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Betaxolol is commonly used to manage glaucoma in clinical practice. However, its long-term use may damage the cornea. Thus, the cytotoxicity and mechanisms of betaxolol in human corneal stromal cells (HCSCs) warrant further study. In this study, we used in vitro HCSCs and in vivo rabbit corneal models to investigate betaxolol cytotoxic effects and mechanism of action. At near-clinical concentrations (0.28% and 0.14%), betaxolol inhibited caspase-8 activity, activated receptor-interacting protein kinase (RIPK)1, RIPK3, and mixed-spectrum kinase-like domain (MLKL), and phosphorylated MLKL to induce necroptosis in HCSCs. Similarly, moderate concentrations of betaxolol (0.07%-0.0175%) activated caspase-8 to trigger the exogenous apoptotic pathway. Through the intrinsic apoptotic pathway, betaxolol upregulated the expression of Bcl-2 family apoptotic proteins Bax and Bad and downregulated that of anti-apoptotic proteins Bcl-2 and Bcl-xL. This subsequently disrupted the mitochondrial membrane potential and cytoplasmic transfer of cytochrome c and apoptosis-inducing factor, activated caspase-9, and induced apoptosis in HCSCs. Furthermore, continuous treatment with low betaxolol concentrations (0.00875%) for three generations of HCSCs prevented apoptosis by promoting the expression of Bcl-xL and suppressing that of Bax. However, its toxic effects initiated cellular senescence by increasing reactive oxygen species, leading to the disruption of energy metabolism and DNA damage. Finally, clinical concentrations of betaxolol had a pro-apoptotic effect on rabbit corneal stromal cells in vivo. These results suggest that betaxolol induces cytotoxicity in a concentration-dependent manner in HCSCs, and that caspase-8 and Bcl-2 family proteins may be critical switches in the conversion of different HCSC death mechanisms.
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Betaxolol , Necroptosis , Animales , Humanos , Conejos , Betaxolol/metabolismo , Betaxolol/farmacología , Caspasa 8/metabolismo , Proteína X Asociada a bcl-2/metabolismo , Apoptosis , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo , Células del Estroma/metabolismoRESUMEN
With significant human and economic losses, increasing bacterial resistance is a serious global threat to human life. Due to their high efficacy, broad spectrum, and cost-effectiveness, beta-lactams are widely used in the clinical management of bacterial infection. The emergence and wide spread of New Delhi metallo-ß-lactamase (NDM-1), which can effectively inactivate ß-lactams, has posed a challenge in the design of effective new antimicrobial treatments. Medicine repurposing is now an important tool in the development of new alternative medicines. We present a known glaucoma therapeutic, betaxolol (BET), which with a 50% inhibitory concentration (IC50) of 19.3 ± 0.9 µM significantly inhibits the hydrolytic activity of the NDM-1 enzyme and may represent a potential NDM-1 enzyme inhibitor. BET combined with meropenem (MEM) showed bactericidal synergism in vitro. The efficacy of BET was further evaluated against systemic bacterial infections in BALB/c mice. The results showed that BET+MEM decreased the numbers of leukocytes and inflammatory factors in peripheral blood, as well as the organ bacterial load and pathological damage. Molecular docking and kinetic simulations showed that BET can form hydrogen bonds and hydrophobic interactions directly with key amino acid residues in the NDM-1 active site. Thus, we demonstrated that BET inhibited NDM-1 by competitively binding to it and that it can be developed in combination with MEM as a new therapy for the management of infections caused by medicine-resistant bacteria.
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Betaxolol , Escherichia coli , Humanos , Animales , Ratones , Meropenem/farmacología , Simulación del Acoplamiento Molecular , AntiinflamatoriosRESUMEN
Introduction: Glaucoma is a chronic disease that requires long-term adherence to treatment. Topical application of conventional eye drops results in substantial drug loss due to rapid tear turnover, with poor drug bioavailability being a major challenge for efficient glaucoma treatment. We aimed to prepare the anti-glaucoma drug betaxolol hydrochloride (BH) as a novel nano-delivery system that prolonged the retention time at the ocular surface and improved bioavailability. Methods: We constructed multifunctional nanoparticles (MMt-BH-HA/CS-ED NPs) by ion cross-linking-solvent evaporation method. The particle size, zeta potential, encapsulation efficiency and drug loading of MMt-BH-HA/CS-ED NPs were physicochemically characterized. The structure of the preparations was characterized by microscopic techniques of SEM, TEM, XPS, XRD, FTIR and TGA, and evaluated for their in vitro release performance as well as adhesion properties. Its safety was investigated using irritation assays of hemolysis experiment, Draize test and histopathology examination. Precorneal retention was examined by in vivo fluorescence tracer method and pharmacokinetics in tear fluid was studied. A model of high IOP successfully induced by injection of compound carbomer solution was used to assess the IOP-lowering efficacy of the formulation, and it was proposed that micro-interactions between the formulation and the tear film would be used to analyze the behavior at the ocular surface. Results: The positively charged MMt-BH-HA/CS-ED NPs were successfully prepared with good two-step release properties, higher viscosity, and slower pre-corneal diffusion rate along with longer precorneal retention time compared to BH solution. The micro-interactions between nanoparticles and tear film converted the drug clearance from being controlled by fast aqueous layer turnover to slow mucin layer turnover, resulting in higher drug concentration on the ocular surface, providing more durable and stable IOP-lowering efficacy. Conclusion: The novel multifunctional MMt-BH-HA/CS-ED NPs can effectively reduce IOP and are suitable for the treatment of chronic disease glaucoma.
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Glaucoma , Nanopartículas , Humanos , Betaxolol , Presión Intraocular , Nanopartículas/química , Glaucoma/patología , Córnea , Tamaño de la Partícula , Portadores de Fármacos/químicaRESUMEN
BACKGROUND: Beta-blockers have gradually become an attractive option for the treatment of infantile hemangiomas. Topical application is preferred to oral administration because of their potential systemic adverse effects. The aim of this study is to investigate the effect of betaxolol in treating superficial infantile hemangioma. METHODS: Seventy-four infants admitted to the First Affiliated Hospital of Xinjiang Medical University from 2018 to 2019 were observed and recorded. Variables such as color, size, tension, and thickness were recorded monthly and evaluated using visual analog scales. Multi-factor analysis of variance with repeated measurements and the non-parametric Kruskal-Wallis H test were used to compare clinical effectiveness across the different groups. RESULTS: After 6 months of treatment, 33.78% (25/74) showed excellent results, 55.41% (41/74) had good responses, 8.11% (6/74) had moderate responses, and 2.70% (2/74) had poor responses. Local discomfort and systemic complications were not found. There was no significant difference in gender and location of occurrence among groups (p > 0.05), and the effect of topical application of betaxolol was optimum in the children aged 0-3 months (p = 0.002). None of three age groups had statistically significant difference in heart rate and blood pressure after accepting treatment (1 month, p = 0.618; 4 months, p = 0.138; 6 months, p = 0.757). CONCLUSIONS: Our study showed that topical administration of betaxolol was effective and well tolerated for superficial infantile hemangiomas, particularly in the early proliferative stage. However, its safety and efficacy need further research.
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Hemangioma Capilar , Hemangioma , Neoplasias Cutáneas , Lactante , Niño , Humanos , Timolol/efectos adversos , Hemangioma/tratamiento farmacológico , Proyectos Piloto , Betaxolol/uso terapéutico , Hemangioma Capilar/tratamiento farmacológico , Antagonistas Adrenérgicos beta/uso terapéutico , Resultado del Tratamiento , Neoplasias Cutáneas/tratamiento farmacológicoRESUMEN
CLINICAL RELEVANCE: Posterior capsule opacification is a common late complication of cataract surgery. Posterior capsule opening with Nd:YAG laser, which is the standard treatment, may cause transient elevation of intraocular pressure (IOP). BACKGROUND: To evaluate the efficacy of betaxolol 0.|5% compared to brimonidine 0.2%, in prevention of intraocular pressure increase after Nd:YAG Laser posterior capsulotomy. METHODS: In a double masked randomised clinical trial, 38 eyes from 38 pseudophakic patients over 21 years of age who had significant posterior capsule opacification after phacoemulsification were randomly assigned to receive either betaxolol 0.|5% (18 eyes) or brimonidine 0.|2% (20 eyes) one hour before Nd:YAG Laser posterior capsulotomy.| Exclusion criteria were: glaucoma or history of glaucoma surgery, active uveitis, active ocular infection, pregnancy, unstable cardiovascular condition and severe asthma and lung diseases. Intraocular pressure was measured by Goldmann applanation tonometry, 1 hour before applying the laser and 4 hours after the laser application. RESULTS: There was no statistically significant difference between the two groups regarding the baseline mean IOP and the 4-hour post-laser mean IOP. There was a statistically significant decrease in the 4-hour post-laser mean IOP as compared to the baseline mean IOP in each group. The mean IOP change in the betaxolol group, was -2.39 ± 1.79 mm Hg and in the brimonidine group was -4.25 ± 2.20 mm Hg. The difference was statistically significant (P = 0.007). None of the patients experienced clinically significant IOP increase (≥5 mm Hg) in either group. CONCLUSION: Use of a single topical dose of betaxolol 0.5% and brimonidine 0.2%, 1 hour before laser treatment, can prevent significant acute IOP increase after Nd:YAG laser posterior capsulotomy, and betaxolol may provide a new alternative for prophylactic use.
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Opacificación Capsular , Glaucoma , Cápsula del Cristalino , Hipertensión Ocular , Humanos , Presión Intraocular , Tartrato de Brimonidina/uso terapéutico , Betaxolol/uso terapéutico , Opacificación Capsular/cirugía , Hipertensión Ocular/etiología , Hipertensión Ocular/prevención & control , Capsulotomía Posterior/efectos adversos , Glaucoma/tratamiento farmacológico , Complicaciones Posoperatorias/prevención & controlRESUMEN
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.
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Humor Acuoso/química , Atenolol , Betaxolol , Lágrimas/química , Timolol , Administración Oftálmica , Animales , Atenolol/administración & dosificación , Atenolol/farmacocinética , Betaxolol/administración & dosificación , Betaxolol/farmacocinética , Disponibilidad Biológica , Combinación de Medicamentos , Soluciones Oftálmicas/administración & dosificación , Soluciones Oftálmicas/farmacocinética , Evaluación de Resultado en la Atención de Salud , Conejos , Solubilidad , Timolol/administración & dosificación , Timolol/farmacocinética , Distribución TisularRESUMEN
Blindness and impaired vision are considered as the most troublesome health conditions leading to significant socioeconomic strains. The current study focuses on development of nanoparticulate systems (i.e., niosomes) as drug vehicles to enhance the ocular availability of betaxolol hydrochloride for management of glaucoma. Betaxolol-loaded niosomes were further laden into pH-responsive in situ forming gels to further extend precorneal retention of the drug. The niosomes were evaluated in terms of vesicle size, morphology, size distribution, surface charge and encapsulation efficiency. The optimized niosomes, comprised of Span® 40 and cholesterol at a molar ratio of 4:1, displayed particle size of 332 ± 7 nm, zeta potential of -46 ± 1 mV, and encapsulation efficiency of 69 ± 5%. The optimal nanodispersion was then incorporated into a pH-triggered in situ forming gel comprised of Carbopol® 934P and hydroxyethyl cellulose. The formed gels were translucent, pseudoplastic, mucoadhesive, and displayed a sustained in vitro drug release pattern. Upon instillation of the betaxolol-loaded niosomal gel into rabbits' eyes, a prolonged intraocular pressure reduction and significant enhancement in the relative bioavailability of betaxolol (280 and 254.7%) in normal and glaucomatous rabbits, were attained compared to the marketed eye drops, respectively. Hence, the developed pH-triggered nanoparticulate gelling system might provide a promising carrier for ophthalmic drug delivery and for improved augmentation of glaucoma.
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Glaucoma , Liposomas , Animales , Betaxolol , Portadores de Fármacos/uso terapéutico , Sistemas de Liberación de Medicamentos , Geles/uso terapéutico , Glaucoma/tratamiento farmacológico , Concentración de Iones de Hidrógeno , Tamaño de la Partícula , ConejosRESUMEN
Betaxolol is a relatively cardioselective ß-adrenoceptor blocking drug, with no partial agonist (intrinsic sympathomimetic) activity and weak membrane-stabilizing (local anesthetic) activity. Betaxolol selectively and competitively binds to and blocks beta-1 (ß1) adrenergic receptors in the heart, thereby decreasing cardiac contractility and rate. This leads to a reduction in cardiac output and lowers blood pressure. When applied topically in the eye, this agent reduces aqueous humor secretion and lowers the intraocular pressure (IOP). In addition, betaxolol prevents the release of renin, a hormone secreted by the kidneys that causes constriction of blood vessels. Betaxolol (S)-(-)-enantiomer shows higher pharmacological activity. This chapter provides a complete review of nomenclature, physiochemical properties, methods of preparation, identification techniques and various qualitative and quantitative analytical techniques as well as pharmacology of betaxolol. In addition, the chapter also includes review of several methods for enantiomeric separation betaxolol using chromatographic techniques.
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Antagonistas Adrenérgicos beta , Betaxolol , Oftalmopatías/tratamiento farmacológico , Antagonistas Adrenérgicos beta/farmacología , Betaxolol/farmacología , Presión Sanguínea/efectos de los fármacos , Corazón/efectos de los fármacos , Humanos , Presión Intraocular/efectos de los fármacos , Riñón/efectos de los fármacos , Renina/metabolismoRESUMEN
Introduction: DEND syndrome is a rare channelopathy characterized by a combination of developmental delay, epilepsy and severe neonatal diabetes. Gain of function mutations in the KCNJ11 gene, encoding the KIR6.2 subunit of the IKATP potassium channel, stand at the basis of most forms of DEND syndrome. In a previous search for existing drugs with the potential of targeting Cantú Syndrome, also resulting from increased IKATP, we found a set of candidate drugs that may also possess the potential to target DEND syndrome. In the current work, we combined Molecular Modelling including Molecular Dynamics simulations, with single cell patch clamp electrophysiology, in order to test the effect of selected drug candidates on the KIR6.2 WT and DEND mutant channels. Methods: Molecular dynamics simulations were performed to investigate potential drug binding sites. To conduct in vitro studies, KIR6.2 Q52R and L164P mutants were constructed. Inside/out patch clamp electrophysiology on transiently transfected HEK293T cells was performed for establishing drug-channel inhibition relationships. Results: Molecular Dynamics simulations provided insight in potential channel interaction and shed light on possible mechanisms of action of the tested drug candidates. Effective IKIR6.2/SUR2a inhibition was obtained with the pore-blocker betaxolol (IC50 values 27-37 µM). Levobetaxolol effectively inhibited WT and L164P (IC50 values 22 µM) and Q52R (IC50 55 µM) channels. Of the SUR binding prostaglandin series, travoprost was found to be the best blocker of WT and L164P channels (IC50 2-3 µM), while Q52R inhibition was 15-20% at 10 µM. Conclusion: Our combination of MD and inside-out electrophysiology provides the rationale for drug mediated IKATP inhibition, and will be the basis for 1) screening of additional existing drugs for repurposing to address DEND syndrome, and 2) rationalized medicinal chemistry to improve IKATP inhibitor efficacy and specificity.
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Contact lenses are ideal medical devices to sustain the release of ophthalmic drugs. However, the incorporation of drug loaded system can cause visual obstruction and poor oxygen/light permeability which restrict the application of contact lens for long-term wearing. Inspired by the physiological structure of our human eyes, we assume a circular-ring type inner layer embedded CLs might be a good solution to address the above-mentioned problems. In this study, taking betaxolol hydrochloride (BH) as a model drug, its complex with ion exchange resin was used as a carrier for adjusting drug loading amount, which is being dispersed into circular-ring shape Eudragit® S100 film as an inner layer, silicone-based hydrogel as the outer layer. Influence of resin particle size and drug/S100 ratio on drug release profiles was investigated. It was demonstrated that using resin as a carrier can not only increase drug loading amount but also sustain drug release, with the drug release rate well-tuned by either changing particle size of the resin or S100 ratio. Meanwhile S100 can well function as a pH-triggered drug release matrix, with limited drug leakage in the storage medium. Light transmittance of over 97% was achieved in the novel circular-ring layer-embedded CLs. Oxygen permeability coefficient (Dk) of the circular-ring film embedded CLs was 31.1 ± 3.7 barrer, similar to that of pure CLs. The sustained drug release behavior of this circular-ring embedded CLs was also well demonstrated in vivo. A level A IVIVC between in vitro drug release and in vivo drug concentration in tear fluid of the circular-ring embedded CLs was established. In conclusion, this circular-ring embedded contact lens is very promising for ophthalmic drug delivery with enhanced compatibility, sustained and pH triggered drug release characteristics.
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Betaxolol/administración & dosificación , Lentes de Contacto , Portadores de Fármacos , Ácidos Polimetacrílicos/química , Siliconas/química , Administración Oftálmica , Animales , Betaxolol/química , Betaxolol/farmacocinética , Preparaciones de Acción Retardada , Composición de Medicamentos , Liberación de Fármacos , Concentración de Iones de Hidrógeno , Masculino , Tamaño de la Partícula , Conejos , Lágrimas/metabolismoRESUMEN
PURPOSE: The purpose of the study was to evaluate influence of betaxolol, brimonidine and carteolol in the progression of the visual field defects during time at patients with normotensive glaucoma (NTG). MATERIALS AND METHODS: This study included (60 eyes of) 30 patients with NTG. First group consisted of 20 eyes of 10 patients of the average age of 58.5 years, who were treated by betaxolol. Second group also consisted of 20 eyes of 10 patients of the average age of 62.6 years and they were treated by brimonidine. Third group had the same count of the eyes and patients, the average age was 61.1 years and these patients were treated by carteolol. Diagnose of NTG was based on the comprehensive ophthalmological examination including electroretinography and visual evoked potentials. Visual fields were examined by fast threshold glaucoma test using Medmont M700 device. We compared pattern defect (PD) in the visual field for 3 years. The including criteria were: similar visual field findings at the beginning of the study, stable eye therapy (treatment was not changed during the study), uncorrected or best corrected (up to +-3 D) visual acuity of 1,0 of ETDRS, intraocular pressure between 10-15 mm Hg, if present, then compensated cardiovascular disease, no other internal or neurological disorders. RESULTS: We didnt notice any statistically important difference of PD. The study revealed that brimonidin (p=0,99) and betaxolol (p = 0,81) had the best effect. CONCLUSION: Local therapy of betaxolol, brimonidine and carteolol has an essential clinical value in normotensive glaucoma. All the mentioned treatments had a protective effect on the visual field. However, local side-effects of brimonidinu are a question.
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Carteolol , Glaucoma de Ángulo Abierto , Glaucoma , Betaxolol , Potenciales Evocados Visuales , Humanos , Presión Intraocular , Persona de Mediana EdadRESUMEN
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.
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Betaxolol , Timolol , Administración Tópica , Antagonistas Adrenérgicos beta , Animales , Atenolol , Disponibilidad Biológica , Cromatografía Liquida , Soluciones Oftálmicas , Conejos , Espectrometría de Masas en TándemRESUMEN
PURPOSE: The aim of this study was to evaluate the effects of 0.0015% preservative-free (PF) tafluprost alone and in combination with 0.5% timolol maleate or 0.5% betaxolol HCl on Schirmer tear test (STT), intraocular pressure (IOP), and pupil diameter (PD) in clinically normal dogs. METHODS: Twenty-one healthy adult castrated male cross-bred dogs were used in this study. Dogs were randomly divided into three groups. The first group received one drop of (PF) tafluprost (Taf), in a randomly selected eye. The second group received one drop of (PF) tafluprost plus one drop of timolol maleate (Taf-Tim), and the last group received one drop of (PF) tafluprost plus one drop of betaxolol HCl, (Taf-Bet). In all groups, the fellow eyes were served as control and received one drop of saline as a placebo. IOP, STT, and PD measurements were performed at the baseline and every 30 min for the first 2 h, every 2 h for the next 10 h, and at 24 h and 36 h post-instillation (PI). RESULTS: In all groups, significant differences in IOP values were observed between treated and untreated eyes (Taf: p < 0.001, Taf-Tim: p = 0.014, Taf-Bet: p = 0.008). The maximum reduction in mean IOP after unilateral administration of Taf, Taf-Tim, and Taf-Bet was 8.3 mmHg, 10.7 mmHg, and 13 mmHg, respectively. No significant differences in STT values were observed between treated and untreated eyes at any time points. In all groups, significant differences in PD values were observed between treated and untreated eyes in all time points except the baseline and 36 h post-drug instillation (p < 0.001). CONCLUSIONS: Tafluprost alone or in combination with timolol and betaxolol was able to reduce intraocular pressure. The greatest effect of the drugs occurred 6 and 8 h PI. The present study revealed that the combination of tafluprost/betaxolol is more potent in decreasing IOP than tafluprost alone or a combination of tafluprost/timolol in healthy dogs.
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Presión Intraocular , Timolol , Animales , Perros , Masculino , Administración Tópica , Antihipertensivos/farmacología , Antihipertensivos/uso terapéutico , Betaxolol/farmacología , Prostaglandinas F , Pupila , Timolol/farmacologíaRESUMEN
Montmorillonite-loaded solid lipid nanoparticles with good biocompatibility, using Betaxolol hydrochloride as model drug, were prepared by the melt-emulsion sonication and low temperature-solidification methods and drug bioavailability was significantly improved in this paper for the first time to application to the eye. The appropriate physical characteristics were showed, such as the mean particle size, Zeta potential, osmotic pressure, pH values, entrapping efficiency (EE%) and drug content (DC%), all showed well suited for possible ocular application. In vitro release experiment indicated that this novel system could continuously release 57.83% drugs within 12 h owing to the dual drug controlled-release effect that was achieved by ion-exchange feature of montmorillonite and structure of solid lipid nanoparticles. Low irritability and good compatibility of nanoparticles were proved by both CAM-TBS test and cytotoxicity experiment. We first discovered from the results of Rose Bengal experiment that the hydrophilicity of the drug-loaded nanoparticles surface was increased during the loading and releasing of the hydrophilic drug, which could contribute to prolong the ocular surface retention time of drug in the biological interface membrane of tear-film/cornea. The results of in vivo pharmacokinetic and pharmacodynamics studies further confirmed that increased hydrophilicity of nanoparticles surface help to improve the bioavailability of the drug and reduce intraocular pressure during administration. The results suggested this novel drug delivery system could be potentially used as an in situ drug controlled-release system for ophthalmic delivery to enhance the bioavailability and efficacy.
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Bentonita/química , Betaxolol/administración & dosificación , Materiales Biocompatibles/química , Córnea/efectos de los fármacos , Portadores de Fármacos/química , Glaucoma/tratamiento farmacológico , Nanopartículas/química , Animales , Humor Acuoso/efectos de los fármacos , Humor Acuoso/metabolismo , Betaxolol/farmacocinética , Betaxolol/farmacología , Disponibilidad Biológica , Línea Celular , Supervivencia Celular/efectos de los fármacos , Córnea/patología , Modelos Animales de Enfermedad , Composición de Medicamentos , Liberación de Fármacos , Estabilidad de Medicamentos , Células Epiteliales/efectos de los fármacos , Células Epiteliales/patología , Glaucoma/metabolismo , Humanos , Presión Intraocular/efectos de los fármacos , Tamaño de la Partícula , Conejos , Propiedades de SuperficieRESUMEN
Conventional ophthalmic eye drops are limited by their rapid elimination rate and short time of action. Ion exchange resin has been used to achieve sustained ocular drug delivery but the high selectivity of drug molecules restricts its broad application. In situ gel system seems to be a good strategy to address these problems but the influence of in situ gel type on the sustained release behavior and tissue distribution after ocular application is unclear. Therefore, in this study, using betaxolol hydrochloride as a model drug, poloxamer 407 and methylcellulose as the carriers, two thermosensitive in situ gel systems were prepared and characterized. Influence of formulation composition type and concentration on in vitro drug release was studied. Tissue distribution after ocular delivery of two different thermosensitive in situ gels was studied and compared with commercial BH eye drop (Betoptic S®). In vitro studies demonstrated that addition of 4% HPMC 606W in 15% P407 solution and 5% PEG4000 in 2% MC solution obtained gels with appropriate gelation temperature and similar sustained drug release rate. In vivo tissue distribution study indicated that they presented similar drug concentration in cornea, iris-ciliary and aqueous humor irrespective of gel type, with higher drug concentration achieved after 4 h compared to the commercial resin suspension eye drops. The AUC and MRT of the two in situ gel eye drops were 2 times higher than that of the commercial resin suspension eye drops in cornea. In conclusion, the two thermosensitive in situ gels have prolonged drug release after ocular drug delivery compared with ion exchange resin eye drops, implying their potential applications in clinic with broad drug adoptability.
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Ojo/efectos de los fármacos , Ojo/metabolismo , Geles/administración & dosificación , Geles/metabolismo , Soluciones Oftálmicas/administración & dosificación , Soluciones Oftálmicas/metabolismo , Resinas de Plantas/administración & dosificación , Animales , Betaxolol/química , Disponibilidad Biológica , Preparaciones de Acción Retardada/administración & dosificación , Preparaciones de Acción Retardada/metabolismo , Portadores de Fármacos/química , Sistemas de Liberación de Medicamentos/métodos , Liberación de Fármacos/fisiología , Excipientes/química , Metilcelulosa/química , Poloxámero/química , Conejos , Temperatura , Distribución Tisular/fisiologíaRESUMEN
The mechanisms of drug clearance from the aqueous humor are poorly defined. In this study, a cocktail approach was used to simultaneously determine the pharmacokinetics of three ß-blocker agents after intracameral (ic) injection into the rabbit eyes. Aqueous humor samples were collected and analyzed using LC-MS/MS to determine drug concentrations. Pharmacokinetic parameters were obtained using a compartmental fitting approach, and the estimated clearance, volume of distribution, and half-life values were the following: atenolol (6.44 µL/min, 687 µL, and 73.87 min), timolol (19.30 µL/min, 937 µL, and 33.64 min), and betaxolol (32.20 µL/min, 1421 µL, and 30.58 min). Increased compound lipophilicity (atenolol < timolol < betaxolol) resulted in higher clearance and volume of distributions in the aqueous humor. Clearance of timolol and betaxolol is about 10 times higher than the aqueous humor outflow, demonstrating the importance of other elimination routes (e.g., uptake to iris and ciliary body and subsequent elimination via blood flow).
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Antagonistas de Receptores Adrenérgicos beta 1/farmacocinética , Atenolol/farmacocinética , Betaxolol/farmacocinética , Inyecciones Intraoculares/métodos , Timolol/farmacocinética , Animales , Humor Acuoso/química , Humor Acuoso/efectos de los fármacos , Humor Acuoso/metabolismo , Atenolol/administración & dosificación , Betaxolol/administración & dosificación , Cromatografía Liquida , Combinación de Medicamentos , Semivida , Presión Intraocular/efectos de los fármacos , Masculino , Tasa de Depuración Metabólica , Conejos , Espectrometría de Masas en Tándem , Timolol/administración & dosificación , Distribución TisularRESUMEN
Early detection and management of elevated blood pressure is crucial in reducing the burden of cardiovascular disease (CVD). The importance of an absolute risk assessment and patient risk stratification has been highlighted in the European hypertension guidelines since 2003. Amongst numerous risk factors influencing patient prognosis, elevated heart rate (HR) has been indicated as important predictor of future risk of hypertension, coronary heart disease, sudden cardiac death, heart failure, CVD, stroke, total cancer and mortality. Given that resting HR can be easily determined in clinical practice and modified by lifestyle changes as well as beta-blocker therapy, it seems reasonable that lowering resting HR should be a potential target to reduce disease burden and premature mortality. However, there is a lack of outcome studies of HR lowering in tachycardia-related hypertension. This review outlines the underlying mechanisms of early course hypertension pathophysiology with the critical role of the sympathetic nervous system activation, the prognostic significance of fast HR and the mechanistic rationale for the use of non-pharmacological approaches and/or highly long-acting cardioselective beta-blockers with some consideration given to betaxolol properties.