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At least 307 records · Page 17Linked to original sources
PubMed2003

Evaluation of stability of enalapril maleate in solid phase.

The influence of temperature (from 383 to 348 K) and relative humidity (from 25.0 to 76.4%) on the stability of enalapril maleate in the solid phase was investigated. Changes in the concentration enalapril maleate were followed by a HPLC method with UV detection. The kinetic and thermodynamic parameters [E(a) (kJ mol(-1))=168.5+/-27 for RH=0% and 149.1+/-48 for RH=76.4%; deltaH(not equal ) (kJ mol(-1))=166.1+/-30 for RH=0% and 146.6+/-50 for RH=76.4%; deltaS(not equal) (J (K(-1) mol(-1)))=120.3+/-169 for RH=0% and 82.1+/-110 for RH=76.4%) of the decomposition reaction were calculated.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2004

Chemometric determination of amiloride hydrochloride, atenolol, hydrochlorothiazide and timolol maleate in synthetic mixtures and pharmaceutical formulations.

Different chemometric methods such as classical least squares (CLS), principal components regression (PCR) and partial least squares with one dependent variable (PLS-1) applied on UV spectral data (0 D) and on their first derivatives (1 D) were evaluated for the simultaneous quantification of samples containing mixtures of amiloride hydrochloride, atenolol, hydrochlorothiazide and timolol maleate. Their performances were compared by means of ANOVA tests, which evidenced that 0 D-PCR, 0D-PLS-1, 1D-PCR, 1D-PLS-1, were reproducible and gave statistically similar results, while 0 D-CLS and 1D-CLS displayed higher variances than the former and failed to comply with the Levene's variance homogeneity test at different stages of the method comparison and validation process. The four statistically equivalent procedures were successfully applied to the analysis of synthetic samples with two to four analytes and to commercial tablet preparations containing amiloride hydrochloride and hydrochlorothiazide alone or in association with atenolol or timolol maleate.

Amiloride↗
PubMed2003

Structural analyses and magnetic properties of 3D coordination polymeric networks of nickel(II) maleate and manganese(II) adipate with the flexible 1,2-bis(4-pyridyl)ethane ligand.

Two novel inorganic-organic hybrid 3D extended networks of Ni(II) and Mn(II) having molecular formulas [(maleate)(2)Ni(3)(bpe)(4)(H(2)O)(4)](NO(3))(2).H(2)O (1) and [(adipate)Mn(bpe)] (2) (bpe = 1, 2-bis(4-pyridyl)ethane), respectively, have been synthesized and characterized by single-crystal X-ray diffraction studies and low-temperature (300-2 K) magnetic measurements. Compound 1 crystallizes in the monoclinic system, space group C2/c (No. 15), with chemical formula C(56)H(62)N(10)Ni(3)O(19), a = 30.955(4) A, b = 12.705(3) A, c = 17.058(5) A, beta = 117.26(2) degrees, and Z = 4. Compound 2 crystallizes in the triclinic system, space group Ponemacr; (No. 2), with chemical formula C(18)H(20)MnN(2)O(4), a = 8.492(2) A, b = 9.444(2) A, c = 11.533(3) A, alpha = 97.19(1) degrees, beta = 94.64(1) degrees, gamma = 105.02(1) degrees, and Z = 2. The structure determination reveals for both a 3D network. Compound 1 contains two crystallographically independent Ni(II) ions in different octahedral environments. Ni(1) lies on an inversion center, and its coordination environment comprises two chelating maleate anions and two bpe nitrogen donors, while the Ni(2) ion is surrounded by meridionally disposed three bpe N atoms, two water molecules, and one oxygen donor from the dicarboxylate anion. Of the three crystallographic independent bpe ligand, one presents an anti and the others a gauche conformation. The corresponding N-to-N distances are 9.344, 6.543, and 6.187 A. Variable-temperature magnetic susceptibility measurement of the complex reveals the existence of a dominant ferromagnetic interaction within the molecule. Compound 2 is composed of Mn(2) dimer units linked by adipate anions to form corrugated 2D sheets which, on interconnection through bpe (anti conformation, N-to-N distance of 9.391 A), produces an interpenetrated 3D alpha-polonium-related type net. Complex 2 reveals to be antiferromagnetic fitting data using a dimeric Mn(II) model that considers negligible magnetic transmission through the carbon skeleton of adipate and the bpe pathway.

Journal Article↗
PubMed2003

Successful repair of aortic and mitral incompetence induced by methylsergide maleate: confirmation by intraoperative transesophageal echocardiography.

Methylsergide maleate, an effective anti-migraine medication, has a well-documented association with left-sided cardiac valve dysfunction. Prior reports have described cardiac valve dysfunction in patients using methylsergide chronically for a minimum of 6 years, with surgical intervention consisting of valve replacement for patients with intractable congestive heart failure. We report a 51-year-old woman who developed severe mitral and aortic valvular dysfunction after taking methylsergide maleate for migraine headaches for a period of 19 months, and who subsequently underwent aortic and mitral valve repair with excellent short-term results.

Aortic Valve↗
PubMed1999

Search for related substances in market products containing enalapril maleate as the active principle.

This study's main object was the determination of substances, by means of high-performance liquid chromatography (HPLC), that are related to enalapril maleate in medicinal tablets. The research was on products containing a 20 mg active principle with a 12-month delta t and on those batches near their expiration date with an enalapril maleate concentration of 10, 5, and 2.5 mg.

Antihypertensive Agents↗
PubMed2004

In vitro and ex vivo permeation studies of chlorpheniramine maleate gels prepared by carbomer derivatives.

The antihistaminic chlorpheniramine maleate (CPM) is used for symptomatic relief of hypersensitivity reactions and in pruritic skin disorders. At present, the drug is marketed in tablet, capsule, syrup, cream, and injectable dosage forms. Chlorpheniramine maleate has some side effects when taken orally. Due to its first pass effect, only 25%-45% of the orally administered dose reaches the blood circulation. To bypass these disadvantages, we aimed to investigate percutaneous absorption of CPM from gel formulations prepared with different carbomer derivatives (Carbopol 934, 940, 941, 2984, 980, and 981; main differences are related to presence of a comonomer and cross-link density). Cellulose membrane was used as the diffusion barrier for all the formulations' drug-release studies. The release of active substance from carbopol derivatives, which have the least cross-linking density (Carbopol 941 and 981) was found to be numerically higher than the others. The formulation (F8; 1% Carbopol 941) that exhibited the maximum drug release through the cellulose membrane was further studied for drug release by using polyurethane membrane, excised rat skin, and human skin. The penetration of the active substance through different diffusion barriers was found to be statistically different (p<0.05) when compared. Of all the different diffusion barriers, rat skin gave the closest results to human skin. Thus topical application of CPM in the carbomer gel may be of potential use for local activity. The type and concentration of carbomers can affect drug release. The synthetic membranes are useful in assessments of formulations in quality assurance but they do not give definite indication of how a formulation will behave when it is used on skin.

Acrylic Resins↗
PubMed1992

The inhibition of Na, K-ATPase, and Mg-ATPase by timolol maleate in cultured non-pigmented epithelial cells of the ciliary body.

Bovine, non-pigmented, ciliary body epithelial cells were isolated and grown in culture to determine whether timolol maleate might affect the activity of their plasma membrane ATPases. The possible effects were tested in drug concentrations in a range of 5 x 10(-19) to 5 x 10(-5) M over an incubation period of 30 min at 37 degrees. Assays of specific activity showed that the drug significantly (p less than .001 for most concentrations) inhibited both Na,K-ATPase and Mg-ATPase. However, the inhibition was partially reversed in concentrations greater than 10(-6) M for Na,K-ATPase and 10(-5) M for Mg-ATPase. The latter enzyme also indicated a second partial reversal in activity at concentrations between 10(-12) and 10(-9) M. These reversals in activity suggest that more than one binding site is involved in the inhibition of both enzymes. Since Na,K-ATPase in non-pigmented, ciliary body cells is responsible for the generation of aqueous fluid and the intraocular pressure (IOP), this inhibition demonstrates a possible mechanism for the pharmacological action of timolol maleate in lowering IOP.

Amino Acid Sequence↗
PubMed1997

The effect of 0.5% timolol maleate on the ocular perfusion of ocular hypertensive patients by scanning laser flowmetry.

To understand the effect of 0.5% timolol maleate on the ocular perfusion of the optic disc and macula in ocular hypertensive patients, we enrolled 10 males and 15 females without any systemic or ocular disease, except intraocular pressure higher than 20 mmHg. Their average age was 33 +/- 13 y/o (range 14-45). Under the randomized, double-masked design, one drop of 0.5% timolol maleate was given in one eye, and placebo in the fellow eye. Heart rate, blood pressure, intraocular pressure, and ocular perfusion were measured at baseline, and then 30 minutes and 2 hours after treatment. Ocular perfusion was measured by Heidelberg Retina Flowmeter (Heidelberg Engineering GmbH, Heidelberg, Germany). We used 10 degrees measurement field and 10 x 10 pixels measurement frame. Four areas were measured, i.e., temporal upper, temporal lower, and nasal parts of the optic disc, and macula. In comparison to the baseline, the treated eyes had a slight reduction of blood flow, volume, and velocity 30 minutes after treatment, but these parameters came back close to the baseline value at 2 hours after treatment. Similar changes were also noted in the control eyes. The results showed that a single drop of 0.5% timolol had minimal effects on the retinal and macular circulation within 2 hours after treatment.

Adolescent↗
PubMed2005

Continuous monitoring of circadian variations in intraocular pressure by telemetry system throughout a 12-week treatment with timolol maleate in rabbits.

AIM: The aim of this study was to examine the effect of a 12-week treatment with two formulations of timolol maleate on the amplitude of the circadian fluctuation in intraocular pressure (IOP). METHODS: Conscious Japanese White rabbits housed under a controlled 12-hour light-dark cycle were used. IOP was measured by a telemetry system. Each animal was treated topically for 12 weeks with 0.5% timolol solution (TM) twice-daily, 0.5% timolol gel-forming solution (TM-gel) once-daily, or saline twice-daily, and the circadian variation in IOP was measured every week. RESULTS: Administration of TM or TM-gel did not change IOP in the light phase, but significantly reduced it in the dark phase in each of the 12 weeks. The IOP reductions at 2 h after administration in the TM and TM-gel groups over the 12 weeks were, respectively, 3.6 +/- 0.3 mmHg and 3.4 +/- 0.2 mmHg versus the Saline group. The amplitudes of the circadian fluctuations in IOP in the TM group in weeks 3, 6, and 12 were 15%, 15%, and 18% smaller than those in the Saline group, while the corresponding values for the TM-gel group were 18%, 16%, and 19%, respectively. CONCLUSIONS: TM-gel administered once-daily was as effective at lowering IOP as TM administrated twice-daily over the 12-week experimental period. This study reveals that, in rabbits, both formulations of the timolol maleate induced significant IOP reductions in the dark phase and decreased the amplitudes of the circadian fluctuations in IOP for 12 successive weeks.

Adrenergic beta-Antagonists↗
PubMed1998

Stability of enalapril maleate in three extemporaneously prepared oral liquids.

The stability of enalapril 1 mg/mL (as the maleate) in deionized water, citrate buffer solution, and a sweetened suspending agent at two temperatures was studied. Twenty enalapril 10-mg tablets were crushed to a powder. Deionized water, citrate buffer solution, or sweetened vehicle was added to produce three 200-mL batches of each liquid; the expected final concentration of enalapril in each was 1 mg/mL. Each formulation was stored in 10 60-mL bottles, 5 of which were stored at 4 degrees C and 5 at 25 degrees C. Samples were collected on days 0, 7, 14, 28, 42, 56, 70, and 91 for visual inspection and analysis by high-performance liquid chromatography; pH was measured at each sampling time as well. The mean concentration of enalapril in the three liquids at 4 degrees C was > 94% of the initial concentration throughout the 91-day study period. At 25 degrees C, the mean concentration of enalapril was > 90% for 56 days and > 92% for 91 days in both citrate buffer solution and sweetened vehicle. The pH of the liquid prepared with deionized water and stored at 25 degrees C decreased by 2.0 pH units. Enalapril 1 mg/mL (as the maleate) in three extemporaneously compounded oral liquids was stable for 91 days at 4 and 25 degrees C with the exception of enalapril in deionized water, which was stable for only 56 days at 25 degrees C.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1998

Effect of continued treatment with timolol maleate on corneal endothelium: a fluorophotometric study.

PURPOSE: To verify whether the long-term use of timolol maleate is toxic for the corneal endothelium and whether the treatment time is a predisposing factor. METHODS: We used fluorophotometry to study 40 eyes that had been treated with timolol maleate uninterruptedly during a prolonged time (from 6 months to 14 years). The results obtained were compared with a sample of 40 hypertensive eyes that had not received any treatment. RESULTS: No statistically significant differences were found between the coefficient values of endothelial permeability between the treated and nontreated subjects. In addition, no differences were found in the coefficient of endothelial permeability between subjects treated with timolol in different treatment periods (between 6 and 12 months, between 1 and 5 years, and for > 5 years). CONCLUSION: These results suggest that long-term treatment with timolol has little effect on the integrity of the corneal endothelium.

Aged↗
PubMed1979

Effect of the antihistamines, brompheniramine maleate and triprolidine hydrochloride, on performance in man.

1 Effects of brompheniramine maleate (4 and 12 mg) and triprolidine hydrochloride (2.5 and 10 mg) on visuo-motor coordination, and on subjective assessments of performance, well-being and sleep were each studied in six subjects at 0.5, 1.5, 3.0, 5.0 and 7.0 h after ingestion. The doses refer to immediate and sustained release preparations respectively. 2. Triprolidine hydrochloride (2.5 mg) had an immediate effect on performance which persisted to 3.0 h, and the sustained release preparation (10 mg) impaired performance from 1.5 to 5.0 h. Brompheniramine maleate (4 mg) impaired performance from 1.5 to 3.0 h, and the sustained release preparation (12 mg) impaired performance at 1.5 h. There were no consistent changes in the subjective assessments of performance, or of well-being and sleep. 3. The studies emphasize the variable effects of antihistamines on performance, and suggest that effects on performance of sustained release preparations may be similar to those of the usual form. Sustained release preparations may provide an advantage in clinical practice if the antihistaminic activity is prolonged.

Adult↗
PubMed1980

Azatadine maleate in perennial allergic rhinitis: effects on clinical symptoms and choice reaction time.

1 The efficacy of the antihistamine azatadine maleate at maximum recommended dosage (4 mg/day) for 1 week was assessed relative to placebo in a double-blind crossover study of twenty patients with perennial allergic rhinitis. 2 Sixteen patients reported significant improvement in their clinical symptoms while taking the active drug. 3 The size of skin test weals for both histamine provocation and common inhalant allergens (prick test) diminished significantly after the azatadine treatment. There was no correlation between inhibition of skin reactions and symptom improvement. 4 Eight subjects reported sedative effects attributable to azatadine maleate. Their performance on a choice reaction to placebo occurred in the non-sedated group.

Adolescent↗
PubMed1993

Clinical trials with velnacrine: (PROPP) the physician reference of predicted probabilities--a statistical model for the estimation of hepatotoxicity risk with velnacrine maleate.

Safety observations during the clinical development of Mentane (velnacrine maleate) have included the occurrence of generally asymptomatic liver enzyme elevations confined to patients with Alzheimer's disease (AD). The clinical presentation of this reversible hepatocellular injury is analogous to that reported for tetrahydroaminoacridine (THA). Direct liver injury, possibly associated with the production of a toxic metabolite, would be consistent with reports of aberrant xenobiotic metabolism in Alzheimer's disease patients. Since a patient related aberration in drug metabolism was suspected, a biostatistical strategy was developed with the objective of predicting hepatotoxicity in individual patients prior to exposure to velnacrine maleate. The method used logistic regression techniques with variable selection restricted to those items which could be routinely and inexpensively accessed at screen evaluation for potential candidates for treatment. The model was to be predictive (a marker for eventual hepatotoxicity) rather than a causative model, and techniques employed "goodness of fit", percentage correct, and positive and negative predictive values. On the basis of demographic and baseline laboratory data from 942 patients, the PROPP statistic was developed (the Physician Reference Of Predicted Probabilities). Main effect variables included age, gender, and nine hematological and serum chemistry variables. The sensitivity of the current model is approximately 49%, specificity approximately 88%. Using prior probability estimates, however, in which the patient's likelihood of liver toxicity is presumed to be at least 30%, the positive predictive value ranged between 64-77%. Although the clinical utility of this statistic will require refinements and additional prospective confirmation, its potential existence speaks to the possibility of markers for idiosyncratic drug metabolism in patients with Alzheimer's disease.

Age Factors↗
PubMed1991

Evaluation of HP 029 (velnacrine maleate) in Alzheimer's disease.

HP 029 (1,2,3,4-tetrahydro-9-aminoacridin-1-ol-maleate) is a cholinesterase inhibitor and one of a series of compounds synthesized at Hoechst-Roussel Pharmaceuticals Inc. (HRPI) as a potential therapeutic agent for senile dementia of the Alzheimer type (SDAT). An ongoing clinical development program for HP 029 (velnacrine maleate) reflects a rational, traditional progression from therapeutic concept through clinical evaluation. Prior to the initiation of outpatient studies, sufficient data had been obtained from normal volunteers and hospitalized patients to support the following conclusions: the pharmacokinetic profile of HP 029 in young and elderly normal men is predictable; tolerance and safety data for HP 029 using normal volunteers poorly correlates with experience in patients with SDAT; patients with SDAT exhibit marked intersubject variability in tolerance within a suspected therapeutic dose range; mandatory endpoints for drug discontinuation for outpatients can be reliably established in an inpatient environment. Subsequently, Protocol 201 was initiated as a multicenter, multistage investigation of HP 029 in patients with probable SDAT (NINCDS-ADRDA criteria). A dose-ranging component determined patient eligibility for a subsequent dose-replication phase based upon explicit safety and efficacy criteria defined within protocol. One a priori specified interim analysis was conducted by the sponsor (HRPI) for administrative purposes after completing approximately 50% of the planned sample (September 1989). Results suggested that (1) beneficial effects of HP 029 existed on key and secondary measures for the approximately 30% of enrolled patients; (2) interim results would provide an accurate reflection of the results at the conclusion of the study (1991); (3) HP 029-induced hepatocellular injury appeared to be a reversible, predominantly dose-related event; and (4) cholinergically mediated adverse events are infrequent and clinically inconsequential at dosages less than or equal to 225 mg/day. Post hoc hypotheses based on the interim dataset suggest that: (1) carry-over effects of HP 029 exist within a dose-ranging/dose-replication paradigm that militate against the utility of an "enriched population" design; (2) beneficial effects are more robust on initial exposure to HP 029 with effects discerned on both memory and arousal; (3) patient characteristics associated with toxicity or response are not identified; (4) dosage reduction in subsequent efficacy trials may reduce hepatocellular injury and yield clinically unimportant differences in overall efficacy results.

Aged↗
PubMed1982

Hypotension in the horse induced by acepromazine maleate.

The hypotensive effect of acepromazine maleate was related to both the dose and route of administration. The degree and duration of hypotension varied between individual horses. In general, intravenous administration produced a more rapid maximum effect than intramuscular injection and the larger the dose the longer blood pressure remained at low levels. Average systolic pressure (of 6 horses) remained significantly below control values for more than 6 h after an intramuscular injection of 0.05 mg acepromazine maleate/kg body weight. Respiratory rate was markedly decreased, with the duration, but not the degree of bradypnoea related to the dose administered. A slight, transient decrease in body temperature was observed. Heart rate was not significantly influenced by administration of acepromazine maleate.

Acepromazine↗
PubMed1978

The effect of 1.5% timolol maleate on intraocular pressure.

A controlled trial was instituted to compare the effect on intraocular pressure of topical administration of timolol maleate with epinephrine hydrochloride. A bottling error by the manufacturer resulted in the placebo bottles containing 1.5% timolol maleate. This drug given twice a day for two weeks significantly reduced intraocular pressure and produced no side effects.

Administration, Topical↗