Browsing by Subject "Betaxolol"

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  • Fayyaz, Anam; Vellonen, Kati-Sisko; Ranta, Veli-Pekka; Toropainen, Elisa; Reinisalo, Mika; Valtari, Annika; Puranen, Jooseppi; Ricci, Giuseppe D'Amico; Heikkinen, Emma M.; Gardner, Iain; Ruponen, Marika; Urtti, Arto; Jamei, Masoud; Amo, Eva M. del (2021)
    Quantitative understanding of pharmacokinetics of topically applied ocular drugs requires more research to further understanding and to eventually allow predictive in silico models to be developed. To this end, a topical cocktail of betaxolol, timolol and atenolol was instilled on albino rabbit eyes. Tear fluid, corneal epithelium, corneal stroma with endothelium, bulbar conjunctiva, anterior sclera, iris-ciliary body, lens and vitreous samples were collected and analysed using LC-MS/MS. Iris-ciliary body was also analysed after intracameral cocktail injection. Non-compartmental analysis was utilized to estimate the pharmacokinetics parameters. The most lipophilic drug, betaxolol, presented the highest exposure in all tissues except for tear fluid after topical administration, followed by timolol and atenolol. For all drugs, iris-ciliary body concentrations were higher than that of the aqueous humor. After topical instillation the most hydrophilic drug, atenolol, had 3.7 times higher AUCiris-ciliary body than AUCaqueous humor, whereas the difference was 1.4 and 1.6 times for timolol and betaxolol, respectively. This suggests that the non-corneal route (conjunctival-scleral) was dominating the absorption of atenolol, while the corneal route was more important for timolol and betaxolol. The presented data increase understanding of ocular pharmacokinetics of a cocktail of drugs and provide data that can be used for quantitative modeling and simulation.
  • Fayyaz, Anam; Ranta, Veli-Pekka; Toropainen, Elisa; Vellonen, Kati-Sisko; Valtari, Annika; Puranen, Jooseppi; Ruponen, Marika; Gardner, Iain; Urtti, Arto; Jamei, Masoud; del Amo, Eva M. (2020)
    Ocular bioavailability after eye drops administration is an important, but rarely determined, pharmacokinetic parameter. In this study, we measured the pharmacokinetics of a cocktail of three beta blockers after their topical administration into the albino rabbit eye. Samples from aqueous humour were analysed with LC-MS/MS. The pharmacokinetic parameters were estimated using compartmental and non-compartmental analyses. The ocular bioavailability was covering broad range of values: atenolol (0.07 %), timolol (1.22%, 1.51%) and betaxolol (3.82%, 4.31%). Absolute ocular bioavailability presented a positive trend with lipophilicity and the values showed approximately 60-fold range. The generated data enhances our understanding for ocular pharmacokinetics of drugs and may be utilized in pharmacokinetic model building in ophthalmic drug development.