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PubMedDate not supplied

Effects of timolol and dorzolamide on retrobulbar hemodynamics in patients with newly diagnosed primary open-angle glaucoma.

The authors considered a group of patients with newly diagnosed primary open-angle glaucoma studying the effects of a 4-week treatment with timolol or dorzolamide on retrobulbar vessels. Ocular hemodynamics were assessed by means of color Doppler imaging of the ophthalmic artery, the temporal short posterior ciliary arteries (SPCAs) and the central retinal artery. For each vessel, systolic and diastolic blood flow velocities were measured, and the resistivity index (RI) was calculated. The only significant result was a reduction of temporal SPCA RI after dorzolamide treatment in comparison with baseline (p = 0.011). In the same group, dorzolamide treatment had a slight and nonsignificant increase in temporal SPCA diastolic velocity. The resistance decrease observed after dorzolamide treatment in the ciliary circulation may be due to the decrease in intraocular pressure or a possible direct vasodilating effect of the drug.

Adrenergic beta-Antagonists↗
PubMed1980

Long-term treatment with timolol ophthalmic solution in open-angle glaucoma.

A preselected population of 96 patients (67 glaucomas, 29 ocular hypertensions) were followed for an average period of 30 months. Timolol eye drops were administered either alone, in dosage strengths of 0.25 or 0.5% or in combination with other antiglaucoma drugs. 9 patients were lost to follow-up after a mean treatment duration of 15.3 months; glaucoma had been stabilized in all of them. 10 patients had unsatisfactory intraocular pressure control and 7 had to undergo trabeculectomy (9 of these 10 patients had campimetric glaucoma at the beginning of the study), whereas 76 patients had satisfactory intraocular pressure control and, in the majority, stabilization of glaucoma had been obtained. In 77% of this preselected population glaucoma was stabilized over a period of 3 years (i.e. close to two thirds of those starting treatment, 70% of which had campimetric glaucoma).

Glaucoma↗
PubMed1987

Management of retinal detachment without tear by topical therapy (atropine and timolol).

14 various kinds of retinal detachments were treated by timolol + atropine eye drops. 4 cases were primary procedures and required no further surgery. 10 cases were recurrent detachments after episcleral or endo-vitreous surgery. In 8 cases there was a notable proliferative vitro-retinopathy. 10 cases were completely flattened by this medication and we obtained the reapplication of the posterior pole and the upper retina in the 4 other cases.

Administration, Topical↗
PubMed1978

Concomitant administration of timolol and hydrochlorothiazide/amiloride in hypertensive patients. Results of a titration study.

In an open dose titration study we evaluated the antihypertensive effect of the concomitant administration of timolol and hydrochlorothiazide/amiloride, administered on a b.i.d. basis. Twenty-eight out of 39 patients completed the study. Supine and standing systolic and diastolic blood pressures and pulse rate were significantly lower at the end of the titration period than at the end of the diuretic period.

Adult↗
PubMed2004

Vitamin B2-sensitised photooxidation of the ophthalmic drugs Timolol and Pindolol: kinetics and mechanism.

The kinetics and mechanistic aspects of the riboflavin-photosensitised oxidation of the topically administrable ophthalmic drugs Timolol (Tim) and Pindolol (Pin) were investigated in water-MeOH (9:1, v/v) solution employing light of wavelength > 400 nm. riboflavin, belonging to the vitamin B(2) complex, is a known human endogenous photosensitiser. The irradiation of riboflavin in the presence of ophthalmic drugs triggers a complex picture of competitive reactions which produces the photodegradation of both the drugs and the pigment itself. The mechanism was elucidated employing stationary photolysis, polarographic detection of dissolved oxygen, stationary and time-resolved fluorescence spectroscopy, and laser flash photolysis. Ophthalmic drugs quench riboflavin-excited singlet and triplet states. From the quenching of excited triplet riboflavin, the semireduced form of the pigment is generated, through an electron transfer process from the drug, with the subsequent production of superoxide anion radical (O(2)(*-)) by reaction with dissolved molecular oxygen. Through the interaction of dissolved oxygen with excited triplet riboflavin, the species singlet oxygen (O(2)((1)Delta(g))) is also generated to a lesser extent. Both O(2)(*-) and O(2)((1)Delta(g)) induce photodegradation of ophthalmic drugs, Tim being approximately 3-fold more easily photooxidisable than Pin, as estimated by oxygen consumption experiments.

Adrenergic beta-Antagonists↗
PubMed1984

Efficacy and tolerance of a fixed ratio combination of hydrochlorothiazide, amiloride and timolol, taken before or after food, in the treatment of hypertension.

An open study was carried out in general practice to assess the efficacy and tolerance of a fixed ratio combination of hydrochlorothiazide (25 mg), amiloride (2.5 mg) and timolol (10 mg) in the treatment of patients with mild to moderate hypertension, and to determine if there were any differences in response when medication was taken before or after food. A total of 663 patients was studied and received 1 to 2 tablets once daily for a period of 12 weeks; 322 patients took their medication before and 341 after food. The results showed that there were similar significant reductions in systolic and diastolic blood pressure and in heart rate in both groups, over half of the patients being controlled (less than 90 mmHg diastolic) after 2 weeks and 80% by the end of the study period. Relatively few adverse effects were reported and the incidence during treatment was less than that recorded on entry to the study. There was no evidence to suggest that the timing of drug intake in relation to food had any effect on the efficacy or tolerance of the combination.

Adult↗
PubMed2006

The effects of a timolol maleate gel-forming solution on normotensive beagle dogs.

The effects of a timolol maleate gel-forming solution (TMGS) on intraocular pressure (IOP), blood pressure (BP), and pupil size (PS) were evaluated in normotensive dogs. TMGS was administered once daily to six normotensive beagle dogs. TMGS administration reduced IOP and PS. The hypotensive effect persisted for 24 hr after the administration. The mean reduction in IOP was 5.3 mm Hg (P<0.01). The changes in BP and PS were not significant. These results suggest that TMGS can potentially be used in the treatments of glaucoma and ocular hypertension in dogs.

Animals↗
PubMed2004

In vitro evaluation of a hydroxypropyl cellulose gel system for transdermal delivery of timolol.

In this work, the development of a gel reservoir for a timolol (TM) transdermal iontophoretic delivery system is investigated. TM gel is prepared using hydroxypropyl cellulose (HPC) and the permeability of TM from the gel through an artificial membrane (Polyflux) and pig stratum corneum (SC) is studied. For a constant TM donor concentration, the TM transport across the Polyflux membrane alone decreases when the concentration of the gel increases due to increase of the gel viscosity. For constant gel concentration, however, the TM permeation across the membrane increases when the TM donor concentration increases. In addition, no effect of the electrical current (iontophoresis, current density 0.5 mA cm-2) on the TM permeation is found. For the combination of the Polyflux membrane with pig SC, the TM transport is much lower than for the membrane alone and the SC fully controls the TM delivery. In this case, the application of electrical current enhances the TM delivery 13-15 times in comparison to passive (no current) transport. According to our estimation, the daily TM dose (10-60 mg) can be delivered by an iontophoretic patch with Polyflux membrane area of 6-36 cm2 containing 20% (w/w) HPC gel and 15 mg cm-3 of TM.

Adrenergic beta-Antagonists↗
PubMed1986

Debrisoquine polymorphism and the metabolism and action of metoprolol, timolol, propranolol and atenolol.

The contribution of debrisoquine polymorphism to the metabolism and action of beta-adrenoceptor antagonists (beta-blockers) varies widely between drugs. Oxidation phenotype is a major determinant of the metabolism, pharmacokinetics and some of the pharmacological actions of metoprolol, bufuralol and timolol. The poor metabolizer phenotype is associated with an increased area under the plasma drug concentration vs. time curve, a prolongation of elimination half-life and a more intense and sustained beta-blockade. The stereoselective metabolism of metoprolol also displays phenotypic differences, which should be taken into account when interpreting plasma concentration vs. response relationships. Studies in vivo and in vitro have identified some of the metabolic pathways which are subject to this defect, namely the alpha-hydroxylation and the O-demethylation of metoprolol and the 1'-hydroxylation of bufuralol. In contrast, the pharmacokinetics and pharmacodynamics of propranolol, which is also extensively oxidized, are not related to debrisoquine polymorphism, although 4'-hydroxypropranolol formation is deficient in the poor metabolizer phenotype. The disposition of atenolol, which is almost completely eliminated unchanged by renal and faecal excretion, is independent of oxidation phenotype. If standard doses of some beta-blockers are used in poor metabolizers, these patients may be susceptible to concentration-related adverse reactions and they may also require lower and less frequent dosing for control of angina pectoris.

Adrenergic beta-Antagonists↗
PubMed2001

[A comparative study of the ocular tolerance of 3 timolol-based preparations: the influence of preservatives on ocular tolerance].

PURPOSE: Ophthalmic preparations can cause toxic ocular reactions, often associated with the use of preservatives. The aim of this study was to compare the ocular tolerance of three ophthalmic preparations based on timolol: a preservative free ophthalmic preparation (Timabak) and two other commercially available preserved preparations (Timoptol) and Timoptol LP). METHODS: The effect of repeatedly instilling eye drops for 28 days on rabbit eyes was assessed in vivo by mean of a confocal laser scanning ophthalmoscope. The corneal microlesions were selectively marked by fluorescein. RESULTS AND CONCLUSION: The overall results show the good ocular tolerance of the three tested products. However, a closer comparison between the products brought out differences in the extent of lesions among the tested products depending on their composition. Indeed the preservative free eye drops appeared better tolerated than the two preserved preparations.

Adrenergic beta-Antagonists↗
PubMed2002

[Physiologic significance of the interaction between timolol and free amino acids in eye structures].

The authors analyze the interaction of timolol maleate (Timoptol, Léciva Prague) with free amino acids with regard to the effect on intraocular pressure. The different colour reaction of an amino acid mixture with Timoptol, the decline of radioactivity of Na[I125] tyrosine with Timoptol and the formation of 8 radioactive fractions after addition of Timoptol to Na[I125] indicate: a) the specificity of interaction of each amino acid with Timoptol; b) suggest that between Timoptol and free amino acids a firm covalent bond develops with the concurrent development of a new biologically active metabolite. Evidence of the presence of a new metabolite is important from the aspect of understanding and more accurate definition of the action of Timoptol in tissue structures of the eye and thus also for possible effective treatment of glaucoma.

Adrenergic beta-Antagonists↗
PubMed2003

Enhancer effects on in vitro corneal permeation of timolol and acyclovir.

The aim of this study was to evaluate the ability of two non-toxic skin penetration enhancers, N-methylpyrrolidone (NMP) and a positively charged phospholipid mixture (PS), to increase in vitro corneal permeation of timolol maleate (TM) and acyclovir (AC) in comparison with two corneal absorption promoters, polyethylene glycol octadecyl ether (Brij 78) and sodium taurocholate (TA). In vitro experiments were performed on corneas from albino rabbits which were mounted in a perfusion apparatus. The concentrations of the enhancers being tested were: Brij 78 1%, PS 1%, TA 1%, NMP 5%, NMP 10%. The safety of the enhancers being tested was assessed in vitro by determining their effects on corneal hydration and in vivo by means of a modified Draize test. Calculating the amount of drug permeated at different time points (90 and 180 min) we observed that TA, PS and NMP 5% significantly increased the cumulative amount of AC permeated after 90 min but only PS was effective after 180 min. TA, Brij 78 and PS were able to increase significantly the amount of TM permeated after 90 min but after 180 min only Brij 78 retained its effect. TA, Brij 78 and NMP 10% significantly increased the percent hydration levels (% HL) compared to the control while PS and NMP 5% did not affect % HL. The results of in vivo ocular tolerability studies showed that the enhancers which caused an in vitro increase of % HL produced in vivo conjunctival and/or corneal damages. The results of this study suggest that PS could be regarded as a potential corneal enhancer to increase the intraocular bioavailability of AC and TM.

Acyclovir↗
PubMedDate not supplied

Hypotony and choroidal effusion induced by topical timolol and dorzolamide in patients with previous glaucoma drainage device implantation.

Three patients with glaucoma drainage devices and one patient who had trabeculectomy with mitomycin C were treated with a combination of topical timolol 0.5% and dorzolamide hydrochloride in the late postoperative period to decrease the intraocular pressure to the target level. All four patients developed ciliochoroidal effusions with hypotony that resolved with the discontinuation of the topical medication. Aqueous suppressants can induce ciliochoroidal effusions and hypotony in the late postoperative phase in some patients with glaucoma drainage devices. Discontinuation of the medication usually results in the resolution of the choroidal effusions.

Administration, Topical↗
PubMed2004

[Long-term efficacy and safety of combined topical antiglaucoma therapy--timolol & unoprostone vs. betaxolol & unoprostone].

PURPOSE: To evaluate long-term efficacy and safety of treatment combining topical beta-blockers and isopropyl unoprostone in primary open-angle glaucoma and normal-tension glaucoma patients. METHODS: A prospective, open-label, parallel-group clinical comparison trial was performed to evaluate efficacy and safety of treatment combining 0.5% betaxolol and 0.12% isopropyl unoprostone (B&U) or 0.5% timolol and 0.12% isopropyl unoprostone (T&U). Forty eyes of 40 patients, which were matched in the aging and the stage of glaucomatous visual field defect, were studied. Twenty patients were treated with B&U and the other twenty patients with T&U twice daily for 24 months. Goldmann intraocular pressure(IOP), Humphrey automated perimetry, blood pressure, heart rate, and peak flow were done every six months in each group. RESULTS: In the B&U treatment group, mean IOP was 21.2 mmHg at baseline and 18.3 mmHg(p < 0.005) after 2 years, and in the T&U treatment group it was 21.1 mmHg at baseline and 17.9 mmHg (p < 0.001) after 2 years. The cases in which MD value decreased over 2 dB were one in the B&U treatment group and three in the T&U treatment group. The average MD value was significantly improved from -7.40 dB to -5.90 dB after 2 years with B&U treatment(p < 0.05), but there was no difference with the T&U treatment. None of the patients stopped combined therapy because of side effects, though heart rate was significantly reduced only in T&U treatment group. CONCLUSION: Both combined treatments were effective for IOP reduction in glaucoma patients, and the data from the B&U treatment group suggested that B&U was more effective in maintaining visual field than T&U.

Adult↗
PubMed2004

[Comparison of the effects of latanoprost and timolol gel-forming solution on diurnal variation of intraocular pressure in normal-tension glaucoma].

OBJECTIVE: To compare the effects of latanoprost (Lat) and timolol gel-forming solution (Tg) on the diurnal variation of intraocular pressure (IOP) in normal-tension glaucoma (NTG). SUBJECTS AND METHODS: A total of 47 NTG patients (47 eyes) were randomly assigned to receive Lat alone (25 eyes) or Tg alone (22 eyes). IOP was measured at fixed time points during 24 hours before and after treatment with each drug. In addition, blood pressure and pulse rate were measured before and after treatment. RESULTS: Lat reduced IOP significantly at all time points of measurement. Tg reduced IOP significantly at all time points of measurement except at 22:00 and 03:00. Percent reductions in the IOP at 03:00 and in the mean diurnal IOP were significantly greater in the Lat group than in the Tg group. In the Lat group there was no change in diastolic pressure or pulse rate after treatment, but in the Tg group these parameters decreased significantly. CONCLUSIONS: Comparison of diurnal variation of IOP before and after treatment shows that Lat is more effective than Tg in lowering IOP. In addition, Lat does not affect blood pressure or pulse rate.

Adrenergic beta-Antagonists↗
PubMed2004

Nonequivalence behavior studies for the direct determination of enantiomeric purity and absolute configuration of timolol by NMR.

Direct determination of both the enantiomeric purity and absolute configuration of timolol was accomplished utilizing 1H NMR (400 MHz) spectroscopy with fast diamagnetic chiral solvating agent to dissimilarly perturb the spectra of enantiomeric solutes. Nonequivalence behavior was studied for all variables that affect populations and intrinsic spectra of the diastereomeric solvates. Optimization of the experimental conditions in terms of probe temperature, substrate concentration and solvating agent to substrate molar equivalents provided resolved enantiomeric signals suitable not only for chiral recognition but also for quantification. Enantiomeric impurity was determined on the basis of relative intensities of the tert-butyl methyl protons resonances; the assignment of enantiomeric configuration was based on the relative field positions of these resonances. The analysis of synthetic mixtures of the enantiomers by the proposed NMR method resulted in assay values which agreed closely with the known quantities of each enantiomer in mixtures tested. The mean +/-SD recovery values for the (R)-(+)-enantiomer was 100.0+/-1.6% of added antipode (n = 8). The optically pure enantiomers were used to establish the minimum detection limits of0.1%. The developed methodology represents a rapid and powerful tool for regulatory analysis.

Adrenergic beta-Antagonists↗
PubMed1992

Timolol in lipospheres.

Lipospheres carrying timolol (1) were obtained from microemulsions. They had lecithin, palmitic and decanoic acids as the main constituents. The sizes were between 300 and 400 nm and the amount of 1 incorporated varied from 2.7 to 4.8% according to the microemulsion used. Compound 1 was present in the lipospheres mainly as ion pairs in order to increase its lipophilicity. The difference found in the incorporation was principally due to the different lipophilicity of the ion pairs of 1.

Chemistry, Pharmaceutical↗