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Matti K. Saari - One of the best experts on this subject based on the ideXlab platform.
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plasma and aqueous humour concentrations and systemic effects of topical Betaxolol and timolol in man
Acta Ophthalmologica, 2009Co-Authors: Marja‐liisa Vuori, Timo Kaila, Timo Alimelkkila, Esko Iisalo, Matti K. SaariAbstract:Plasma and aqueous humour concentrations and systemic effects of timolol and Betaxolol were studied after ocular administration in 45 patients scheduled for extracapsular cataract extraction and intraocular lens implantation. The patients were divided randomly into three groups and received 40 μl of either 0.5% Betaxolol, 0.25% timolol or placebo into the lower cul-de-sacs of both eyes. Blood samples were collected over a period of 4 h and blood pressure and heart rate were monitored during the study. Aqueous humour samples were aspirated at the beginning of the operation. Plasma and aqueous humour concentrations of timolol and Betaxolol were analyzed using a sensitive radioreceptor assay. The mean plasma concentrations of Betaxolol were lower than those of timolol. The concentration of Betaxolol in the aqueous humour was twice as high as the concentration of timolol. Both drugs produced a significant decrease in heart rate. In the timolol group a decrease in heart rate was found 15 min after drug administration, and in the Betaxolol group after one hour.
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s1 and s2 antagonist activity of topically applied Betaxolol and timolol in the systemic circulation
Acta Ophthalmologica, 2009Co-Authors: Marja-liisa Vuori, Esko Lisalo, Timo Kaila, Timo Alimelkkila, Matti K. SaariAbstract:The beta 1- and beta 2-antagonist activity of Betaxolol and timolol in the systemic circulation was studied ex-vivo after their ocular administration in thirty patients during cataract surgery. The patients received 40 microliters of 0.5% Betaxolol or 0.25% timolol into the lower cul-de-sacs of both eyes. Blood samples were collected up to four h after instillation of the doses. Plasma concentrations of Betaxolol and timolol were analyzed using a radioreceptor assay. The ex-vivo-beta 1-and beta 2-receptor occupancies corresponding drug plasma levels were calculated using radioligand binding techniques. The extent of beta 1-receptor occupancy of Betaxolol in the systemic circulation was less than 20% and its beta 2-receptor occupancy was negligible. The extent of beta 1-receptor occupancy of timolol was about 65% and its beta 2-receptor occupancy about 80%. Because receptor occupancy is the basis of antagonist activity of beta-blocking agents, this study shows that the beta 1-antagonist activity of Betaxolol in the systemic circulation is much less than that of timolol, and that its beta 2-antagonist activity is negligible. The study suggests that the reported side effects of Betaxolol in patients with obstructive pulmonary diseases are not mediated via its beta 2-receptor blocking properties.
Timo Kaila - One of the best experts on this subject based on the ideXlab platform.
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plasma and aqueous humour concentrations and systemic effects of topical Betaxolol and timolol in man
Acta Ophthalmologica, 2009Co-Authors: Marja‐liisa Vuori, Timo Kaila, Timo Alimelkkila, Esko Iisalo, Matti K. SaariAbstract:Plasma and aqueous humour concentrations and systemic effects of timolol and Betaxolol were studied after ocular administration in 45 patients scheduled for extracapsular cataract extraction and intraocular lens implantation. The patients were divided randomly into three groups and received 40 μl of either 0.5% Betaxolol, 0.25% timolol or placebo into the lower cul-de-sacs of both eyes. Blood samples were collected over a period of 4 h and blood pressure and heart rate were monitored during the study. Aqueous humour samples were aspirated at the beginning of the operation. Plasma and aqueous humour concentrations of timolol and Betaxolol were analyzed using a sensitive radioreceptor assay. The mean plasma concentrations of Betaxolol were lower than those of timolol. The concentration of Betaxolol in the aqueous humour was twice as high as the concentration of timolol. Both drugs produced a significant decrease in heart rate. In the timolol group a decrease in heart rate was found 15 min after drug administration, and in the Betaxolol group after one hour.
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Plasma and aqueous humour concentrations and systemic effects of topical Betaxolol and timolol in man.
Acta Ophthalmologica, 2009Co-Authors: Marja‐liisa Vuori, Timo Kaila, Esko Iisalo, Timo Ali‐melkkilä, K. Matti SaariAbstract:Plasma and aqueous humour concentrations and systemic effects of timolol and Betaxolol were studied after ocular administration in 45 patients scheduled for extracapsular cataract extraction and intraocular lens implantation. The patients were divided randomly into three groups and received 40 microliters of either 0.5% Betaxolol, 0.25% timolol or placebo into the lower cul-de-sacs of both eyes. Blood samples were collected over a period of 4 h and blood pressure and heart rate were monitored during the study. Aqueous humour samples were aspirated at the beginning of the operation. Plasma and aqueous humour concentrations of timolol and Betaxolol were analyzed using a sensitive radioreceptor assay. The mean plasma concentrations of Betaxolol were lower than those of timolol. The concentration of Betaxolol in the aqueous humour was twice as high as the concentration of timolol. Both drugs produced a significant decrease in heart rate. In the timolol group a decrease in heart rate was found 15 min after drug administration, and in the Betaxolol group after one hour.
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Concentrations and antagonist activity of topically applied Betaxolol in aqueous humour
Acta Ophthalmologica, 2009Co-Authors: Marja‐liisa Vuori, Esko Lisalo, Timo Kaila, K. Matti SaariAbstract:. Aqueous humour concentrations and antagonist activity of Betaxolol were studied after ocular administration in forty-five patients scheduled for cataract surgery. The patients were randomly devided into five groups and received 40μl of 0.5% Betaxolol into the lower cul-de-sac of one eye. In groups I, II, III and IV the drug was instilled 5–6, 12, 24 and 48 h, respectively, before surgery, into the eye to be operated, and in group V 4 h before surgery into the contralateral eye. Aqueous humour samples were aspirated at the beginning of the operation. Aqueous humour concentrations of Betaxolol were analyzed using a radioreceptor assay, and the ex-vivo-s1- and s2-receptor occupancies of Betaxolol were calculated. The highest concentration of Betaxolol in aqueous humour was found 5–6 hours after instillation of the drug. Topical Betaxolol was found to stay in aqueous humour for 48 h, a much longer time than the recommended interval of dosage. Betaxolol s1-receptor occupancy was 99–95% during the study, but also s2-receptor occupancy was significant (52%) 24 h after instillation of the drug. Because receptor occupancy is the basis of antagonist activity, the role of s2-receptor blocking effect of Betaxolol in lowering intraocular pressure cannot be excluded.
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Concentrations and antagonist activity of topically applied Betaxolol in aqueous humour.
Acta Ophthalmologica, 2009Co-Authors: Marja‐liisa Vuori, Esko Lisalo, Timo Kaila, K. Matti SaariAbstract:Aqueous humour concentrations and antagonist activity of Betaxolol were studied after ocular administration in forty-five patients scheduled for cataract surgery. The patients were randomly divided into five groups and received 40 microliters of 0.5% Betaxolol into the lower cul-de-sac of one eye. In groups I, II, III and IV the drug was instilled 5-6, 12, 24 and 48 h, respectively, before surgery, into the eye to be operated, and in group V 4 h before surgery into the contralateral eye. Aqueous humour samples were aspirated at the beginning of the operation. Aqueous humour concentrations of Betaxolol were analyzed using a radioreceptor assay, and the ex-vivo-beta 1- and beta 2-receptor occupancies of Betaxolol were calculated. The highest concentration of Betaxolol in aqueous humour was found 5-6 hours after instillation of the drug. Topical Betaxolol was found to stay in aqueous humour for 48 h, a much longer time than the recommended interval of dosage. Betaxolol beta 1-receptor occupancy was 99-95% during the study, but also beta 2-receptor occupancy was significant (52%) 24 h after instillation of the drug. Because receptor occupancy is the basis of antagonist activity, the role of beta 2-receptor blocking effect of Betaxolol in lowering intraocular pressure cannot be excluded.
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ß1‐ and ß2‐antagonist activity of topically applied Betaxolol and timolol in the systemic circulation
Acta Ophthalmologica, 2009Co-Authors: Marja-liisa Vuori, Esko Lisalo, Timo Kaila, Timo Ali‐melkkilä, K. Matti SaariAbstract:The beta 1- and beta 2-antagonist activity of Betaxolol and timolol in the systemic circulation was studied ex-vivo after their ocular administration in thirty patients during cataract surgery. The patients received 40 microliters of 0.5% Betaxolol or 0.25% timolol into the lower cul-de-sacs of both eyes. Blood samples were collected up to four h after instillation of the doses. Plasma concentrations of Betaxolol and timolol were analyzed using a radioreceptor assay. The ex-vivo-beta 1-and beta 2-receptor occupancies corresponding drug plasma levels were calculated using radioligand binding techniques. The extent of beta 1-receptor occupancy of Betaxolol in the systemic circulation was less than 20% and its beta 2-receptor occupancy was negligible. The extent of beta 1-receptor occupancy of timolol was about 65% and its beta 2-receptor occupancy about 80%. Because receptor occupancy is the basis of antagonist activity of beta-blocking agents, this study shows that the beta 1-antagonist activity of Betaxolol in the systemic circulation is much less than that of timolol, and that its beta 2-antagonist activity is negligible. The study suggests that the reported side effects of Betaxolol in patients with obstructive pulmonary diseases are not mediated via its beta 2-receptor blocking properties.
Marja-liisa Vuori - One of the best experts on this subject based on the ideXlab platform.
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s1 and s2 antagonist activity of topically applied Betaxolol and timolol in the systemic circulation
Acta Ophthalmologica, 2009Co-Authors: Marja-liisa Vuori, Esko Lisalo, Timo Kaila, Timo Alimelkkila, Matti K. SaariAbstract:The beta 1- and beta 2-antagonist activity of Betaxolol and timolol in the systemic circulation was studied ex-vivo after their ocular administration in thirty patients during cataract surgery. The patients received 40 microliters of 0.5% Betaxolol or 0.25% timolol into the lower cul-de-sacs of both eyes. Blood samples were collected up to four h after instillation of the doses. Plasma concentrations of Betaxolol and timolol were analyzed using a radioreceptor assay. The ex-vivo-beta 1-and beta 2-receptor occupancies corresponding drug plasma levels were calculated using radioligand binding techniques. The extent of beta 1-receptor occupancy of Betaxolol in the systemic circulation was less than 20% and its beta 2-receptor occupancy was negligible. The extent of beta 1-receptor occupancy of timolol was about 65% and its beta 2-receptor occupancy about 80%. Because receptor occupancy is the basis of antagonist activity of beta-blocking agents, this study shows that the beta 1-antagonist activity of Betaxolol in the systemic circulation is much less than that of timolol, and that its beta 2-antagonist activity is negligible. The study suggests that the reported side effects of Betaxolol in patients with obstructive pulmonary diseases are not mediated via its beta 2-receptor blocking properties.
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ß1‐ and ß2‐antagonist activity of topically applied Betaxolol and timolol in the systemic circulation
Acta Ophthalmologica, 2009Co-Authors: Marja-liisa Vuori, Esko Lisalo, Timo Kaila, Timo Ali‐melkkilä, K. Matti SaariAbstract:The beta 1- and beta 2-antagonist activity of Betaxolol and timolol in the systemic circulation was studied ex-vivo after their ocular administration in thirty patients during cataract surgery. The patients received 40 microliters of 0.5% Betaxolol or 0.25% timolol into the lower cul-de-sacs of both eyes. Blood samples were collected up to four h after instillation of the doses. Plasma concentrations of Betaxolol and timolol were analyzed using a radioreceptor assay. The ex-vivo-beta 1-and beta 2-receptor occupancies corresponding drug plasma levels were calculated using radioligand binding techniques. The extent of beta 1-receptor occupancy of Betaxolol in the systemic circulation was less than 20% and its beta 2-receptor occupancy was negligible. The extent of beta 1-receptor occupancy of timolol was about 65% and its beta 2-receptor occupancy about 80%. Because receptor occupancy is the basis of antagonist activity of beta-blocking agents, this study shows that the beta 1-antagonist activity of Betaxolol in the systemic circulation is much less than that of timolol, and that its beta 2-antagonist activity is negligible. The study suggests that the reported side effects of Betaxolol in patients with obstructive pulmonary diseases are not mediated via its beta 2-receptor blocking properties.
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Plasma concentration of topically applied Betaxolol in elderly glaucoma patients.
Journal of Ocular Pharmacology and Therapeutics, 2001Co-Authors: Elina Vainio-jylhä, Marja-liisa Vuori, Kaija Pyykkö, Risto HuupponenAbstract:Our aim was to study the concentration of Betaxolol in plasma after its topical ocular use during the normal 12 hr dosing interval. Twenty microliters of Betaxolol 0.5% solution were applied into b...
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The favorable effect of topical Betaxolol and timolol on glaucomatous visual fields: a 2-year follow-up study.
Graefe's Archive for Clinical and Experimental Ophthalmology, 1999Co-Authors: E. Vainio-jylhä, Marja-liisa VuoriAbstract:· Background: It has been suggested that β-adrenergic antagonists might have mechanisms of action other than ocular hypotensive effects affecting the visual function in glaucoma patients and that Betaxolol might protect the visual field better than others. A randomized, double-blind study was conducted to compare the effects of Betaxolol and timolol on visual fields of glaucoma patients. · Methods: Sixty-four glaucoma patients were treated with either 0.5% Betaxolol or 0.25% timolol eyedrops twice daily. The Octopus visual field performance was followed up for 2 years and analyzed to find diffuse and localized changes. We analyzed the change in the mean sensitivity (MS) and performed a cluster analysis and clinical assessment of the visual fields in both treatment groups. · Results: The mean sensitivity (MS) improved significantly and equally in both treatment groups. There was a tendency towards more improved clusters in the Betaxolol group than in the timolol group and more worsened cluster in the timolol group than in the Betaxolol group, but the difference was not statistically significant. The clinical assessment also showed no statistically significant difference between the two groups. · Conclusion: In the present study both Betaxolol and timolol had a favorable effect on the visual fields of glaucoma patients. There was no statistically significant difference between Betaxolol- and timolol-treated patients either in the change in mean retinal sensitivity or in the change in localized scotomatous areas.
Marja‐liisa Vuori - One of the best experts on this subject based on the ideXlab platform.
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plasma and aqueous humour concentrations and systemic effects of topical Betaxolol and timolol in man
Acta Ophthalmologica, 2009Co-Authors: Marja‐liisa Vuori, Timo Kaila, Timo Alimelkkila, Esko Iisalo, Matti K. SaariAbstract:Plasma and aqueous humour concentrations and systemic effects of timolol and Betaxolol were studied after ocular administration in 45 patients scheduled for extracapsular cataract extraction and intraocular lens implantation. The patients were divided randomly into three groups and received 40 μl of either 0.5% Betaxolol, 0.25% timolol or placebo into the lower cul-de-sacs of both eyes. Blood samples were collected over a period of 4 h and blood pressure and heart rate were monitored during the study. Aqueous humour samples were aspirated at the beginning of the operation. Plasma and aqueous humour concentrations of timolol and Betaxolol were analyzed using a sensitive radioreceptor assay. The mean plasma concentrations of Betaxolol were lower than those of timolol. The concentration of Betaxolol in the aqueous humour was twice as high as the concentration of timolol. Both drugs produced a significant decrease in heart rate. In the timolol group a decrease in heart rate was found 15 min after drug administration, and in the Betaxolol group after one hour.
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Plasma and aqueous humour concentrations and systemic effects of topical Betaxolol and timolol in man.
Acta Ophthalmologica, 2009Co-Authors: Marja‐liisa Vuori, Timo Kaila, Esko Iisalo, Timo Ali‐melkkilä, K. Matti SaariAbstract:Plasma and aqueous humour concentrations and systemic effects of timolol and Betaxolol were studied after ocular administration in 45 patients scheduled for extracapsular cataract extraction and intraocular lens implantation. The patients were divided randomly into three groups and received 40 microliters of either 0.5% Betaxolol, 0.25% timolol or placebo into the lower cul-de-sacs of both eyes. Blood samples were collected over a period of 4 h and blood pressure and heart rate were monitored during the study. Aqueous humour samples were aspirated at the beginning of the operation. Plasma and aqueous humour concentrations of timolol and Betaxolol were analyzed using a sensitive radioreceptor assay. The mean plasma concentrations of Betaxolol were lower than those of timolol. The concentration of Betaxolol in the aqueous humour was twice as high as the concentration of timolol. Both drugs produced a significant decrease in heart rate. In the timolol group a decrease in heart rate was found 15 min after drug administration, and in the Betaxolol group after one hour.
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Concentrations and antagonist activity of topically applied Betaxolol in aqueous humour
Acta Ophthalmologica, 2009Co-Authors: Marja‐liisa Vuori, Esko Lisalo, Timo Kaila, K. Matti SaariAbstract:. Aqueous humour concentrations and antagonist activity of Betaxolol were studied after ocular administration in forty-five patients scheduled for cataract surgery. The patients were randomly devided into five groups and received 40μl of 0.5% Betaxolol into the lower cul-de-sac of one eye. In groups I, II, III and IV the drug was instilled 5–6, 12, 24 and 48 h, respectively, before surgery, into the eye to be operated, and in group V 4 h before surgery into the contralateral eye. Aqueous humour samples were aspirated at the beginning of the operation. Aqueous humour concentrations of Betaxolol were analyzed using a radioreceptor assay, and the ex-vivo-s1- and s2-receptor occupancies of Betaxolol were calculated. The highest concentration of Betaxolol in aqueous humour was found 5–6 hours after instillation of the drug. Topical Betaxolol was found to stay in aqueous humour for 48 h, a much longer time than the recommended interval of dosage. Betaxolol s1-receptor occupancy was 99–95% during the study, but also s2-receptor occupancy was significant (52%) 24 h after instillation of the drug. Because receptor occupancy is the basis of antagonist activity, the role of s2-receptor blocking effect of Betaxolol in lowering intraocular pressure cannot be excluded.
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Concentrations and antagonist activity of topically applied Betaxolol in aqueous humour.
Acta Ophthalmologica, 2009Co-Authors: Marja‐liisa Vuori, Esko Lisalo, Timo Kaila, K. Matti SaariAbstract:Aqueous humour concentrations and antagonist activity of Betaxolol were studied after ocular administration in forty-five patients scheduled for cataract surgery. The patients were randomly divided into five groups and received 40 microliters of 0.5% Betaxolol into the lower cul-de-sac of one eye. In groups I, II, III and IV the drug was instilled 5-6, 12, 24 and 48 h, respectively, before surgery, into the eye to be operated, and in group V 4 h before surgery into the contralateral eye. Aqueous humour samples were aspirated at the beginning of the operation. Aqueous humour concentrations of Betaxolol were analyzed using a radioreceptor assay, and the ex-vivo-beta 1- and beta 2-receptor occupancies of Betaxolol were calculated. The highest concentration of Betaxolol in aqueous humour was found 5-6 hours after instillation of the drug. Topical Betaxolol was found to stay in aqueous humour for 48 h, a much longer time than the recommended interval of dosage. Betaxolol beta 1-receptor occupancy was 99-95% during the study, but also beta 2-receptor occupancy was significant (52%) 24 h after instillation of the drug. Because receptor occupancy is the basis of antagonist activity, the role of beta 2-receptor blocking effect of Betaxolol in lowering intraocular pressure cannot be excluded.
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Aqueous humour concentration and the intraocular pressure-lowering effect of topical Betaxolol before cataract surgery.
European Journal of Clinical Pharmacology, 1998Co-Authors: Elina Vainio-jylhä, Marja‐liisa Vuori, Timo Kaila, Risto HuupponenAbstract:Objective: The aim was to study the relationship between aqueous humour Betaxolol concentration and intraocular pressure (IOP). Methods: In this double-blind, randomized study, we administered Betaxolol (a) or placebo (b) ocularly to 131 patients scheduled for cataract surgery. The patients were randomly divided into ten groups. In groups 1a and 1b, the drug was scheduled to be instilled 1–2 h, in groups 2a and 2b 12 h, in groups 3a and 3b 24 h, and in groups 4a and 4b 48 h before surgery. The pupil was dilated in all eyes prior to surgery. The IOP was measured with Perkins' applanation tonometer before the instillation of the drug and just before the peribulbar block. Twenty microlitres of 0.5% Betaxolol or placebo solution was instilled into the eye. IOP was also measured before instillation of the drug and after 1–2 h in undilated eyes of 20 patients, whose contralateral eye was to be operated on, to rule out the effect of pupil dilation on IOP (groups 5a and 5b). Aqueous humour Betaxolol concentrations were analysed using a radioreceptor assay. Results: Betaxolol did not decrease IOP significantly in eyes with pupillary dilation. Both Betaxolol and placebo decreased IOP significantly in patients without pupillary dilation, the effect of Betaxolol being slightly more pronounced. The Betaxolol concentration in aqueous humour was 731 ng · ml−1 in group 1a, 2.4 h after drug instillation. Measurable concentrations of Betaxolol were also detected in aqueous humour in group 4a 47.7 h after drug administration. Conclusion: No correlation between aqueous humour concentration of Betaxolol and the effect on IOP was found in eyes where the pupil was dilated before surgery. A single Betaxolol dose did not decrease IOP significantly in patients undergoing cataract surgery, but the IOP decreasing effect was, however, clearly seen in patients who did not receive mydriatic drugs. The routine use of topical Betaxolol prior to cataract surgery to decrease IOP is not recommended.
Timo Alimelkkila - One of the best experts on this subject based on the ideXlab platform.
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plasma and aqueous humour concentrations and systemic effects of topical Betaxolol and timolol in man
Acta Ophthalmologica, 2009Co-Authors: Marja‐liisa Vuori, Timo Kaila, Timo Alimelkkila, Esko Iisalo, Matti K. SaariAbstract:Plasma and aqueous humour concentrations and systemic effects of timolol and Betaxolol were studied after ocular administration in 45 patients scheduled for extracapsular cataract extraction and intraocular lens implantation. The patients were divided randomly into three groups and received 40 μl of either 0.5% Betaxolol, 0.25% timolol or placebo into the lower cul-de-sacs of both eyes. Blood samples were collected over a period of 4 h and blood pressure and heart rate were monitored during the study. Aqueous humour samples were aspirated at the beginning of the operation. Plasma and aqueous humour concentrations of timolol and Betaxolol were analyzed using a sensitive radioreceptor assay. The mean plasma concentrations of Betaxolol were lower than those of timolol. The concentration of Betaxolol in the aqueous humour was twice as high as the concentration of timolol. Both drugs produced a significant decrease in heart rate. In the timolol group a decrease in heart rate was found 15 min after drug administration, and in the Betaxolol group after one hour.
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s1 and s2 antagonist activity of topically applied Betaxolol and timolol in the systemic circulation
Acta Ophthalmologica, 2009Co-Authors: Marja-liisa Vuori, Esko Lisalo, Timo Kaila, Timo Alimelkkila, Matti K. SaariAbstract:The beta 1- and beta 2-antagonist activity of Betaxolol and timolol in the systemic circulation was studied ex-vivo after their ocular administration in thirty patients during cataract surgery. The patients received 40 microliters of 0.5% Betaxolol or 0.25% timolol into the lower cul-de-sacs of both eyes. Blood samples were collected up to four h after instillation of the doses. Plasma concentrations of Betaxolol and timolol were analyzed using a radioreceptor assay. The ex-vivo-beta 1-and beta 2-receptor occupancies corresponding drug plasma levels were calculated using radioligand binding techniques. The extent of beta 1-receptor occupancy of Betaxolol in the systemic circulation was less than 20% and its beta 2-receptor occupancy was negligible. The extent of beta 1-receptor occupancy of timolol was about 65% and its beta 2-receptor occupancy about 80%. Because receptor occupancy is the basis of antagonist activity of beta-blocking agents, this study shows that the beta 1-antagonist activity of Betaxolol in the systemic circulation is much less than that of timolol, and that its beta 2-antagonist activity is negligible. The study suggests that the reported side effects of Betaxolol in patients with obstructive pulmonary diseases are not mediated via its beta 2-receptor blocking properties.