Improved bioavailability and clinical response in patients with chronic liver disease following the administration of a spironolactone: β-cyclodextrin complex

Aims To compare the absorption and clinical effect of spironolactone from an inclusion complex with β-cyclodextrin (SP-COMP) to Aldactone tablets (ALD) in chronic liver disease.
Methods Patients, admitted with chronic liver disease, completed a randomized crossover steady state study. They received their spironolactone dose as either daily SP-COMP or ALD for 7 days. Serial blood samples were drawn over a 24  h period from day 7 of each therapy. Accurate fluid balance was recorded on days 5–7 and 12–14. Thirteen (six females) whose mean (s.d.) age and weight was 58.4(9.3) years and 74.3(19.0)  kg completed the study.
Results The mean (95% confidence limits) relative bioavailability for SP-COMP (compared with ALD) from steady state serum concentrations of canrenone, 6β-hydroxyl 7α-thiomethyl spironolactone and 7α-thiomethyl spironolactone was 310.0 (265.4, 336.7), 233.4(212.9, 250.8) and 254.8(230.8, 279.0)%, respectively. Improvements in clinical status and fluid balance occurred over the last 3 days of SP-COMP with a mean (s.d.) net loss, in fluid balance, of 1370(860)ml compared with a gain of 228(936)ml during ALD.
Conclusions Better absorption of spironolactone from the spironolactone: β-cyclodextrin complex formulation should lead to a reduction in dosage and perhaps a more consistent effect in patients with chronic liver disease.     

Nitroreductases and glutathione transferases that act on 4-nitroquinoline 1-oxide and their differential induction by butylated hydroxyanisole in mice.

These studies concern the initial steps in 4-nitroquinoline 1-oxide (4NQO) metabolism in relation to mechanisms of anticarcinogenesis. Butylated hydroxyanisole (BHA) administration by a protocol known to inhibit the pulmonary tumorigenicity of 4NQO in A/HeJ mice enhanced hepatic and pulmonary activities for 4NQO metabolism by two major pathways, conjugative detoxification and nitroreductive activation. High-performance liquid chromatography analysis showed approximate doubling of two types of glutathione transferase subunits with 4NQO-conjugating activity in livers of BHA-treated mice. Similar increases were observed in hepatic 4NQO-conjugating activity and in Vmax, while Km for 4NQO was 39 to 43 microM. Pulmonary 4NQO-glutathione transferase activity increased 24 to 29%. DT diaphorase activity toward 4NQO was elevated 3.3-fold in livers and 2.7-fold in lungs of BHA-treated mice. However, the predominant 4NQO reductase of liver and lung was dicumarol resistant, had a strong preference for NADH, and showed little if any response to BHA. This Mr 200,000 enzyme, partially purified from livers of Swiss mice, exhibited the stoichiometry of 2-NADH/4NQO expected for reduction of 4NQO to 4-hydroxyaminoquinoline 1-oxide. Its high affinity for 4NQO (Km, 15 microM) signified a much greater influence on 4NQO metabolism than DT diaphorase (Km, 208 microM). The dicumarol-resistant 4NQO reductase differed from several known cytosolic nitroreductases. The results suggest that protection by BHA may result from alteration of the balance between 4NQO activation and conjugation.     

Implementing a family presence protocol option.

Families' needs of patients being resuscitated in critical care areas are frequently not a high priority for the healthcare team. However, recent research suggests family member presence during life-saving efforts may help families cope with the devastating outcomes of unsuccessful resuscitation. This article provides the rationale and process for implementing a family presence option during resuscitation.     

Central glucocorticoid regulation of parasympathetic drive to pancreatic B-cells in the obese fa/fa rat

The effects of glucocorticoids on the insulin secretory response to an intravenous glucose load have been studied in lean (Fa/?) and obese fa/fa Zucker rats. The role of parasympathetic drive to the pancreatic B-cells was assessed as that component of the insulin secretory response that was blocked by pretreatment of the rats with intravenous atropine. The insulin secretory response to the glucose load was greater in obese than in lean rats. Atropine significantly reduced basal and stimulated levels of insulin in obese but not in lean rats. Adrenalectomy reduced basal insulin levels and the secretory response in obese but not lean rats and also abolished the atropine-blockable component of the response. Peripheral corticosterone replacement of adrenalectomized fa/fa rats restored the hyperinsulinemia. Chronic infusion of dexamethasone intracerebroventricularly to adrenalectomized fa/fa rats increased basal insulin and the secretory response to glucose and this effect was blocked by atropine. In contrast, intracerebroventricular infusion of obese rats with corticotropin releasing factor reduced basal and stimulated insulin levels. It is concluded that the hypersecretion of insulin in obese fa/fa rats results, at least in part, from a central glucocorticoid-mediated stimulation of vagal drive to the pancreatic B-cells.     

Pneumothorax and other lung diseases: effect of altered resolution and edge enhancement on diagnosis with digitized radiographs

Prior studies have shown that pneumothorax is one of the more difficult entities to diagnose with digitized radiography. This study was designed to test whether increasing resolution from 1.25 to 2.5 line pairs per millimeter (lp/mm) and image processing (edge enhancement from unsharp masking) would increase accuracy and confidence in the diagnosis of pneumothorax, as well as normal cases and other forms of lung disease. Conventional radiographs were digitized with use of a laser reader and then reformatted as film hard copy. Eleven observers read 35 cases reformatted in three different ways (1.25 lp/mm, 2.5 lp/mm, 1.25 lp/mm unsharp mask). The images with finer resolution (2.5 lp/mm) and unsharp mask images were superior to those with coarser resolution (1.25 lp/mm) for the diagnosis of pneumothorax. There was no difference in diagnostic accuracy for normal patients. For abnormalities other than pneumothorax, the unsharp mask images were significantly worse. Confidence in the diagnosis of pneumothorax and other abnormalities was highest with the finest resolution (2.5 lp/mm).     

Investigation of an artificial intelligence technology--Model trees. Novel applications for an immediate release tablet formulation database.

This study has investigated an artificial intelligence technology - model trees - as a modelling tool applied to an immediate release tablet formulation database. The modelling performance was compared with artificial neural networks that have been well established and widely applied in the pharmaceutical product formulation fields. The predictability of generated models was validated on unseen data and judged by correlation coefficient R(2). Output from the model tree analyses produced multivariate linear equations which predicted tablet tensile strength, disintegration time, and drug dissolution profiles of similar quality to neural network models. However, additional and valuable knowledge hidden in the formulation database was extracted from these equations. It is concluded that, as a transparent technology, model trees are useful tools to formulators.     

Reformulation and drop size of apraclonidine hydrochloride.

We performed a prospective, double-masked, placebo-controlled, six-period, cross-over study in which normal subjects were randomly assigned to treatment and compared three different formulations of apraclonidine hydrochloride (the present commercially available formulation, and formulations with hydroxypropylmethylcellulose or lysolecithin). We also evaluated the efficacy of a 16-microliters and 30-microliters drop size. The magnitude and duration of decrease in intraocular pressure was comparable for all formulations. Most subjects tolerated all formulations well with only a few reporting any side effects. The best-tolerated formulation was 0.5% apraclonidine hydrochloride delivered with a 16-microliters drop size. Dry mouth developed frequently with the commercially available 1% apraclonidine solution. Blurred vision complicated the use of the formulation containing hydroxypropylmethylcellulose. Both dry mouth (P less than .05) and blurred vision (P = .004) were statistically significant side effects.