Neutralization of Acidic Tumor Microenvironment (TME) with Daily Oral Dosing of Sodium Potassium Citrate (K/Na Citrate) Increases Therapeutic Effect of Anti-cancer Agent in Pancreatic Cancer Xenograft Mice Model.

Extracellular pH (pHe) of tumor cells is characteristic of tumor microenvironment (TME). Acidic TME impairs the responses of tumors to some anti-cancer chemotherapies. In this study, we showed that daily oral dosing of sodium potassium citrate (K/Na citrate) increased blood HCO3- concentrations, corresponding to increase of HCO3- concentrations and pHs in urine, and neutralized the tumor pHe. Neutralization of acidic TME by alkaline substance like HCO3-, an active metabolite of K/Na citrate, well potentiated the therapeutic effect of anticancer agent TS-1®, an orally active 5-fuluoro-uracil derivative, in Panc-1 pancreatic cancer-xenograft murine model. Neutralization of acidic TME by using an alkaline K/Na citrate is a smart approach for enhancement of the therapeutic effects of anticancer agents for pancreatic cancer in the end stage.

Oral absorption and drug interaction kinetics of moxifloxacin in an animal model of weightlessness.

To investigate the effect of simulated weightlessness on the pharmacokinetics of orally administered moxifloxacin and the antacid Maalox or the antidiarrheal Pepto-Bismol using a tail-suspended (TS) rat model of microgravity. Fasted control and TS, jugular-vein-cannulated, male Sprague-Dawley rats received either a single 5 mg/kg intravenous dose or a single 10 mg/kg oral dose of moxifloxacin alone or with a 0.625 mL/kg oral dose of Maalox or a 1.43 mL/kg oral dose of Pepto-Bismol. Plasma concentrations of moxifloxacin were measured by HPLC. Pharmacokinetic data were analyzed using WinNonlin. Simulated weightlessness had no effect on moxifloxacin disposition after intravenous administration but significantly decreased the extent of moxifloxacin oral absorption. The coadministration of moxifloxacin with Maalox to either control or TS rats caused significant reductions in the rate and extent of moxifloxacin absorption. In contrast, the coadministration of moxifloxacin with Pepto-Bismol to TS rats had no significant effect on either the rate or the extent of moxifloxacin absorption. These interactions showed dose staggering when oral administrations of Pepto-Bismol and moxifloxacin were separated by 60 min in control rats but not in TS rats. Dose staggering was more apparent after the coadministration of Maalox and moxifloxacin in TS rats.

Potential Implications of Gut Microbiota in Drug Pharmacokinetics and Bioavailability.

Gut microbial communities are capable of enzymatically transforming pharmaceutical compounds into active, inactive, and toxic metabolites, thus potentially affecting the pharmacokinetics and bioavailability of orally administered medications. Our understanding of the impact and clinical relevance of how gut microbial communities can directly and indirectly affect drug metabolism and, ultimately, clinical outcomes, is limited. Interindividual variability of gut microbial composition may partially explain differences observed in drug efficacy and toxicity in certain patient populations. This review provides an overview of how gut microbial communities can potentially contribute to individual drug response. This review focuses on the current landscape of clinical and preclinical research that defines the microbiome contribution on medication response with the goal of improving medication efficacy and decreasing medication toxicity.

Effect of an Al/Mg Hydroxide Antacid and Food on the Pharmacokinetics of Dexibuprofen.

OBJECTIVES: In this communication we report an important findings, the effect of Al/Mg hydroxide antacid and food on the pharmacokinetics of dexibuprofen when administered concomitantly. METHODS: Subjects were divided into four groups, each containing 6 subjects, to evaluate the effect of antacid and food on pharmacokinetic of dexibuprofen. A new HPLC method was developed and validated for plasma sample analysis. Mobile phase was comprised of Acetonitrile: Methanol: 0.05M Phosphate buffer (40:10:50), pH was adjusted to 6.85±0.01 with NaOH. Mobile phase was eluted through C18-ODS column and drug was detected at 223 nm. Plasma was obtained and stored at - 70°C until analysis. Drug was extracted from each plasma sample of volunteer and quantified by using HPLC technique. RESULTS: A decrease in dexibuprofen absorption was observed in Test Group-1 when administered with Antacid as compared to Controlled Group-1. Mean Cmax values showed a significant (p value 0.035) decrease from 44.14±2.3 to 33.1±0.8 µg/mL. Tmax, Area under curve, t1/2, Cl, Vd and Ke were not affected significantly. AUC increased from 195.7±8.9 µg.hr/mL to 222.8±14.7 µg.hr/mL. In contrast, test Group-2 showed an increase in dexibuprofen absorption. t1/2 increased significantly from 4.505±0.19 hrs to 6.216±0.36 hrs whereas Ke reduced from 0.159±0.00 to 0.116±0.006 hrs-1. Cmax increased from 44.877±2.263 to 51.721±0.096 µg/mL. CONCLUSION: It is concluded that concomitant intake of Al/Mg hydroxide antacid or food with dexibuprofen has an impact to significantly alter its pharmacokinetic parameters.

Formulation, optimization, and evaluation of raft-forming formulations containing Nizatidine.

OBJECTIVE: The main objective of this research is to formulate, optimize, and evaluate raft-forming chewable tablets of Nizatidine. Various raft-forming agents were used in preliminary screening. Sodium alginate showed maximum raft strength, so tablets were prepared using sodium alginate as the raft forming agent, along with calcium carbonate (CaCO3) as antacid and raft strengthening agent, and sodium bicarbonate (NaHCO3) as a gas generating agent. RESEARCH DESIGN AND METHODS: Raft forming chewable tablets containing Nizatidine were prepared by direct compression and wet granulation methods, and evaluated for drug content, acid neutralization capacity, raft strength, and in-vitro drug release in 0.1 N HCl. Box-Behnken design was used for optimization. RESULTS: Two optimized formulations were predicted from the design space. The first optimized recommended concentrations of the independent variables were predicted to be X1 = 275.92 mg, X2 = 28.60 mg, and X3 = 202.14 mg for direct compression technique and the second optimized recommended concentrations were predicted to be X1 = 253.62 mg, X2 = 24.60 mg, and X3 = 201.77 mg for wet granulation technique. Optimized formulations were stable at accelerated environmental testing for six months at 35 °C and 45 °C with 75% relative humidity. X-Ray showed that the raft floated immediately after ingestion and remained intact for ∼3 h. CONCLUSION: Raft was successfully formed and optimized. Upon chewing tablets, a raft is formed on stomach content. That results in rapid relief of acid burning symptoms and delivering the drug into systemic circulation with enhanced bioavailability.

A physiologically-based pharmacokinetic model adequately predicted the human pharmacokinetic profiles of YH4808, a novel K+-competitive acid blocker.

A physiologically-based pharmacokinetic (PBPK) model was developed for YH4808, a novel potassium-competitive acid blocker, using the SimCYP® Simulator based on the physicochemical, in vitro preclinical and clinical data of YH4808. The PBPK model was optimized using YH4808 concentrations obtained from the single-dose phase I clinical trial. Overall, the PBPK model adequately predicted the observed pharmacokinetic profiles of YH4808 in humans. The pharmacokinetic profiles of YH4808 after multiple oral administrations were predicted using a refined PBPK model. The ratios of model-predicted to observed Cmax, AUCinf and AUCτ values on Day 1 and Day 7 at 100 mg were 0.7-1.0. However, the model failed to predict a decreased exposure after multiple oral administration particularly at higher doses of 200 and 400 mg. The reduced solubility of YH4808 at higher pH was hypothesized as the main cause of the reduction in exposure such that absorption was decreased as pH was increased. This hypothesis was confirmed by PBPK modeling and simulation, where intragastric pH was increased by YH4808.

Effect of food on the pharmacokinetics of YH4808, a potassium-competitive acid blocker, after single- and multiple-oral dosing in healthy subjects.

PURPOSE: YH4808 is a potassium-competitive acid blocker, developed for the treatment of acid-related disorders. Two clinical studies in healthy male subjects were conducted to evaluate the effect of food on the pharmacokinetics of YH4808. METHODS: The first study, a randomized, three-treatment, three-period, crossover study, compared pharmacokinetics of YH4808 (300 mg) after a single dose at fed state with a standard or a high-fat meal to those at fasted state. The second study, a randomized, two-treatment, two-period, crossover study, investigated pharmacokinetics at fasted or fed state with a standard meal after twice daily dose of YH4808 (100 mg) for 7 days. Bloods for pharmacokinetic evaluation were sampled up to 48 h post-dose and 24 h post-dose at steady state, respectively. The pharmacokinetic parameters were estimated by non-compartmental method. RESULTS: After single dosing, the geometric means of maximum plasma concentration increased by 1.2 and 2.1 times in the fed states with a standard meal and a high-fat meal, respectively, of that in fasted state. Corresponding values of area under the plasma concentration-time curve (AUC) from time 0 to the last measurable time point increased by 1.8 and 2.8 times, respectively. After multiple dosing, the geometric mean for 24-h AUC at steady state slightly increased in fed state by 1.1 times of that in fasted state. CONCLUSIONS: As fat content of the food increased, the systemic exposure of YH4808 after single dosing increased. However, systemic exposures at steady state after multiple dosing between fasted and fed states were similar. TRIAL REGISTRATION: ClinicalTrials.gov registry no.: NCT01520012.

Pyruvate is a prospective alkalizer to correct hypoxic lactic acidosis.

Type A lactic acidosis resulted from hypoxic mitochondrial dysfunction is an independent predictor of mortality for critically ill patients. However, current therapeutic agents are still in shortage and can even be harmful. This paper reviewed data regarding lactic acidosis treatment and recommended that pyruvate might be a potential alkalizer to correct type A lactic acidosis in future clinical practice. Pyruvate is a key energy metabolic substrate and a pyruvate dehydrogenase (PDH) activator with several unique beneficial biological properties, including anti-oxidant and anti-inflammatory effects and the ability to activate the hypoxia-inducible factor-1 (HIF-1α) - erythropoietin (EPO) signal pathway. Pyruvate preserves glucose metabolism and cellular energetics better than bicarbonate, lactate, acetate and malate in the efficient correction of hypoxic lactic acidosis and shows few side effects. Therefore, application of pyruvate may be promising and safe as a novel therapeutic strategy in hypoxic lactic acidosis correction accompanied with multi-organ protection in critical care patients.

Helicobacter pylori: past, current and future treatment strategies with gastroretentive drug delivery systems.

Helicobacter pylori have been subject to intense investigation since its discovery from gastric biopsy in 1982. This gastropathogen has been regarded as serious public health problem due to its association with dyspepsia, gastritis, gastroduodenal ulcers, mucus-associated lymphoid tissue lymphoma and gastric carcinoma. In vivo eradication of established H. pylori infections is difficult due to several factors such as gastric niche, coccoid form due to sub-minimum inhibitory concentration of antimicrobials, bacterial load, primary antibiotic resistance, patient compliance and stability of therapeutics in gastric acid secretion. Considering these factors, a logical way to improve the outcome of the treatment is to develop dosage forms which are able to deliver the anti-helicobacter agents in the gastric niche for both local and systemic actions, simultaneously taking care of stability of therapeutics in acidic environment. Such dosage forms, which are popularly known as gastro retentive drug delivery systems (GRDDS), have the immense potential to effectively counter the problem of high bacterial load; prevent induction of coccoid bacteria thereby improving treatment outcome and compliance. This review describes efficacy of various therapeutic agents, treatment strategies and status of different GRDDS until now.

Managing potential drug-drug interactions between gastric acid-reducing agents and antiretroviral therapy: experience from a large HIV-positive cohort.

Drug-drug interactions between antiretroviral therapy and other drugs are well described. Gastric acid-reducing agents are one such class. However, few data exist regarding the frequency of and indications for prescription, nor risk assessment in the setting of an HIV cohort receiving antiretroviral therapy. To assess prevalence of prescription of gastric acid-reducing agents and drug-drug interaction within a UK HIV cohort, we reviewed patient records for the whole cohort, assessing demographic data, frequency and reason for prescription of gastric acid-reducing therapy. Furthermore, we noted potential drug-drug interaction and whether risk had been documented and mitigated. Of 701 patients on antiretroviral therapy, 67 (9.6%) were prescribed gastric acid-reducing therapy. Of these, the majority (59/67 [88.1%]) were prescribed proton pump inhibitors. We identified four potential drug-drug interactions, which were appropriately managed by temporally separating the administration of gastric acid-reducing agent and antiretroviral therapy, and all four of these patients remained virally suppressed. Gastric acid-reducing therapy, in particular proton pump inhibitor therapy, appears common in patients prescribed antiretroviral therapy. Whilst there remains a paucity of published data, our findings are comparable to those in other European cohorts. Pharmacovigilance of drug-drug interactions in HIV-positive patients is vital. Education of patients and staff, and accurate data-gathering tools, will enhance patient safety.

Drug Interactions with the Direct-Acting Antiviral Combination of Ombitasvir and Paritaprevir-Ritonavir.

The two direct-acting antiviral (2D) regimen of ombitasvir and paritaprevir (administered with low-dose ritonavir) is being developed for treatment of genotype subtype 1b and genotypes 2 and 4 chronic hepatitis C virus (HCV) infection. Drug-drug interactions were evaluated in healthy volunteers to develop dosing recommendations for HCV-infected subjects. Mechanism-based interactions were evaluated for ketoconazole, pravastatin, rosuvastatin, digoxin, warfarin, and omeprazole. Interactions were also evaluated for duloxetine, escitalopram, methadone, and buprenorphine-naloxone. Ratios of geometric means with 90% confidence intervals for the maximum plasma concentration and the area under the plasma concentration-time curve were estimated to assess the magnitude of the interactions. For most medications, coadministration with the 2D regimen resulted in a <50% change in exposures. Ketoconazole, digoxin, pravastatin, and rosuvastatin exposures increased by up to 105%, 58%, 76%, and 161%, respectively, and omeprazole exposures decreased by approximately 50%. Clinically meaningful changes in ombitasvir, paritaprevir, or ritonavir exposures were not observed. In summary, all 11 medications evaluated can be coadministered with the 2D regimen, with most medications requiring no dose adjustment. Ketoconazole, digoxin, pravastatin, and rosuvastatin require lower doses, and omeprazole may require a higher dose. No dose adjustment is required for the 2D regimen.

[Mechanisms of action, pharmacology and interactions of dolutegravir]. / Mecanismo de acción, farmacología e interacciones de dolutegravir.

Dolutegravir is a second-generation integrase strand transfer inhibitor (INSTI), whose potential and binding half-life in the integrase are far superior to those of raltegravir and elvitegravir, conferring it with unique characteristics in terms of its genetic barrier to resistance and activity against viruses with one or more mutations in the integrase. The pharmacokinetic properties of dolutegravir allow once-daily dosing (50 mg), with or without food, maintaining concentrations far above those effective against wild-type viruses. If integrase resistance mutations are present, the recommended dosing regimen is 50 mg/12 h. The distribution of dolutegravir in cerebrospinal fluid is good and effective concentrations are also reached in the male and female genital tracts. Dolutegravir is metabolized by UGT1A1 and, to a lesser extent, by CYP3A4, without being an inducer or inhibitor of the usual metabolic systems. It has a very low potential for drug interactions and can be administered in routine doses with most drugs. Dose adjustment is not required, even in patients with renal insufficiency or mild or moderate liver failure. Increasing the dose of dolutegravir (50 mg/12 h) is only recommended when administered with efavirenz, nevirapine, fosamprenavir/r, tipranavir/r, rifampicin, carbamazepine, phenytoin and phenobarbital. Coadministration of dolutegravir with etravirine is not recommended without a protease inhibitor or with Hypericum perforatum. Dolutegravir should be administered 2 h before or 6 h after antacids or products with polyvalent cations. Dolutegravir can reduce renal tubule secretion of substances excreted via OCT2, with a slight initial increase in creatinine, with no risk of renal toxicity. The drug can also increase metformin concentrations and consequently monitoring is recommended in case dose adjustment is required. In summary, dolutegravir has excellent pharmacokinetic and drug interaction profiles.

Evaluation of the effect of orally administered acid suppressants on intragastric pH in cats.

BACKGROUND: Acid suppressant drugs are a mainstay of treatment for cats with gastrointestinal erosion and ulceration. However, clinical studies have not been performed to compare the efficacy of commonly PO administered acid suppressants in cats. HYPOTHESIS/OBJECTIVES: To compare the effect of PO administered famotidine, fractionated omeprazole tablet (fOT), and omeprazole reformulated paste (ORP) on intragastric pH in cats. We hypothesized that both omeprazole formulations would be superior to famotidine and placebo. ANIMALS: Six healthy adult DSH colony cats. METHODS: Utilizing a randomized, 4-way crossover design, cats received 0.88-1.26 mg/kg PO q12h fOT, ORP, famotidine, and placebo (lactose capsules). Intragastric pH monitoring was used to continuously record intragastric pH for 96 hours beginning on day 4 of treatment. Plasma omeprazole concentrations at steady state (day 7) were determined by high performance liquid chromatography (HPLC) with ultraviolet detection. Mean percentage time that intragastric pH was ≥ 3 and ≥ 4 were compared among groups using ANOVA with a posthoc Tukey-Kramer test (α = 0.05). RESULTS: The mean percentage time ± SD that intragastric pH was ≥ 3 was 68.4 ± 35.0% for fOT, 73.9 ± 23.2% for ORP, 42.8 ± 18.6% for famotidine, and 16.0 ± 14.2% for placebo. Mean ± SD plasma omeprazole concentrations were similar in cats receiving fOT compared to those receiving ORP and in a range associated with acid suppression reported in other studies. CONCLUSIONS AND CLINICAL IMPORTANCE: These results suggest that both omeprazole formulations provide superior acid suppression in cats compared to famotidine or placebo. Fractionated enteric-coated OT is an effective acid suppressant despite disruption of the enteric coating.

Neonatal seizures: soothing a burning topic.

Neonatal seizures are a potentially life-threatening pediatric problem with a variety of causes, such as birth trauma, asphyxia, congenital anomalies, metabolic disturbances, infections, and drug withdrawal or intoxication. Thorough and timely evaluations of such patients are necessary to identify and treat the underlying etiology, therefore reducing potential morbidity and mortality. We review neonatal seizures and hypocalcemia and present the case of a 6-day-old male infant who presented to a tertiary pediatric emergency department with seizure-like episodes. He was found to have markedly low serum calcium, magnesium, and parathyroid hormone concentrations, as well as a significantly elevated serum phosphate concentration. The etiology of these abnormalities was found to be maternal ingestion of extremely high doses of calcium carbonate during the third trimester of her pregnancy, an occurrence that has been reported only once in the literature. Education pertaining to the dangers of excessive calcium carbonate intake during pregnancy may be an important piece of anticipatory guidance for pregnant mothers with symptoms of gastroesophageal reflux, and questioning the mother of a neonate presenting with seizures about such over-the-counter medications may help to elucidate the diagnosis.

A study of the potential application of nano-Mg(OH)2 in adsorbing low concentrations of uranyl tricarbonate from water.

This work aims at the investigation of nano-Mg(OH)(2) as a promising adsorbent for uranium recovery from water. Systematic analysis including the uranium adsorption isotherm, the kinetics and the thermodynamics of adsorption of low concentrations of uranyl tricarbonate (0.1-20 mg L(-1)) by nano-Mg(OH)(2) was carried out. The results showed a spontaneous and exothermic uranium adsorption process by Mg(OH)(2), which could be well described with pseudo second order kinetics. Surface site calculation and zeta potential measurement further demonstrated that UO(2)(CO(3))(3)(4-) was a monolayer adsorbed onto nano-Mg(OH)(2) by electrostatic forces. Accordingly, the adsorption behavior met the conditions of the Langmuir isotherm. Moreover, in most of the reported literature, nano-Mg(OH)(2) had a higher UO(2)(CO(3))(3)(4-) adsorption affinity b, which implied a higher adsorption amount at equilibrium in a dilute adsorbate system. The significance of the adsorption affinity b for choosing and designing adsorbents with respect to low concentration of resources/pollutants treatment has also been assessed.

Alginate-antacid combinations: raft formation and gastric retention studies.

BACKGROUND: Alginate-based gastroesophageal reflux disease treatments have been used extensively and fall into two main categories. Those containing alginate as the principle active agent and those containing alginate in combination with a significant amount of antacid. METHOD: The effectiveness of the raft formed by a new alginate/antacid suspension (Gaviscon Double Action Liquid, GDAL), in which calcium carbonate was the main antacid ingredient, was compared with those of existing alginate/antacid suspensions. RESULT: GDAL had similar raft strength and improved raft resilience than Gaviscon Liquid (GL), and both were significantly greater than five other products tested. Gastric retention of GDAL was similar to that of GL. CONCLUSION: the in vitro and in vivo performance is maintained in the new GDAL formulation even with higher antacid levels and the product is as good as, or better than, previous formulations.

[Efficacy of antacids in the treatment of chronic gastritis].

This article presents main principles of chronic gastritis treatment. Therapeutic abilities and possible side-effects due to components of antacids are analyzed. Special attention is paid to antisecretory and cytoprotective activity of Pepsan-R, which contains haiasulen (the main active component of chamomilla) and dimeticon. The authors of the article emphasize opportunity of using Pepsan-R in case of heartburn, gastric pain, abdominal distention during pregnancy and lactation.

Effect of food and antacids on the pharmacokinetics of pirfenidone in older healthy adults.

Pirfenidone is a small, synthetic molecule under investigation for treatment of idiopathic pulmonary fibrosis. In an open-label, single-dose crossover study, the pharmacokinetics (PK) of pirfenidone were investigated with or without food and antacids in healthy adult volunteers. Concentrations of pirfenidone and its metabolites in plasma and urine were determined by liquid chromatography with tandem mass spectrometry, and candidate pharmacokinetic models were fit to plasma data using weighted, non-linear regression. The effect of food and antacids on pirfenidone exposure was evaluated by determining 'equivalence' using FDA guidelines. Adverse events were recorded by site personnel and classified by investigators on the basis of severity and relationship to study drug. Sixteen subjects yielded 64 pharmacokinetic profiles. The best fit was achieved using a five-compartment, linear model with an allowance for direct conversion to the primary metabolite (5-carboxy-pirfenidone). Coadministration with food decreased the rate and, to a lesser degree, the extent of pirfenidone absorption of absorption. Analysis of adverse events revealed a correlation between pirfenidone C(max) and the risk of gastrointestinal (GI) adverse events, suggesting that food may reduce the risk of certain adverse events associated with pirfenidone. Administration of pirfenidone with food has a modest effect on overall exposure but results in lower peak concentrations, which may improve tolerability.

Oxethazaine as the source of mephentermine and phentermine in athlete's urine.

The urine specimens of numerous athletes were found to be positive for mephentermine both in-competition and out-of-competition in Taiwan. The donor of one specimen claimed she had only taken Mucaine (contains oxethazaine) for relieving symptomatic peptic ulcer and gastritis. Oxethazaine is not included in the prohibited list of the World Anti-Doping Agency; however, its metabolized compounds, mephentermine and phentermine, are included in that list. This study applied LC-MS-MS to analyze the excretions of three volunteers who ingested oxethazaine and presented positive results for mephentermine and/or phentermine. Thus, oxethazaine is the source of mephentermine and phentermine. Moreover, the results showed that 48 brands of gastric medicines containing oxethazaine were legally imported or locally manufactured in Taiwan, information which could be useful for limiting the misuse of oxethazaine by athletes. The data suggested that the sports associations should warn athletes about the risks of taking oxethazaine.

Body mass index and the efficacy of acid-mediating agents for GERD.

In studies of the association between obesity and gastroesophageal reflux, one subject that has received very little attention is the effect excess body mass may have on the effectiveness of acid-mediating agents. The lack of systematic research may reflect the perceived high clinical efficacy of drugs like proton pump inhibitors. Both proton pump inhibitors and histamine type 2 receptor antagonists have low rates of significant adverse events; if there are differences in the side effect profiles based on BMI, it is unlikely such associations would be detected. Also, while the metabolism of many drugs can be affected by body mass, it is not clear that such a relationship exists with acid-mediating agents. Nevertheless, there is evidence that body mass index may indeed be associated with the efficacy of proton pump inhibitors and histamine type 2 receptor antagonists. This review will examine that evidence and consider some of the possible pharmacokinetic effects that might relate to body mass index.