastrintestinal (centro geomÃtrico) foram determinados por espectofotometria. A seguir, em outro grupo experimental, foi avaliado se a modulaÃÃo farmacolÃgica do processo inflamatÃrio poderia reverter Ãs alteraÃÃes da motilidade digestiva associadas à mucosite por irinotecano. Para tanto, dexametasona (2,5mg/kgm s.c.) ou metoclopramida (10mg/kg i.p.) do D1-D7, foram administradas 30 minutos antes da administraÃÃo de irinotecano. A seguir foram avaliados todos os parÃmetros descritos acima. Resultados: O tratamento com irinotecano foi capaz de induzir uma lesÃo intestinal com um importante comprometimento da barreira epitelial funcional com a presenÃa das seguintes alteraÃÃes: diarrÃia, leucopenia, encurtamento acentuado das vilosidades intestinais, necrose parcial de criptas, aumento da atividade de MPO, aumento na concentraÃÃo de KC e IL-1 e retarde do esvaziamento gÃstrico e transito gastrontestinal e aceleraÃÃo do transito intestinal. O tratamento com dexametasona, mas nÃo metoclopramida, reduziu significativamente as lesÃes intestinais, com recuperaÃÃo da altura dos vilos, da profundidade das criptas, diminuiÃÃo da atividade de MPO, reduÃÃo da concentraÃÃo de IL-1. Ademais, somente o tratamento com dexametasona, mas nÃo por metoclopramida, foi capaz de reverter retarde do esvaziamento gÃstrico, bem como a aceleraÃÃo do trÃnsito gastrintestinal. ConclusÃo: A mucosite intestinal induzida por irinotecano foi capaz de causar dismotilidade e resposta inflamatÃria gastrintestinal com participaÃÃo de KC e IL1 a qual se associa com o retarde do esvaziamento gÃstrico e trÃnsito gastrintestinal e aceleraÃÃo do trÃnsito intestinal. ConcluÃmos ainda que a dexametasona, mas nÃo metoclopramida, reduziu a resposta inflamatÃria e modulou parcialmente a dismotilidade gastrintestinal associada à mucosite por iriniotecano. / Introduction: Mucositis induced by antineoplasic drugs is a limiting factor in anticancer therapy. Mucositis is a clinical term which describes a syndrome characterized by mucosal ulceration of the entire digestive tract. Mucositis results from intestinal inflammatory events, which induces changes in gastrointestinal motility. Dexamethasone is a glucocorticoid whose main pharmacological effect is anti-inflammatory and immunosuppressive. Objectives: To investigate the gastrointestinal dismotility associated with irinotecan-induced intestinal mucositis in mice and to assess the effect of pharmacological modulation of the inflammatory response on these motor abnormalities. Methods: Swiss male mice (20-25g) were treated in the D1-D4 with irinotecan (75 mg / kg, ip) or saline (0.1 ml, ip), the sacrifice was performed on the seventh day trial in order to study changes related to intestinal mucositis. Samples of duodenum, jejunum and ileum were removed to assess the epithelial injury by morphometry, histological scores and MPO activity, and diarrhea were evaluated before sacrifice. For evaluation of cytokine samples of duodenum were removed and the ELISA was determined concentrations of TNF-, IL-1 , KC and IL-10. In order to evaluate gastrointestinal motility, the animals were kept fasting for 18 hours from D6 to D7. In D7, were administered 350μL of glucose solution (5%) containing phenol red (VF) to 0.75 mg / ml in each animal prior to sacrifice. After the times of 10, 20 and 30min, animals were sacrifice. Stomach was totally removed, and small intestine was divided into 3 parts: proximal, medial and distal. The gastric emptying, intestinal transit and gastrointestinal transit were determinate by spectrofotometry. In other experimental group, we evaluated if pharmacological modulation of the inflammatory process could reverse the gastrointestinal dismotility associated with irinotecan- induced intestinal mucositis. Then, dexamethasone (2.5 mg / kg sc) or metoclopramide (10mg/kg ip) of D1-D7 were administrated 30 minutes before irinotecan administration and all of parameters described before were evaluated Results: Treatment with irinotecan was able to induce an intestinal lesion with significant impairment of epithelial barrier function in the presence of the following changes: diarrhea, leukopenia, marked shortening of the villus, crypts of partial necrosis, increase im MPO activity, increased concentrations of IL-1  and changes in gastrointestinal motility. Treatment with dexamethasone, but not with metoclopramide, significantly reduced the intestinal lesions, with recovery of villous height, crypt depth, decreased MPO activity, reduced concentrations of IL-1. In addition, dexamethasone, but not metoclopramide, was able to reverse the delay in gastric emptying and increase in intestinal transit. Conclusion: The intestinal mucositis induced by irinotecan was able to cause gastrointestinal dismotility and inflammatory response with the participation of KC and IL1 which is associated with delay gastric emptying and gastrointestinal transit and acceleration of intestinal transit. It is also concluded that dexamethasone, but not metoclopramide, reduced the inflammatory response and modulated in part the gastrointestinal dismotility associated with irinotecan-induced intestinal mucositis.

The drug metoclopramide was found to adsorb to the unionized and ionized silica surface. The primary objective of this research was to use potentiometric titration in order to study the specificity of the interactions of benzamide analogs with the hydroxyl groups, silanols, on the Aeroperl® silica surface. Mass titration studies showed that the acidity of surface silanols increases with dissolved metoclopramide and similar compounds. The nature of the interaction was concluded to involve a physical adsorption process. A different potentiometric titration method was devised to determine the ionization of silanols in the presence of a dissolved compound with solubility limitations. This method was found to give similar results as that described in the literature. The presence of dissolved metoclopramide was found to cause a large increase in the density of the negatively charged silanols on the silica surface. The ionization of silica was dependent on the concentration of dissolved metoclopramide at low pH but was found to be constant over a wide concentration range at pH 7.0 or higher. Adsorption studies with unionized silica indicated that specific interactions with the surface silanols occur as well as non-specific interactions driven by hydrophobic bonding with the surface siloxane groups. There was an increase in the adsorption of metoclopramide with increasing ionization of the silica surface which suggested that the negatively charged silanols constituted an additional adsorption site. The mechanism of the interaction was elucidated by potentiometric titration with various probe compounds. The titration data with lidocaine suggested that the ionization of the surface silanols is influenced by specific interactions with the adsorbed compound rather than concentration effects. The ionized site density of silica was found to be related to the relative magnitude of the aromatic π-electron density of the adsorbed benzamides. A comparison of these titration data with that of triethylamine indicated that ionic interactions between the positively charged amine groups and the negatively charged silanols are likely to be occurring. Based on the difference in chemical structure, the titration data with dissolved ephedrine indicated that the other site of interaction is likely to be between the carbonyl oxygen of the adsorbed benzamides and the unionized silanols. The pH dependence of the ionization of silanols for both adsorption sites suggested that silanols interact simultaneously with several functional groups on a single adsorbed molecule.

O jejum prolongado, utilizado como preparação para a gastroscopia em equinos, não proporciona um completo esvaziamento gástrico. Para avaliar a eficácia da lavagem gástrica e de três procinéticos na preparação para o exame gastroscópico, foram utilizados seis equinos adultos, sem alterações clínicas, que passaram por quatro horas de jejum e quatro protocolos: G1- lavagem gástrica; G2- betanecol (0,04mg/kg VO); G3- metoclopramida (0,12mg/kg SC) e G4- lidocaína (1,3mg/kg IV). Após a lavagem ou administração de uma das medicações (duas horas após o betanecol ou uma hora após as demais) foi realizada a gastroscopia. As avaliações foram feitas por um profissional que conhecia o grupo experimental dos equinos (P1) e outro que desconhecia a informação (P2), sem diferença estatística entre suas avaliações. Em todos os exames foi observado conteúdo gástrico, com predominância de conteúdo líquido no G1 e de sólido a misto nos demais. Para o P1, a média de visualização da mucosa aglandular foi 95,0±0,0% no G1, 74,1±17,4% no G2, 88,3±4,0% no G3 e 90,0±6,3% no G4, com diferença estatística entre G1 e G2 e entre G2 e G4. Para a mucosa glandular, a média de visualização foi de 45,8±8,6% no G1, 29,1±10,6% no G2, 31,6±10,3% no G3 e 34,1±9,1% no G4, com diferença estatística entre G1 e G2. Na classificação geral, o melhor exame foi o do G1 e o pior o do G2. Conclui-se que a lavagem gástrica pode ser usada como preparação para o exame gastroscópico em equinos. De acordo com o protocolo testado, o betanecol é o menos indicado para esta finalidade. Embora sejam necessários mais estudos, o uso de procinéticos antes do exame gastroscópico em equinos mostra-se promissor, com resultados semelhantes aos observados com períodos de jejum mais prolongados. / Prolonged fasting in horses (12 - 24 hours), as a preparation for gastroscopy, does not permit complete gastric emptying. Six healthy adult horses were used to evaluate the efficacy of gastric lavage and the use of three prokinetics. Horses with held from feed for four hours were submitted to four protocols: G1 - gastric lavage; G2 - bethanechol (0,04mg/kg PO); G3 - metoclopramide (0,12mg/kg SC) and G4 - lidocaine (1,3mg/kg IV). Gastroscopy was performed: immediately (G1); two hours following admnistration (G2); one hour following administration (G3 and G4). To reduce bias gastric examination was conducted by two professionals: the first (P1), aware of the protocol and the second (P2) was kept blind. No significant difference was seen between them. Gastric content was predominantly liquid in G1 and solid or mixed in the other three groups. The average observation of the aglandular mucosa of P1 was: 95,0±0,0% for G1, 74,1±17,4% for G2, 88,3±4,0% for G3 and 90,0±6,3% for G4. Significant difference was observed between G1 and G2 and between G2 and G4. Observation of the glandular mucosa was: 45,8±8,6% for G1, 29,1±10,6% for G2, 31,6±10,3% for G3 and 34,1±9,1% for G4. Groups G1 and G2 were significantly different. Considering all classification criteria, G1 and G2 protocols permitted respectively the best and worst evaluations. It was concluded that gastric lavage is indicated for preparing horses for gastroscopy, the bethanechol protocol here tested is the least indicated. Although more studies are necessary, the use of prokinectics prior to gastroscopy in horses seems promising, producing results similar to those observed in long fasting periods.

No description available.

Gastroparesis is a disorder characterized by delayed gastric emptying due to chronic abnormal gastric motility. Prokinetic agents such as domperidone and metoclopramide are the cornerstone in treatment of gastroparesis. Although these medications have been used for decades, essential information about their metabolism is not available. Lack of knowledge about the metabolites formed in the body upon administration of the aforementioned medications as well as the enzymes involved in their metabolism limits key information needed to make sound medical decisions. Accurate and comprehensive identification of the metabolites along with reaction phenotyping of prokinetic agents will ensure safe and effective use of these drugs and hence enhance the clinical outcome. The thesis starts with an introductory chapter which comprises a comprehensive literature review on gastroparesis and the available pharmacological treatment options. The chapter also emphasizes the importance of metabolic profiling of prokinetic agents (domperidone and metoclopramide) and its impact on enhancing the safety and efficacy of these medications. Chapter 2 of this project was aimed to determine phase oxidative and conjugative metabolites of domperidone in the plasma and urine of gastroparesis patients using tandem mass spectrometry. First, the metabolites were identified in in-vitro human subcellular fractions. The knowledge gained in this experiment helped identifying the metabolites in the biological fluids of patients. In total, 12 metabolites including 7 new metabolites were identified, 5 of which were not reported previously. Chapter 3 aimed to identify the cytochrome P450 (CYP) enzymes responsible for the metabolism of metoclopramide. The parent depletion approach was used and a novel LC-MS/MS method was developed and validated to enable metoclopramide quantification. CYP2D6 was showed to the predominant isoform in metoclopramide metabolism; other isoforms also contribute to a minor extent. Chapter 4 discusses the possibility of potential drug-drug interaction (DDI) in the current management practice of gastroparesis. We identified and investigated some frequently used drug combinations that are known to share common metabolic pathways. Domperidone in combination with pioglitazone and ondansetron was evaluated. Results showed that pioglitazone inhibited domperidone metabolism in-vitro. Our experiments did not predict a DDI for the domperidone - ondansetron combination. In summary, the ultimate goal of this thesis was to improve the management of gastroparesis by increasing information about the metabolic disposition of prokinetic agents and to investigate the magnitude of putative drug combinations. The knowledge provided by this work will help in making more effective and less hazardous clinical decisions which will ultimately lead to more successful gastroparesis management. / Pharmaceutical Sciences