Profiling gene expression dynamics underpinning conventional testing approaches to better inform pre-clinical evaluation of an age appropriate spironolactone formulation.

There is a need to accelerate paediatric formulation evaluation and enhance quality of early stage data in drug development to alleviate the information pinch point present between formulation development and clinical evaluation. This present work reports application of DNA microarrays as a high throughput screening tool identifying markers for prediction of bioavailability and formulation driven physiological responses. With a focus on enhancing paediatric medicine provision, an oral liquid spironolactone suspension was formulated addressing a paediatric target product profile. Caco-2 cells cultured on transwell inserts were implemented in transport assays in vitro and DNA microarrays were used to examine gene expression modulation. Wistar rats were used to derive in vivo bioavailability data. In vitro, genomic, and in vivo data sets were concurrently evaluated linking drug transport and the genomic fingerprint generated by spironolactone formulation exposure. Significant changes in gene expression are reported as a result of formulation exposure. These include genes coding for ATP-binding cassette (ABC) transporters, solute carrier (SLC) transporters, cytochrome P450 (CYP) enzymes, and carboxylesterase enzymes. Genomic findings better inform pre-clinical understanding of pharmacokinetic and pharmacodynamic responses to spironolactone and its active metabolites than current in vitro drug transport assays alone.

Vanillin enhances the passive transport rate and absorption of drugs with moderate oral bioavailability in vitro and in vivo by affecting the membrane structure.

Vanillin is a popular flavoring agent in the food, tobacco, and perfume industries. In this paper, we investigated the effect of vanillin on the transport rates of drugs with different levels of permeability (acyclovir, hydrochlorothiazide, propranolol and carbamazepine) through a Caco-2 cell bidirectional transport experiment. We also explored the underlying mechanism using an in silico technique and fluorescence anisotropy measurements. The influence of vanillin on the pharmacokinetics of drugs whose transport rates were affected by vanillin in vitro was then studied in vivo. Results showed that vanillin (100 µM) increased the cumulative amount of passively transported drugs (2.1-fold of hydrochlorothiazide, 1.49-fold of propranolol, 1.35-fold of acyclovir, and 1.34-fold of carbamazepine) in vitro. Molecular dynamics simulations revealed that vanillin disordered the structure of the lipid bilayer and reduced the energy barrier of drugs across the center of the membrane. The anisotropy of TMA-DPH also decreased in Caco-2 cells after treatment with vanillin (25 and 100 µM) and indicated an increase in membrane fluidity, which was dose-dependent. An oral bioavailability study indicated that vanillin (100 mg kg-1) significantly enhanced the Cmax and AUC0-6 of hydrochlorothiazide by 1.42-fold and 1.28-fold, respectively, and slightly elevated the Cmax of propranolol. In conclusion, vanillin can significantly increase the absorption of drugs with moderate oral bioavailability in vitro and in vivo by loosening the membrane. Thus, the concurrent consumption of drugs with food containing vanillin may result in increased drug plasma concentration and pose potential health risks.

Evaluation of diuretic and laxative activity of aqueous extract of Argemone mexicana leaves in rats / Evaluación de la actividad diurética y laxante del extracto acuoso de hojas de Argemone mexicana en ratas

Objectives: Argemone mexicana have been widely studied for its several pharmacological benefits and has been used in traditional medicine to treat constipation like symptoms. The present study carried out to evaluate the extract for its diuretic and laxative potential. Method: The aqueous extract of Argemone mexicana prepared using percolation method and subjected to phytochemical analysis. Evaluation of diuretic and laxative activity was carried out using metabolic cage apparatus and flame photometer as per the standard method reported earlier. Frusemide (20 mg/ kg) and sodium picosulate (5 mg/kg) were served as positive control for diuretic activity and laxative activity respectively. Result: The extract showed significant diuretic activity at 250 mg/kg dose when compared to standard frusemide. Even this extract also effective in increasing electrolyte concentration. Whereas the extract at 250 mg/kg showed significantly increasing in fecal output, and also significantly increased the weight of feces at 100 mg/kg and 200 mg/kg dose. Conclusion: The previous significant finding supports the traditional use of Argemone mexicana for its diuretic and laxative potential

Objetivos: Argemone mexicana ha sido ampliamente estudiada por sus diversos beneficios farmacológicos y se ha utilizado en la medicina tradicional para tratar síntomas de estreñimiento. El presente estudio evaluó el extracto por su potencial diurético y laxante. Método: El extracto acuoso de Argemone mexicana se preparó utilizando el método de percolación y se sometió a análisis fitoquímico. La evaluación de la actividad diurética y laxante se llevó a cabo utilizando unas jaulas metabólicas y un fotómetro de llama según el método estándar descrito con anterioridad. Se administró frusemida (20 mg / kg) y picosulato de sodio (5 mg / kg) como control positivo de la actividad diurética y actividad laxante respectivamente. Resultado: El extracto mostró una actividad diurética significativa a una dosis de 250 mg / kg en comparación con la frusemida estándar. Incluso, este extracto también es efectivo para aumentar la concentración de electrolitos. Mientras que el extracto a 250 mg/kg mostró un aumento significativo en la producción fecal, y también aumentó significativamente el peso de las heces en ambas dosis. Conclusión: El hallazgo significativo anterior apoya el uso tradicional de Argemone mexicana por sus potencialidades diurética y laxante

Phytochemical Screening and Acute Oral Toxicity Study of Java Tea Leaf Extracts.

The term Java tea refers to the decoction of Orthosiphon stamineus (OS) Benth (Lamiaceae) leaves, which are widely consumed by the people in Europe and South East Asian countries. The OS leaves are known for their use in traditional medicinal systems as a prophylactic and curative agent for urinary stone, diabetes, and hypertension and also as a diuretic agent. The present study was aimed at evaluating its possible toxicity. Herein, the major phytochemical constituents of microwave dried OS leaf, which is the common drying process for tea sachets in the market, were also identified. The acute oral toxicity test of aqueous, 50% aqueous ethanolic, and ethanolic extracts of OS was performed at a dose of 5000 mg/Kg body weight of Sprague-Dawley rats. During the 14-day study, the animals were observed for any mortality, behavioral, motor-neuronal abnormalities, body weight, and feed-water consumption pattern. The hematological and serum biochemical parameters to assess the kidney and liver functions were carried out, along with the histological analysis of these organs. It was found that all microwave dried OS leaf extracts did not cause any toxic effects or mortality at the administered dose. No abnormality was noticed in all selected parameters in rats of both sexes as compared with their respective control groups. Thus, the possible oral lethal dose for microwave dried Java tea leaves is more than 5000 mg/Kg body weight.

Risk of hypercalcemia in blacks taking hydrochlorothiazide and vitamin D.

INTRODUCTION: Hydrochlorothiazide, an effective antihypertensive medication commonly prescribed to blacks, decreases urinary calcium excretion. Blacks have significantly higher rates of hypertension and lower levels of 25-hydroxyvitamin D. Thus, they are more likely to be exposed to vitamin D supplementation and thiazide diuretics. The risk for hypercalcemia among blacks using vitamin D and hydrochlorothiazide is undefined. METHODS: We assessed the frequency of hypercalcemia in hydrochlorothiazide users in a post hoc analysis of a randomized, double-blind, dose-finding trial of 328 blacks (median age 51 years) assigned to either placebo, or 1000, 2000, or 4000 international units of cholecalciferol (vitamin D3) daily for 3 months during the winter (2007-2010). RESULTS: Of the 328 participants, 84 reported hydrochlorothiazide use and had serum calcium levels assessed. Additionally, a comparison convenience group of 44 enrolled participants who were not taking hydrochlorothiazide had serum calcium measurements at 3 months, but not at baseline. At 3 months, hydrochlorothiazide participants had higher calcium levels (0.2 mg/dL, P <.001) than nonhydrochlorothiazide participants, but only one participant in the hydrochlorothiazide group had hypercalcemia. In contrast, none of the nonhydrochlorothiazide participants had hypercalcemia. In a linear regression model adjusted for age, sex, 25-hydroxyvitamin D at 3 months, and other covariates, only hydrochlorothiazide use (Estimate [SE]: 0.05 [0.01], P = .01) predicted serum calcium at 3 months. CONCLUSION: In summary, vitamin D3 supplementation up to 4000 IU in hydrochlorothiazide users is associated with an increase in serum calcium but a low frequency of hypercalcemia. These findings suggest that participants of this population can use hydrochlorothiazide with up to 4000 IU of vitamin D3 daily and experience a low frequency of hypercalcemia.

The effective method for investigation meridian tropism theory in rats.

This present work describes an effective new method for study traditional Chinese medicine (TCM) on meridian tropism (MT) theory, which plays an essential role in clinical selection of TCM according to syndromes and strengthens the therapeutic effects. The new thread included material basis foundation and its tissue distribution study. Xiheliu, the most popular TCM on heart tropism, was investigated by simple and accurate high performance liquid chromatography (HPLC) method. The analysis of plasma after oral administration the total flavonoid of Xiheliu (TFX) exhibited that tamarixetin and kaempferide had the highest concentration and approximately the highest level within 25 min. The mixture of them could last accelerating the urine excretion more than 7 h after a single dose and could not cause the disorder of ion in rats, which was observed in diuretic activity experiment. In view of the reported biological activities was consistent with the effects of Xiheliu, tamarixetin and kaempferide were likely to be the material basis of it. Tissue distribution study showed that the highest level of analytes was in heart, lung, kidney and liver, and most tissues reached maximum level at 30 min post-dose. Since liver was the most important blood-supply tissue, the result of this experiment was in accordance with the MT record of Xiheliu and confirmed that tamarixetin and kaempferide was the material bases of it on MT. This is the first report for the illumination of material basis and the mechanism of Xiheliu on MT by analysis the record of Xiheliu in Compendium of Materia Medica and experimental study.

Are all diuretics equal for the treatment of hypertensive patients?

Thiazide (hydrochlorothiazide, etc.) and thiazide-like (chlortalidone, indapamide,etc.) diuretics are widely used to treat hypertensive patients. There is growing evidence that these diuretics are not interchangeable and that it might be preferable to choose a thiazide-likediuretic whenever the use of a diuretic is considered. This is in order to prevent optimally the development of cardiovascular complications and the occurrence of metabolic side effects, in particular diabetes (AU)

Las tiazidas (hidroclorotiazida, etc.) y los diuréticos de tipo tiazídico (clortalidona,indapamida, etc.) son fármacos ampliamente utilizados para tratar la hipertensión. Existe pruebas crecientes de que estos diuréticos no son intercambiables y sería preferible elegir un diurético de tipo tiazídico siempre que se considere el uso de los mismos. La razón para ello es evitar de manera óptima el desarrollo de complicaciones cardiovasculares y la aparición de efectos secundarios metabólicos, en particular la diabetes (AU)

Development and evaluation of a chronotherapeutic drug delivery system of torsemide / Desenvolvimento e avaliação de um sistema de entrega de drogas cronoterapêuticas de torsemida

The objective of this study was to prepare and evaluate chronotherapeutic drug delivery systems (ChrDDs) of torsemide. Compression coated tablets (CCT) containing torsemide in the core tablet were prepared by the compression coating technique with different grades of polyethylene oxide (PEO WSR 301 & 1105). The optimized formulations were characterised for tabletting parameters and drug polymer interaction by Fourier-Transform Infrared Spectroscopy (FTIR).The hardness of all the CCT using PEO WSR 301 & PEO WSR 1105 were in the range 6-8 kg/cm² & 5.5 to 7 kg/cm² respectively. Their friability values were <0.3 percent. All the CCT showed a clear lag time but finalized as per the predetermined lag time. As the amount of PEO was increased in the outer layer the drug released was delayed. The drug content of all the CCT was >99 percent. The FTIR studies showed no interaction throughout the process of development. Formulations of F7 and of P7 were considered optimized formulations since they yielded a predetermined lag time of 6h before burst release. Hence, these formulations can be exploited to achieve chronotherapeutic drug delivery systems of Torsemide for the treatment of hypertension at the time the patient needs it.

O objetivo deste estudo foi preparar e avaliar sistemas cronoterapêuticos de liberação de fármacos (ChrDDs) de torsemida. Comprimidos revestidos por compressão (CCT) contendo torsemida no (núcleo) foram preparados pela técnica de revestimento por compressão, com diferentes categorias de óxido de polietileno (PEO WSR 301 & 1105). As formulações otimizadas foram caracterizadas por parâmetros de compressão e interação fármaco polímero por Infravermelho com Transformada de Fourier (FTIR). A dureza dos CCT utilizando PEO WSR 301 e PEO WSR 1105 foi entre 6-8 kg/cm² e 5,5 a 7 kg/cm², respectivamente. Os valores de friabilidade foram <0,3 por cento. Todos os CCT mostraram claro tempo de retardo, mas finalizaram de acordo com o tempo de retardo pré-determinado. À medida que a quantidade de PEO aumentava na camada mais externa, a liberação do fármaco era retardada. O teor de fármaco em todos os CCT foi >99 por cento. Os estudos de FTIR mostraram que não h[a interação durante o processo de desenvolvimento. As formulações F7 e P7 foram consideradas otimizadas, uma vez que resultaram em tempo de retardo pré-determinado de 6 h antes da liberação por meio de explosão. Dessa forma, estas formulações podem ser exploradas para se obter sistemas de liberação.

Detection of bumetanide in an over-the-counter dietary supplement.

Bumetanide is a loop diuretic used clinically to treat heart failure, acute renal failure, high blood pressure, and edema. However, diuretics may also be used by athletes as masking agents and to decrease weight. Taken as masking agents, diuretics increase urine production and decrease urinary concentrations of banned performance-enhancing agents, such as anabolic steroids. StarCaps is an over-the-counter dietary supplement marketed as a diet aid. The manufacturer claims that the product contains only natural cleansing agents and emphasizes that it is free from traditional appetite suppressants such as sympathomimetic amines. However, no such disclaimer is made concerning diuretic agents. A single StarCaps capsule was administered to two male and two female volunteers, and their urine specimens were collected at discrete intervals (2, 4, 8, and 12 h) post administration. The specimens were analyzed by a high-performance liquid chromatography-mass spectrometry quadrupole (HPLC-MS) method, and bumetanide was detected in all specimens (4.6 to 351.3 ng/mL). Adjusting the bumetanide concentrations for creatinine content did little to normalize the excretion profiles. Bumetanide was also detected in the StarCaps capsules at concentrations approaching therapeutic doses. HPLC-quadrupole-time-of-flight mass spectrometry was used to confirm the presence of bumetanide in the urine samples and StarCaps capsules. The results showed that unregulated dietary supplements may put consumers at risk for unwitting consumption of prescription medications, and that it is possible for athletes to inadvertently test positive for bumetanide and face disciplinary actions.

Cronoterapia con torasemida en pacientes hipertensos: aumento de la duración y la eficacia terapéuticas con su administración a la hora de acostarse / Chronotherapy with torasemide in hypertensive patients: increased efficacy and therapeutic coverage with bedtime administration

Fundamento y objetivo: La torasemida es un diurético de asa utilizado con frecuencia en el tratamiento de la insuficiencia cardíaca, la insuficiencia renal y la hipertensión, en función de resultados basados, sobre todo, en la medida clínica de la presión arterial, sin que se haya valorado la eficacia y la duración del fármaco durante las 24 h. Por ello, hemos investigado la eficacia antihipertensiva y los efectos de la torasemida en el perfil circadiano de la presión arterial, administrada a distintas horas en función del ciclo de actividad y descanso. Pacientes y método: Estudiamos a 58 pacientes hipertensos (25 varones y 33 mujeres) con una media (DE) de edad de 48,7 (11,9) años, asignados aleatoriamente a 2 grupos de tratamiento en función del momento de tomar una dosis de 5 mg/día de torasemida: a la hora de levantarse o a la hora de acostarse. La presión arterial se determinó ambulatoriamente durante 48 h consecutivas antes y después de 6 semanas de intervención terapéutica. Resultados: La eficacia de la torasemida fue mayor con la dosis nocturna (11,2 y 8,0 mmHg en la media de 24 h de la presión arterial sistólica y diastólica, respectivamente) que con la matutina (6,2 y 3,7 mmHg de presión sistólica y diastólica). El porcentaje de pacientes con presión arterial ambulatoria controlada fue el doble cuando se administró la torasemida a la hora de acostarse (54%) que cuando se la administró a la hora de levantarse (27%). La duración de la eficacia terapéutica se mantuvo a lo largo de las 24 h sólo cuando se administró la torasemida a la hora de acostarse. Con respecto al perfil de seguridad, 2 pacientes presentaron efectos secundarios (dolor abdominal, diarrea) con la toma matutina y 4 con la nocturna (nicturia). Conclusiones: Una dosis de 5 mg/día de torasemida en monoterapia reduce de forma eficaz la presión arterial cuando se administra el fármaco a la hora de acostarse. Se debe tener en cuenta las diferencias en la eficacia antihipertensiva, la duración del efecto terapéutico y el grado de control en función de la hora de tomar la torasemida cuando se prescriba este diurético de asa en el tratamiento de pacientes con hipertensión arterial esencial

Background and objective: Torasemide is a high ceiling loop diuretic frequently used for treatment of heart failure, renal failure and hypertension, according to results mainly based on clinic blood pressure measurements, without proper evaluation of the 24-hour efficacy of the drug. Accordingly, we investigated the time-dependent antihypertensive efficacy of torasemide in hypertensive patients. Patients and method: We studied 58 patients with grade 1-2 essential hypertension (25 men and 33 women), 48.7 (11.9) years of age, randomly assigned to receive torasemide (5 mg/day) either upon awakening or at bedtime. Blood pressure was measured by ambulatory monitoring for 48 consecutive hours before and after 6 weeks of therapy. Results: Efficacy of torasemide was significantly higher with bedtime dosing (11.2 and 8.0 mmHg reduction in the 24-hour mean of systolic and diastolic blood pressure, respectively) as compared to the administration of the drug on awakening (6.2 and 3.7 mmHg reduction in systolic and diastolic blood pressure). The percentage of patients with controlled ambulatory blood pressure after treatment was also higher after bedtime treatment (54% versus 27%). The time-response curves indicate a full 24-hour therapeutic duration only when torasemide was administered before bedtime. With regard to the safety profile, 2 patients presented secondary effects (abdominal pain, diarrhea) in morning dose, and 4 patients taking the drug at bedtime reported nicturia. Conclusions: A dose of 5 mg/day torasemide is effective for blood pressure reduction after bedtime administration. The differences in efficacy and therapeutic duration as a function of the circadian time of treatment with torasemide here documented should be taken into account when prescribing this loop diuretic for treatment of patients with essential hypertension

Effects of cysteine on the pharmacokinetics and pharmacodynamics of intravenous and oral azosemide in rats with protein-calorie malnutrition.

The effects of cysteine on the pharmacokinetics and pharmacodynamics of azosemide were investigated after intravenous (10 mg/kg) and oral (20 mg/kg) administration to male Sprague-Dawley rats fed on 23% protein diet (control rats), and 5% protein diet with (rats with PCMC) or without (rats with PCM) oral cysteine (250 mg/kg, twice daily for the fourth week) for 4 weeks. After intravenous administration to rats with PCMC, some pharmacokinetic parameters restored fully or more than the level of control rats; the time-averaged nonrenal clearance (2.70 versus 2.32 ml/min/kg) and apparent volume of distribution at steady state (160 versus 189 ml/kg) were comparable to those in control rats, however, the terminal half-life (34.7 versus 57.2 min) and mean residence time (73.3 versus 99.3 min) were significantly shorter, area under the plasma concentration-time curve from time zero to time infinity (AUC, 1930 versus 2680 microg min/ml) was significantly smaller, and time-averaged renal (2.24 versus 1.21 ml/min/kg) and total body (CL, 4.98 versus 3.65 ml/min/kg) clearances were significantly faster than those in control rats. This could be mainly due to significantly faster renal clearance and at least partly due to increased cytochrome P450 1A2 activity by cysteine supplementation. After intravenous administration to rats with PCMC, the total amount of 8-hr urinary excretion of unchanged azosemide was significantly greater (457 versus 305 microg/g body weight), however, the 8-hr urine output (15.3 versus 31.1 ml/g kidney) was not significantly different between control rats and rats with PCMC. This could be due to the fact that urine output seemed to reach an upper plateau from 10 mg/kg dose of azosemide in rats.

[Diuretic activity of the infusion of flowers from Lavandula officinalis]. / Effet diurétique de l'infusion de fleurs de Lavandula officinalis. [Diuretic activity of the flowers infusion of Lavandula officinalis.

The diuretic activity of an infusion of Lavandula officinalis was studied in the Wistar rat. Thus, the kinetics of hydroelectrolytic elimination in response to the oral administration of an infusion of pharmaceutical lavender flowers were measured in the rats. Experiments were completed under similar conditions using a synthetic pharmacological diuretic, Diamox. The aqueous extract of this aromatic plant accelerated the elimination of the water overload. At the peak of the diuretic response, urinary osmolarity was significantly less than that of controls (111+/-14 vs. 195+/-11 mosmol x kg(-1)). Sodium excretion was moderate following administration of the infusion when compared to the synthetic diuretic. The stability of the aldosterone concentrations in the plasma and the absence of correlation with plasma sodium concentrations, coupled with the observed clearance of the free water (0.055+/-0.007 vs. 0.045+/-0.012 mL x min(-1)) show that the increase in diuresis and the moderate increase in sodium excretion are of tubular origin. The result of the phytochemical analysis of hexane extracts in the infusion and in urine indicated that four or five chemical factors may be involved in the diuretic effect of lavender.

Suppression of rat hepatic cytochrome P450s by protein-calorie malnutrition: complete or partial restoration by cysteine or methionine supplementation.

Pharmacokinetic profiles of therapeutic agents are altered by protein-calorie malnutrition (PCM). The current study was designed to determine the expression of hepatic cytochrome P450s in rats after protein restriction and to investigate its molecular basis. Western blot analysis revealed that rats with protein restriction for 4 weeks exhibited marked suppression in the hepatic P450 1A2, 2C11, 2E1, and 3A1/2 levels. Northern blot analysis showed that hepatic P450 1A2, 2C11, and 3A1/2 mRNAs were significantly decreased in the state of PCM. The P450 2E1 mRNA level was slightly decreased in PCM rats, suggesting the possibility that expression of P450 2E1 affected by PCM might result from the transcriptional and/or posttranscriptional regulation. PCM-induced changes in most P450 expression completely or partially returned to control levels by a week of cysteine supplementation. Cysteine also prevented decreases in P450 1A2, 2C11, 2E1, and 3A1/2 mRNA levels by PCM. Methionine was minimally active in restoring the P450 expression. A metabolic change in hepatic ethoxyresorufin dealkylase activity in PCM rats was consistent with the P450 apoprotein and mRNA levels. Although the plasma concentrations of azosemide, a loop diuretic, primarily metabolized by cytochrome P450 1A, increased in protein-deprived rats, cysteine supplementation significantly reduced the increased plasma concentrations of the drug. The altered pharmacokinetic parameters of azosemide in PCM rats returned to those of control after cysteine supplementation, corroborating the conclusion that cysteine was effective in restoring cytochrome P450 expression and metabolic activities.

Water-soluble beta-cyclodextrins in paediatric oral solutions of spironolactone: preclinical evaluation of spironolactone bioavailability from solutions of beta-cyclodextrin derivatives in rats.

Water-soluble derivatives of beta-cyclodextrin have been considered for solubilization of spironolactone in the formulation of a safe liquid preparation for premature infants. The oral absorption of spironolactone was studied in rats to evaluate the need to adjust spironolactone dosage in prospective clinical studies. Spironolactone was administered in solutions of sulphobutyl ether beta-cyclodextrin (SBE7) or dimethyl-beta-cyclodextrin (DM-beta-CyD) and also as spironolactone-containing powder papers (reference preparation). Spironolactone in SBE7 solution was administered intravenously to assess the extent of intestinal absorption from the different formulations. Spironolactone and the metabolites 7alpha-thiospirolactone, 7alpha-thiomethylspirolactone and canrenone were determined in rat serum after intravenous administration of spironolactone. Half-lives for spironolactone, 7alpha-thiomethylspirolactone and canrenone were 0.72 +/- 0.17, 1.5 +/- 0.3 and 2.2 +/- 0.3 h, respectively. Although, according to Cmax values, 7alpha-thiomethylspirolactone was the major serum metabolite in rats, higher AUC (area under the serum concentration-time curve) values were obtained for canrenone. After oral administration of spironolactone the bioavailabilities evaluated from the AUC values of 7alpha-thiomethylspirolactone were 27.5 +/- 9.3%, 81.3 +/- 28.8% and 82.8 +/- 28.6% for powder papers, DM-beta-CyD and SBE7 solutions, respectively. The oral absorption of spironolactone by rats was better after administration of spironolactone in SBE7 and DM-beta-CyD solutions than after administration as powder papers. Both cyclodextrin formulations enhanced spironolactone bioavailability to a similar extent despite some deacetylation of spironolactone in the presence of SBE7. A reduction of spironolactone dosage would be recommended during clinical studies with premature infants. These results indicate that SBE7 could be a safe and suitable excipient for the solubilization of spironolactone in paediatric formulations.

Approaches to diuretic therapy and electrolyte imbalance in congestive heart failure.

This review has summarized the current role of diuretic therapy in heart failure, emphasizing those aspects most relevant to this patient population. Recommended diuretic usage is as follows: Asymptomatic left ventricular dysfunction--establish moderate sodium intake, Mild sodium retention--thiazide-type diuretic or low-dose loop diuretic; continue moderate sodium intake; combine with an ACE inhibitor, Moderate sodium retention--loop diuretic, adjusting for renal function, if necessary; continue moderate sodium intake; combine with an ACE inhibitor, Severe sodium retention--large-dose loop diuretic combined with a thiazide-type diuretic; continue moderate sodium intake; ACE inhibitor, unless contraindicated; consider addition of a potassium-sparing diuretic Treatment measures for refractory sodium retention--intermittent intravenous loop diuretic; short-term infusion of a loop diuretic; intensified combination oral diuretic therapy; intravenous positive inotropic therapy; ultrafiltration or dialysis. In addition, the well-known adverse effect of electrolyte depletion and guidelines for electrolyte replacement have been discussed. It is evident that the diuretic class of pharmacologic therapy has not been as well assessed as both the positive inotrope and vasodilator classes. Limitations in this regard have been summarized recently. Even relatively simple parameters or instruments, such as the sodium retention score, when applied to clinical trials will yield a greater understanding of the utility and limitations of diuretic therapy for heart failure.

Use of renal artery infusion in dogs for evaluation of diuretics.

In this paper we report on a series of experiments evaluating a model of renal artery infusion (RAI) as a screening technique for comparison of new diuretics, and test some assumptions underlying its use. The femoral artery and vein of Beagle dogs were catheterized for the infusion of solutions, measurement of arterial blood pressure and the sampling of arterial blood. The left kidney was isolated through a flank incision, and a 27 ga. needle, connected to PE10 tubing, was inserted into the renal artery for administration of test diuretics. Both ureters were catheterized for collection of urine. Effects on renal function were assessed during control, drug infusion, and recovery periods. At low doses, the loop diuretics, furosemide (FUR) and MK447, increased urinary excretion within the first 15 min of infusion. The effect of muzolimine, another loop diuretic, was delayed until about 45 min after initiation of infusion. Renal function returned to baseline after cessation of drug infusion. At high doses, excretion was increased by all the loop diuretics within the first 15 min of infusion. The response to muzolimine and MK447 was prolonged well into the recovery period, while that to furosemide returned promptly to baseline. Two distal diuretics, hydrochlorothiazide and amiloride, caused a significant increase in urinary excretion at both low and high doses. The magnitude of the response was significantly less than for the loop diuretics. Low doses of the loop diuretics had very little effect on the contralateral kidney; however, at high doses the excretion rate of the contralateral kidney was significantly increased.(ABSTRACT TRUNCATED AT 250 WORDS)