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At least 19 recordsLinked to original sources
PubMed1977

Quantitative determinations of codeine phosphate, guaifenesin, pheniramine maleate, phenylpropanolamine hydrochloride, and pyrilamine maleate in an expectorant by high-pressure liquid chromatography.

The quantitative determinations of codeine phosphate, guaifenesin, pheniramine maleate, phenylpropanolamine hydrochloride, and pyrilamine maleate in a liquid dosage form are described. All active and inactive ingredients (sodium benzoate and FD&C Yellow No. 5 dye) can be separated with high-pressure liquid chromatography except the two antihistamines, pheniramine maleate and pyrilamine maleate. Pheniramine maleate is determined colorimetrically, and pyrilamine maleate is determined either by difference or spectrophotometrically. The methods are simple short, accurate, and precise. The standard deviations are reported.

Chromatography, High Pressure Liquid↗
PubMed1978

Fluoremetric determination of methylergonovine maleate and ergonovine maleate in tablets and injections.

A column cleanup, followed by a shakeout and fluorometric determination, has been developed to determine methylergonovine maleate and ergonovine maleate in tablets and injections. The ether eluate is extracted with tartaric acid solution. An aliquot is diluted with sodium tartrate solution, and this solution is excited at 325 nm. The resulting fluorescence is measured at 432 nm. Results obtained using this method compare favorably with those from the official NF XIV procedure and a semiautomated procedure. Recoveries of 100 and 99% were obtained from one sample each of spiked excipient tablets of methylergonovine maleate and ergonovine maleate, respectively.

Ergonovine↗
PubMed1979

Semiautomated method for the analysis of formulations of chlorpheniramine maleate and brompheniramine maleate.

The determination of chlorpheniramine maleate and brompheniramine maleate in tablets, capsules, injections, and elixirs has been automated. The active ingredient is dissolved in dilute HCl. The dilute acid solution is sampled, made basic with dilute NaOH, and extracted with isooctane. The isooctane phase is resampled and the drug is re-extracted into dilute HCl. The absorbance of the acidic aqueous layer is monitored at 265 nm. The method is an automated version of the general USP XIX assay for salts of organic nitrogenous bases. The results from the semiautomated procedure agree well with the USP XIX and NF XIV official methods. Recoveries were 100% from an authentic tablet material. The system is linear from 0 to 300% of declared potency. The procedure is free from common excipient and dye interferences. Precision data are included for both the automated and official methods.

Autoanalysis↗
PubMed1975

Semiautomated analysis of ergonovine maleate or methylergonovine maleate tablets and injections by colorimetric or fluorometric systems.

Two semiautomated analytical systems have been developed to determine ergonovine and methylergonovine maleate in single tablets and injections. The active ingredient is dissolved in a tartrate buffer. In the fluorometric method the stream is automatically diluted with tartrate buffer and excited with ultraviolet light; the resulting fluorescence is measured and recorded. In the colorimetric method, the stream is automatically made basic with sodium hydroxide and extracted with n-butanol. The extract is mixed with p-dimethylaminobenzaldehyde reagent. After reaction, the solution is mixed with sodium nitrite solution, and the developed color is measured at 550 nm. Recoveries of 100% were obtained from spiked placebos. Standard deviations for powdered tablet and injection samples ranged from 0.63 to 1.24%. Comparisons with the USP XVIII methods are presented.

Autoanalysis↗
PubMed1976

Maleate-induced bicarbonaturia in the dog: a carbonic anhydrase-independene effect.

Studies were performed to characterize the renal effects of maleate in anesthetized dogs. Following the intravenous administration of maleate or maleic acid (50 mg/kg), mean fractional bicarbonate excretion (CHCO3/GFR) rose to as high as 26%. Na, K, and phosphate excretion also increased markedly, whereas C1 excretion remained low. An initial transient fall in urinary pH from 6.53 to 6.13 contrasted sharply with the rapid alkalinization of the urine induced by acetazolamide administration. During saline expansion CHCO3/GFR rose from 4 to 37% after maleate administration, whereas Cl excretion did not change significantly. During continuous carbonic anhydrase inhibition with acetazolamide, maleate administration resulted in a further rise in CHCO3/GFR from 22 to 35%. Whereas CPO4/GFR increased only from 1 to 3% during acetazolamide administration, this ratio reached 75% following the addition of maleate. Fumarate, the transisomer of maleate, and malonate, a well-known inhibitor of Krebs cycle, failed to affect bicarbonate excretion. This study demonstrates that maleate inhibits the fraction of bicarbonate reabsorption uncatalyzed by carbonic anhydrase. Impaired anionic reabsorption of bicarbonate or accelerated passive backflux of this ion into proximal tubular lumen are the two mechanisms that best explain the bicarbonaturia induced by maleate.

Acetazolamide↗
PubMed1975

Identity of maleate-stimulated glutaminase with gamma-glutamyl transpeptidase in rat kidney.

Gamma-Glutamyl transpeptidase was purified from rat kidney by a procedure involving Lubrol extraction, acetone precipitation, ammonium sulfate fractionation, treatment with bromelain, and column chromatography on DEAE-cellulose and Sephadex G-100. The final preparation (enzyme III), which exhibits a specific activity about 8-fold higher than that of the purified rat kidney transpeptidase previously obtained in this laboratory (enzyme I), was apparently homogeneous on polyacrylamide gel electrophoresis. Enzyme III is a glycoprotein containing 10% hexose, 7% aminohexose, and 1.5% sialic acid; a tentative molecular weight value of about 70,000 was obtained by gel filtration. Enzyme III has a much lower molecular weight and a different amino acid and carbohydrate content than the less active rat kidney transpeptidase preparation previously obtained, but obtained, but the catalytic properties of these preparations are virtually identical. It is suggested that bromelain treatment may liberate the transpeptidase from a brush border complex that contains other proteins. An improved method is described for the isolation of the higher molecular weight form of the enzyme (enzyme I) in which affinity chromatography on concanavalin A-Sephrose is employed. The purified transpeptidase (enzyme III) is similar to the phosphate-independent maleate-stimulated glutaminase preparation obtained from rat kidney by Katunuma and colleagues with respect to amino acid and carbohydrate content, apparent molecular weight, and relative transpeptidase and maleate-stimulated "glutaminase" activities. Both of these enzyme preparations are much more active in transpeptidation reactions with glutathione and related gamma-glutamyl compounds than with glutamine. In the absence of maleate, the enzyme catalyzes the utilization of glutamine (by conversion to gamma-glutamylglutamine, glutamate, and ammonia) at about 2% of the rate observed for catalysis of transpeptidation between glutathione and glycylglycine; the utilization of glutamine occurs about 8 times more rapidly in the presence of 0.1 M maleate. The transpeptidation and maleate-stimulated glutaminase reactions catalyzed by both enzyme preprations are inhibited by 5 mM L-serine in the presence of 5 mM sodium borate. Studies on gamma-glutamyl transpeptidase and maleate-stimulated glutaminase in the kidneys of fetal rats, newborn rats, and rats after weaning showed parallel development of these activities. The evidence reported here and earlier work in this laboratory strongly support the conclusion that maleate-stimulated glutaminase activity is a catalytic function of gamma-glutamyl transpeptidase. The studies on the ontogeny of gamma-glutamyl transpeptidase and other data are considered in relation to the proposal that this enzyme is involved in amino acid and peptide transport. Its possible role in renal formation of ammonia is also discussed.

Aging↗
PubMed1979

Cardiovascular responses to diazepam and midazolam maleate in the dog.

Previous clinical studies establishing the efficacy of midazolam maleate (RO 21-3981), a new water-soluble benzodiazepine for induction of anesthesia, have not critically evaluated the effects of this agent on the cardiovascular system. The present study compares the cardiovascular effects of midazolam maleate and diazepam in conscious dogs. Systemic arterial, pulmonary arterial and central venous pressures, cardiac output, LVmax dP/dt, heart rate and regional coronary blood flow were measured 3 min following intravenous administration of diazepam (0.5, 1.0, and 2.5 mg/kg) or midazolam maleate (0.25, 1.0, and 10.0 mg/kg). Midazolam maleate increased heart rate 10--20 per cent with all three doses and decreased mean arterial blood pressure approximately 10--20 per cent at 1.0 and 10 mg/kg. Cardiac output was increased 10--12 per cent with all three doses of midazolam maleate, and LVmax dP/dt was decreased 13--16 per cent at the two higher doses. Diazepam at all three doses did not alter heart rate or mean arterial blood pressure. Diazepam, 1.0 and 2.5 mg/kg, produced significant (17 per cent) decreases in LVmax dP/dt, and 2.5 mg/kg produced a significant (10 per cent) increase in cardiac output. Neither drug in any dosage altered regional coronary blood flow, systemic or coronary vascular resistance, stroke volume, or stroke work. Maximum alterations in cardiovascular variables occurred with doses of midazolam maleate that are 10--15 times the recommended clinical induction dosage. It is concluded that in concentrations necessary for induction of anesthesia midazolam maleate has minimal effects on cardiovascular function.

Animals↗
PubMed1976

Additive inhibition of renal bicarbonate reabsorption by maleate plus acetazolamide.

The effects of two potent inhibitors of renal bicarbonate reabsorption--maleate and acetazolamide--were investigated in the rat using clearance techniques. Acetazolamide given in high dose (50 mg/kg body wt) inhibited fractional bicarbonate reabsorption by ca. 30%, maleate (2.58 nmol/kg body wt) by 25%, and maleate plus acetazolamide by 54-72%. GFR was depressed, and urine volume was increased by both drugs in an additive manner. Maleate was equally effective as inhibitor of HCO3- reabsorption in the presence and absence of carbonic anhydrase activity. It is suggested that the site of action of both drugs is predominantly proximal, but they act on different steps in the transcellular HCO3- transport. A hypothetical mechanism of maleate action is presented, which takes into account the changes in passive HCO3- flux through the basolateral membrane.

Acetazolamide↗
PubMed1975

Timolol maleate, a new beta-adrenergic receptor blocking agent.

Some pharmacodynamic properties of an oxypropanolamine substituted novel heterocyclic compound are described. Initial studies involve comparison of the racemic mixture, dl-timolol maleate, with the beta-adrenergic receptor blocking agent propranolol in the rat, dog and cat. dl-Timolol maleate is shown to be a potent inhibitor of cardiovascular beta-adrenergic receptors activated by isoproterenol or adrenergic nerve stimulation. Blockade of alpha-adrenergic receptors is not observed even after extremely high doses. The compound is approximately 3 times more potent than propranolol in suppressing isoproterenol-induced cardioacceleration by the i.v. route of administration. dl-Timolol maleate is also extremely well absorbed when given orally, being then about 10 times more active than propranolol. Unlike propranolol, neither dl-timolol maleate nor its optical isomers possess demonstrable local anesthetic activity. Similar to propranolol and other beta-adrenergic receptor blocking agents, activity of the compound resides predominantly in the l-isomer (timolol maleate.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

Effects of maleate on CoA metabolism in rat kidney.

CoA transfer from acetoacetyl-CoA to maleate catalyzed by purified CoA transferase was studied. The thioester product of the reaction undergoes further chemical transformations and the final product appeared to be stable CoA derivative showing neither free SH group nor hydrolyzable thio-acyl bond. Similar product was obtained as the result of the reaction of addition of CoA to the double bond of maleic anhydride. This was confirmed by DEAE-chromatography. The decrease of free CoA and acid soluble acyl-CoA in kidney mitochondria respiring in the presence of maleate or in the kidney of maleate-treated rats occured without appreciable changes in acid insoluble acyl-CoA derivatives. As the result substantial loss of total content of CoA was found. The data indicate that maleate binds and removes CoA in the form of stable and metabolically inert compound.

Acetyl-CoA C-Acetyltransferase↗
PubMed1979

Corneal anesthesia after timolol maleate therapy.

Symptomatic superficial punctate keratitis associated with complete corneal anesthesia occurred in three patients after they had been taking timolol maleate for glaucoma. After discontinuation of the timolol maleate and substitution of conventional antiglaucomatous collyria, the keratitis gradually cleared with restoration of normal corneal sensitivity. Corneal sensitivity, measured in 25 additional patients taking timolol maleate, was markedly diminished in four patients, all of whom were elderly and had been using the drug for a minimum of three months. Timolol maleate does appear to have some local anesthetic properties in human cornea after chronic use by susceptible individuals.

Aged↗
PubMed1976

Direct dopaminergic action of lisuride hydrogen maleate, an ergot derivative, in mice.

Lisuride hydrogen maleate induced stereotyped behaviour in normal as well as in reserpinized mice. It antagonized the motor depression and hypothermia induced by reserpine. On i.p. administration the compound was about as effective as apomorphine and D-amphetamine. As with apomorphine and in contrast to D-amphetamine the effects of lisuride hydrogen maleate in reserpinized mice were not impaired by additional treatment with alpha-methyl-p-tyrosine methylester. In untreated mice, the substance was very potent in lowering body temperature with significant hypothermia measured after dosages as low as 0.10 mg/kg i.p. Occurrence of stereotyped behaviour and hypothermia could be prevented by the dopaminergic antagonist haloperidol. From these data it is concluded that lisuride hydrogen maleate in addition to its interaction with serotoninergic systems is a potent dopaminergic agonist with a probably direct action on dopaminergic receptors. Further arguments in support of such an action of lisuride hydrogen maleate are, in addition to biochemical data, its serum prolactin lowering effect in rats, its strong emetic action in dogs and its effects on rat behaviour.

Animals↗
PubMed1979

Treatment of variant angina pectoris with perhexilene maleate.

Three patients with variant angina pectoris resistant to therapy with nitrates and propranolol were treated with perhexilene maleate. Two patients had normal coronary arteries with documented coronary artery spasm, while the third patient had a fixed coronary artery obstruction. In all three patients, attacks of variant angina pectoris disappeared following institution of therapy with perhexilene maleate. When the dose of this drug was decreased to 100 mg per day or less, symptoms reappeared in all patients. Reinstitution of therapeutic doses of perhexilene maleate once again resulted in complete control of symptoms. Perhexilene maleate is therefore a useful agent for the treatment of variant angina pectoris.

Angina Pectoris↗
PubMed1979

Perhexiline maleate in the treatment of severe angina pectoris.

Perhexiline maleate was used as a prophylactic agent in 26 patients suffering from severe angina pectoris. The mean duration of treatment was 8.9 months, with a maximum of 28 months. Fifteen patients experienced a reduction in frequency of attacks to less than one-third of their previous level; six experienced a reduction to two-thirds of their previous level; no patient showed an increase in attack rates. During the period of study, there was one death. Frequently observed side effects included dizziness, gastrointestinal irritation and malaise. One patient developed clinically apparent hepatic dysfunction which resolved on withdrawal of perhexiline maleate, but recurred after rechallenge with a lower dose of the drug; the results of liver function tests in five others showed mild abnormalities. One patient developed peripheral neuropathy after taking perhexiline maleate for 18 months, but this resolved in two months after cessation of therapy. Good responses to perhexiline maleate were observed in patients who were concurrently treated with beta-adrenoreceptor blocking drugs.

Alprenolol↗
PubMed1979

Perhexiline maleate-induced cirrhosis.

The authors report the cases of 2 patients who died from cirrhosis after receiving perhexiline maleate, a drug widely used in Europe for the treatment of angina pectoris. Perhexiline maleate had been ingested for 24 and 28 mo, respectively. Manifestations of cirrhosis included jaundice, hepatic encephalopathy, ascites, and portal hypertension. Associated manifestations of intolerance to perhexiline maleate included peripheral neuropathy in 1 patient and marked weight loss in both. Histologic lesions resembled those observed in patients with alcoholic liver disease. Ultrastructural lesions included numerous enlarged lysosomes containing myeloid figures. Histochemical stains demonstrated increased phospholipid content of the hepatocytes. These findings are consistent with the view that prolonged administration of perhexiline maleate may induce both histologic lesions resembling those of alcoholic liver disease and ultrastructural and histochemical lesions resembling those of phospholipidosis.

Aged↗
PubMed1978

Perhexiline maleate in the treatment of angina pectoris. Five years of personal clinical experience.

A five-year personal experience of the use of perhexiline maleate (Pexid) in the treatment of severe angina pectoris is presented. Ninety-four patients, all severely incapacitated by cardiac pain, received perhexiline maleate for an average period of 12.2 months. Perhexiline maleate was used either alone or, more commonly, in conjuction with other antianginal therapy, such as beta-adrenergic receptor blocking agents. The results demonstrate that perhexiline maleate is a very effective agent which appears to be safe for long-term usage. Side effects have been frequent, and occasionally bothersome, but all have been transient and dose-dependent. The possibility that the regimens of treatment may materially improve long-term prognosis is raised.

Adrenergic beta-Antagonists↗
PubMed1978

Maleate induced change in the kidney binding of mercury in rats pretreated with cadmium.

The kidney uptake of Hg2+ was increased by Cd2+-pretreatment when Hg2+ was given intraperitoneally but not subcutaneously. Subsequent s.c. administration of maleate increased Hg2+ release from the kidneys only if Hg2+ was given subcutaneously. Neither the effect of Cd2+, nor that of maleate, on the distribution of Hg2+ among the renal soluble protein fractions was affected by the route of Hg2+ administration. The protective effect of Cd2+-pretreatment against the nephrotoxic effect of Hg2+ was also independent of the route of Hg2+ administration. Maleate given in nephrotoxic doses removed Hg2+ and copper, but not Cd2+ from the renal metallothionein fraction. Mercury in the urine, however, was not complexed by proteins with the molecular weight of thionein, but was bound to high molecular weight proteins and diffusible molecules. These findings are discussed in relation to the role of metallothionein in the interaction between Cd2+ and Hg2+.

Animals↗