PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Timolol”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,045 records · Page 58Linked to original sources
PubMed1997

Tensioactivity and supramolecular organization of the palmitoyl prodrug of timolol.

PURPOSE: To improve the bioavailability of the ocular drug timolol by facilitating its transport through the cornea, an amphiphilic prodrug was synthesized via the addition of a palmitic chain by esterification. The present study was undertaken to investigate the physicochemical and tensioactive properties of the prodrug. METHODS: The amphiphilic properties of the prodrug were firstly investigated by the Wilhelmy plate method. The textures generated by the supramolecular organizations of the ester were visualized by optical microscopy. RESULTS: The prodrug clearly decreased the surface tension. Optical microscopy provided excellent evidence for the existence of lyotropic liquid crystalline phases: two isotropic but organized phases and a birefringent lamellar phase. CONCLUSIONS: The results from the ensemble of studies undertaken to determine the amphiphilic properties of the prodrug were all in accord with its ability to form liquid crystalline phases. The liquid crystalline state of the prodrug is believed to introduce a delay in the drug pharmacological effect.

Adrenergic beta-Antagonists↗
PubMed1991

Role of enzymatic lability in the corneal and conjunctival penetration of timolol ester prodrugs in the pigmented rabbit.

The main objective of this study was to investigate how enzymatic lability would affect the extent of corneal and conjunctival penetration of a series of alkyl, cycloalkyl, and aryl ester prodrugs of timolol in the pigmented rabbit. Enzymatic lability of the prodrugs was studied in corneal epithelial and conjunctival homogenates, while their corneal and conjunctival penetration was determined using the isolated tissues in the modified Ussing chamber. The straight-chain alkyl and the unsubstituted cycloalkyl esters were hydrolyzed more rapidly than their corresponding branched-chain and substituted analogues as well as the aryl esters. The corneal and conjunctival penetration of all prodrugs, regardless of enzymatic lability, varied parabolically with lipophilicity. Moreover, the enzymatically more labile straight-chain alkyl esters penetrated the cornea and the conjunctiva more readily than the more stable branched-chain esters of comparable lipophilicity. Enzymatic lability is, therefore, an additional factor that should be considered in designing alkyl ester prodrugs with improved ocular drug delivery characteristics. Enzymatic lability does not, however, play as important a role as lipophilicity in the corneal and conjunctival penetration of cycloalkyl and aryl ester prodrugs.

Animals↗
PubMed1988

A comparative evaluation of timolol maleate and pilocarpine in the treatment of chronic open angle glaucoma.

Ninety-two eyes with newly-diagnosed chronic open angle glaucoma (COAG) were treated in a randomised prospective trial with either timolol or pilocarpine. Their visual field survival was monitored on a 3-monthly basis over 2 years using both Goldmann and Friedmann perimetry. Concomitant tonometric data was derived by applanation. Fields were assessed and quantified using algorithms designed to give the greatest sensitivity for glaucomatous field loss. Microcomputer programmes specifically designed for this purpose were used in the data collection and subsequent analysis.

Aged↗
PubMed1990

The progress of the visual field in chronic simple glaucoma and ocular hypertension treated topically with pilocarpine or with timolol.

It is theoretically possible that the vascular effects of topical sympathetic beta-blocking therapy in chronic simple glaucoma (CSG) might tend to neutralise the beneficial effect of a reduced intraocular pressure on the preservation of the visual field. We therefore followed the progress of 422 right eyes and 420 left eyes of 483 patients with CSG and 119 right eyes and 132 left eyes of 151 patients with an original diagnosis of ocular hypertension (OH). These patients were observed for a minimum of one year and up to 13 years, being followed for an average of 5.1 years in the case of CSG and of 4.5 years in OH. The majority of eyes with CSG were treated topically with a miotic and 38% of these received beta blocking therapy in the form of topical timolol. It was concluded that despite suggestions that beta blockers might reduce vascular perfusion of the optic nerve head, which might in turn cause an adverse effect on the visual field progress, the results of this analysis showed that there was less mean deterioration of visual field in eyes treated with beta blocker plus miotic treatment compared with those on miotic therapy alone.

Administration, Topical↗
PubMed1993

Improved lung function tests on changing from topical timolol: non-selective beta-blockade impairs lung function tests in elderly patients.

Fifty-two elderly glaucomatous patients, without a history of asthma or obstructive airways disease, who were using topical timolol for control of intraocular pressure were recruited. Their topical therapy was changed to either betaxolol or pilocarpine. The change was associated with improvement in mean peak flow from 278 l/min to 328 l/min (t = 5.73, p < 0.001), mean FEV1 from 1.66 l to 1.85 l (t = 7.09, p < 0.001) and mean FVC from 2.40 l to 2.64 l (t = 5.07, p < 0.001). Change to either betaxolol or pilocarpine was associated with improved lung function tests. Lung function tests in a control group of 20 showed no significant changes. Both drugs maintained control of intraocular pressure but betaxolol had fewer ocular side effects.

Administration, Topical↗
PubMed2005

Comparison of additional intraocular pressure-lowering effects of latanoprost vs brimonidine in primary open-angle glaucoma patients with intraocular pressure uncontrolled by timolol-dorzolamide combination.

PURPOSE: To compare the additive intraocular pressure (IOP)-lowering effects of latanoprost 0.005% and brimonidine 0.2% in primary open-angle glaucoma (POAG) patients uncontrolled on fixed combination of timolol 0.5% and dorzolamide 2% (TDC) alone. METHODS: In all, 80 eyes of 80 POAG patients with IOP inadequately controlled by TDC were randomly assigned to receive either latanoprost 0.005% or brimonidine 0.2%. IOP measurements were recorded at 1000 (peak effect) and 1600 (trough effect) on day 0 (baseline) and at 1 and 3 months. At each stage and time point, the mean IOP reductions from baseline were evaluated for both groups, and success rates (minimum 15% reduction) were determined. RESULTS: At baseline, the mean peak/trough IOPs with TDC were 20.2/21.6 and 19.9/21.4 mmHg in latanoprost and brimonidine groups, respectively. Latanoprost+TDC reduced the mean peak/trough IOP by 4.4/3.4 and 5.2/3.5 mmHg at 1 and 3 months. The corresponding values for brimonidine+TDC were 3.9/2.9 and 4.6/2.9 mmHg. Each of these results represented a significant reduction from baseline (P<0.001 for all); however, the groups' peak/trough reductions from baseline did not differ at any time point (P>0.05 for all). With the latanoprost+TDC combination, the peak/trough success rates at 1 and 3 months were 76.3%/42.1% and 77.1%/40%. The corresponding values with the brimonidine+TDC combination were 71.8%/41% and 77.7%/41.7%. There were no significant differences in the groups' success rates at any time point (P>0.05 for all). CONCLUSION: Addition of latanoprost 0.005% or brimonidine 0.2% to TDC reduces peak/trough IOPs significantly and the effects of these combinations are comparable.

Adult↗
PubMed1987

[Effect of the beta-blockers timolol and pindolol on retinal hemodynamics--a videoangiography study].

In a randomized double-blind study the effect of locally applied pindolol 1% and timolol 0.5% on ocular hemodynamics was tested in 19 subjects. The method used was videoangiography, which permits a quantitative analysis of the arterial, capillary and venous phases of retinal circulation. In addition to videoangiography, the Blue Field Entoptoscope was used for a simultaneous quantitative study of retinal microcirculation. The investigation showed a statistically significant negative effect of both beta-blockers on nearly all retinal circulation times as well as on microcirculation in the macular area. It could not be shown that ISA (intrinsic sympathomimetic activity) prevents the negative effect of the beta-blockers on retinal hemodynamics.

Angiography↗
PubMed1983

[Local anesthetic action of metipranolol as compared to timolol].

In a randomized study the local anesthetic side effects of the beta blockers Metipranolol and Timolol were compared. With the new electronic optical esthesiometer accurate, reproducible sensibility measurements are now possible. It can be shown that both beta blockers have a brief local anesthetic effect when applied to the cornea in drop form. There is also a relation between dose and effect.

Adult↗
PubMed1982

[Remanent efficiency of timolol in ocular hypertension (author's transl)].

In four ocular hypertensive patients (seven eyes) the lowering of intraocular pressure to a normal level persisted over a period of several months after gradual cessation of topical Timolol therapy. This remanent efficiency ("after-effect") could be used in treating ocular hypertension in order to prevent glaucoma damage.

Adult↗
PubMed1980

[Alteration of bronchial flow resistance due to timolol 0.25% in bronchial asthma (author's transl)].

A woman patient suffering from long-term pulmonary asthma was treated with steroids and developed a secondary glaucoma. After the first application of one drop of Timololmaleat 0,25% in the lower conjunctival sac of each eye a significant increase in bronchospasm was registered. The cause and consequences of this side-effect are discussed. Timolol is contraindicated for patients with pulmonary disease as long as a negative effect on the pulmonary system is not ruled out by pulmonary tests.

Asthma↗
PubMed1980

[Effect of long-term administration of timolol eye drops in open-angle glaucoma (author's transl)].

The authors report on ten patients with unstabilized open-angle glaucoma who were treated for up to six months with Timolol eye drops. A significant lowering of intraocular pressure was recorded throughout the treatment period. There was no evidence of deterioration of visual field or acuity. Subjective tolerance was good except in one patient who suffered temporarily from slight tachycardia.

Aged↗
PubMed2001

A reverse microemulsion polymerization method for preparation of bioadhesive polyacrylic acid nanoparticles for mucosal drug delivery: loading and release of timolol maleate.

Polyacrylic acid nanoparticles were successfully synthesized using a reverse microemulsion polymerization process. They had a narrow size range, averaging approximately 50 nm, and were stable in buffer. The particles were isolated and lyophilized in dry powder form, and were redispersible as individual particles in buffer. The drug timolol maleate was loaded into the nanoparticles from aqueous drug solutions and, when the drug-loaded particles were dispersed in a phosphate buffer solution, the drug slowly released over several hours from the nanoparticles.

Acrylic Resins↗
PubMed1987

Systemic side effects from ophthalmic timolol and their prevention.

Topically applied ophthalmic drugs can occasionally produce adverse systemic effects due to systemic absorption of the drug or impediment of the drug's metabolism. Increasing evidence points to significant adverse systemic effects from topical ocular administration of timolol, a beta-adrenergic blocking agent marketed for the treatment of glaucoma. Various methods to decrease or avoid unwanted systemic effects from eyedrops are discussed, including avoidance of overdosage and how to apply eye medications.

Absorption↗
PubMed1989

Measurement of aqueous humor flow following scleral injection of sulfacetamide as marker: effect of methazolamide, timolol, and pilocarpine.

A simple technique for rapid determination of the flow of aqueous humor (AH) in rabbits is described. Data from control eyes and eyes treated with known inhibitors of aqueous humor production are presented as evidence of the suitability of the technique for comparing the influence of other drugs on aqueous flow. The flow measurement depends on marker dilution by fluid turnover during the first 30 min after 5 microliters marker solution is delivered to the anterior chamber. This is done by passing a needle through the sclera and behind the iris. The advantage of this route is that it permits withdrawal of the needle after delivery without leakage of marker or aqueous humor. Sulfacetamide (SAC), a sulfonamide with low lipid solubility and pKa 5.4, is the marker of flow used here. Control flow data from SAC, fluorescein (FL), reactive blue-2, and 14C-inulin as markers were compared. The control flow measured with SAC in two independent groups is 3.91 and 3.40 microliters/min or 3.69 +/- 0.37 S.E. overall. The data show that inhibition of carbonic anhydrase (CA) in ciliary processes by systemic methazolamide reduces flow 38%. Topical timolol reduces flow 35%. Pilocarpine, which is known to decrease IOP largely by increasing outflow facility, did not significantly reduce flow. This system for measuring AH flow allows rapid accumulation of data for topical, intracameral or systemic treatments.

Animals↗
PubMed1995

Intraocular pressure after a two-week washout following long-term timolol or levobunolol.

The effect on intraocular pressure (IOP) of a 2-week washout following long-term ocular therapy with topical levobunolol or timolol for an average period of 30 months was investigated in 20 patients (11 whites and 9 blacks) with early primary open-angle glaucoma or ocular hypertensive glaucoma suspect status. The 2-week washout IOP was significantly lower than the pretreatment baseline IOP in the total 20 patients (P < 0.001), and in the 9 black patients (P = 0.004), but not in the 11 white patients (P = 0.065). However, the washout IOP was found to be significantly lower than the baseline IOP in the 5 whites with brown irides (P = 0.024) but not in the 6 whites with blue irides (P = 0.574). Thus, the 2-week washout following long-term ocular therapy with a topical beta 1-, beta 2-blocker appears insufficient to restore IOP to the pretreatment baseline level in blacks and in the whites with brown irides, whereas it may be adequate in the majority of the whites with blue irides.

Administration, Topical↗
PubMed1983

Central haemodynamic effects of beta blockers in hypertension. A comparison between atenolol, metoprolol, timolol, penbutolol, alprenolol pindolol and bunitrolol.

While it is well established that the acute haemodynamic effects of the beta blockers used in antihypertensive therapy vary considerably, it is still uncertain if this is true during chronic treatment. We have studied seven different beta blockers (one year follow-up): atenolol and metoprolol (cardioselective, without ISA), timolol (non-cardioselective, without ISA), and penbutolol, bunitrolol, alprenolol and pindolol (non-cardioselective, with different degrees of ISA). All drugs induced statistically significant reductions in heart rate (HR), cardiac output (CO) and blood pressure (BP) at rest as well as during exercise. During 100 and 150 W exercise CO and HR were generally decreased by 20-25% on beta blockers without ISA, less on beta blockers with strong ISA. Only in very few patients did total peripheral resistance (TPR) fall more than 10% below pre-treatment level both at rest and during exercise and TPR was not significantly reduced below pre-treatment level in any series. Drugs with combined beta-blocking and vasodilating (or alpha-blocking) properties (prizidilol and labetalol) induced clear reduction in TRP. HR was reduced, but since SI increased there was less reduction in CO on labetalol than on pure beta blockers and actually a small increase in CO on prizidilol.

Adrenergic beta-Antagonists↗
PubMed1992

Effects of timolol ophthalmic solution on the intra-ocular pressure rise induced by suxamethonium and tracheal intubation.

Thirty patients received topical application of either timolol ophthalmic solution 0.25%, or normal saline, 2 h before elective ophthalmic surgery in a double-blind study. The responses to suxamethonium and tracheal intubation were compared by measuring intra-ocular pressure before induction of anaesthesia, 1 min after administration of thiopentone 2-4 mg.kg-1, 1 min after administration of suxamethonium 1 mg.kg-1, and 1, 2.5 and 5 min after tracheal intubation. There was no significant difference between the groups.

Adult↗