S Pérez

Hospital Universitario Miguel Servet, Caesaraugusta, Aragon, Spain

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Publications (15)22.66 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Abstract Purpose: This study evaluated the vitreous pharmacokinetics and vitreous bioavailability of memantine following posterior-subtenon administration (PST) compared to intravitreal (INT) and intravenous routes (INV) in rabbits. Methods: Vitreous pharmacokinetic analysis was performed on female New Zealand (NZ) albino rabbits after PST, INT, and INV administration and calculating the pharmacokinetic parameters that describe memantine vitreous distribution. The vitreous bioavailability (F) and the relative vitreous bioavailability of memantine was estimated after posterior-subtenon administration (Frel (pst/int)) and after intravenous route (Frel (inv/int)) compared with intravitreal administration. Relative vitreous bioavailability of memantine was also estimated following PST administration compared with vitreous concentrations after intravenous administration (Frel (pst/inv)). Results: Memantine kinetics in the vitreous of NZ albino rabbits after PST administration can be explained by a one-compartment model, which was characterized by a fast absorption process, and a short terminal half-life. Vitreous pharmacokinetics following INV administration was also characterized by a fast absorption process, a terminal half-life significantly longer than the subtenon route, and low area under the curve values. High vitreous bioavailability after PST was observed, and the relative vitreous bioavailability of memantine following PST administration (0.53%) was greater than for intravenous administration (0.02%). Conclusions: Our results suggest that memantine reaches the vitreous after PST administration by local diffusion. These data also show that local diffusion of the drug is responsible for greater vitreous availability of memantine following PST administration compared with INV administration.
    Journal of ocular pharmacology and therapeutics: the official journal of the Association for Ocular Pharmacology and Therapeutics 03/2014; · 1.46 Impact Factor
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    ABSTRACT: Aim: To prepare and evaluate the in vitro release of memantine-loaded poly(anhydride) (Gantrez®) nanoparticles (NPs). The clinical safety and retinal toxicity caused by unloaded NPs after sub-Tenon and intravitreal ocular injections were also evaluated. Methods: Preparation and characterization of this type of NP as well as the in vitro release study are described. Twenty-three healthy New Zealand rabbits were used for clinical and histological assessment after sub-Tenon and intravitreal ocular injections of unloaded NPs. Results: The amount of drug associated with NPs was 55 µg of memantine/mg of NP. The release profile of memantine from this type of NPs was characterized by an initial burst effect, followed by continuous release of the drug for at least 15 days. No relevant complications were found during the clinical follow-up. The histological evaluation suggested that Gantrez NPs are well tolerated after sub-Tenon ocular injection and that signs of inflammation during the first days after intravitreal ocular injections can be considered a normal reaction of the eye's defence mechanism.
    Ophthalmic Research 04/2012; 48(3):109-17. · 1.56 Impact Factor
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    ABSTRACT: A new HPLC procedure with precolumn derivatization and rimantadine as the internal standard for determining memantine, a candidate agent for the treatment of glaucoma in plasma and vitreous humour, has been developed and validated. Precolumn derivatization was performed with 9-fluorenylmethyl-chloroformate-chloride (FMOC-Cl) as the derivatization reagent and followed by a liquid-liquid extraction with n-hexane. Optimal conditions for derivatization were an FMOC-Cl concentration of 1.5 mM, a reaction time of 20 min, the temperature at 30°C, the borate buffer pH 8.5, and a borate buffer-acetonitrile ratio of 1:1. The derivatives were analyzed by isocratic HPLC with the fluorescence detector λex 260 nm λem 315 nm on a Novapack C(18) reversed-phase column with a mobile phase of acetonitrile-water (73:27, v/v), 40°C, and a flow rate of 1.2 mL/min. The linear range was 10-1000 ng/mL with a quantification limit of ∼ 10 ng/mL for both types of samples. This analytical method may be suitable for using in ocular availability studies.
    Journal of chromatographic science 11/2011; 49(10):745-52. · 0.79 Impact Factor
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    ABSTRACT: PurposeTo study the ability of Heidelberg Retina Tomography III (HRT 3) measurements to predict perimetry changes in patients with early glaucoma or suspected primary open-angle glaucoma.
    Fuel and Energy Abstracts 04/2010; 85(4):138-143.
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    ABSTRACT: To study the ability of Heidelberg Retina Tomography III (HRT 3) measurements to predict perimetry changes in patients with early glaucoma or suspected primary open-angle glaucoma. One hundred and thirty two eyes with early glaucoma or suspected glaucoma with no changes in basal perimetry were prospectively selected and periodically evaluated over five years. The eyes were divided in two groups depending on the presence or absence of progression (changes in glaucoma perimetry). The association between morphometric parameters and baseline HRT 3 indices, glaucoma probability score (GPS) and Moorefield's Regression Analysis (MRA), and perimetry progression were studied using Cox multivariate regression analyses. Kaplan-Meier curves were used to illustrate the results. Forty-eight eyes (36.36%) showed perimetry progression. Perimetry progression showed higher correlations with the disc area (p = 0.001), the cup area (p = 0.002) and the vertical cup disc area (p = 0.001). Multivariate regression analyses showed that eyes with baseline MRA or baseline GPA changes were at a higher risk of having perimetry abnormalities and a faster progression. MRA and GPA indices are useful to predict perimetry progression in patients with early primary open-angle glaucoma or suspected glaucoma. These indices can be used as risk markers of functional progression in glaucoma.
    Archivos de la Sociedad Espanola de Oftalmologia 04/2010; 85(4):138-43.
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    ABSTRACT: To evaluate long-term intraocular pressure results after trabeculectomy in low risk patients. Therefore differences among glaucoma type and previous medical treatment will be evaluated. A retrospective follow-up study, ranging between 3 and 20 years, was carried out on 965 trabeculectomy surgeries without any surgical- failure factor. Follow-up was carried-out one day, one week, one month, three months, six months and annually after surgery until the last visit. Primary open angle (POAG) (671 eyes), pseudoexfoliative (PSXG) (156 eyes) and chronic closure angle glaucomas (CCAG) (138 eyes) were included. IOP under 21 Hg mm without medical treatment was considered absolute success, relative success included those eyes with pressures under 21 and one or two daily antiglaucomatous drops. Mean IOP ranged between 15 and 17 Hg mm. Mean IOP decreased from 30.7 to 37.4%. Relative success ten years after surgery was better in POAG; whereas absolute success resulted to be similar in POAG and PSXG. The group of patients less treated before surgery showed greater rate of absolute and relative success. Trabeculectomy alone is an efficient technique in long-term tensional control for uncomplicated eyes. The group of patients less treated before surgery and POAG showed greater rate success.
    Archivos de la Sociedad Espanola de Oftalmologia 08/2009; 84(7):345-51.
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    ABSTRACT: Objectives: To evaluate long-term intraocular pressure results after trabeculectomy in low risk patients. Therefore differences among glaucoma type and previous medical treatment will be evaluated. Methods: A retrospective follow-up study, ranging between 3 and 20 years, was carried out on 965 trabeculectomy surgeries without any surgical- failure factor. Follow-up was carried-out one day, one week, one month, three months, six months and annually after surgery until the last visit. Primary open angle (POAG) (671 eyes), pseudoexfoliative (PSXG) (156 eyes) and chronic closure angle glaucomas (CCAG) (138 eyes) were included. IOP under 21 Hg mm without medical treatment was considered absolute success, relative success included those eyes with pressures under 21 and one or two daily antiglaucomatous drops. Results: Mean IOP ranged between 15 and 17 Hg mm. Mean IOP decreased from 30.7 to 37.4%. Relative success ten years after surgery was better in POAG; whereas absolute success resulted to be similar in POAG and PSXG. The group of patients less treated before surgery showed greater rate of absolute and relative success. Conclusions: Trabeculectomy alone is an efficient technique in long-term tensional control for uncomplicated eyes. The group of patients less treated before surgery and POAG showed greater rate success (Arch Soc Esp Oftalmol 2009; 84: 345-352).
    Archivos de la Sociedad Espanola de Oftalmologia 07/2009; 84(7).
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    ABSTRACT: Ocular penetration of grepafloxacin into several ocular tissues was determined in albino and pigmented rabbits following a single intravitreal administration. After administration, grepafloxacin was detected in all ocular tissues studied in both breeds of rabbits. The superior mean penetration ratios were found in the chorioretina and lens of albino rabbits, and in the chorioretina, iris and lens of pigmented rabbits. A significantly greater penetration of grepafloxacin was found in the chorioretina and iris of the pigmented rabbits than in those of the albino rabbits. As a final conclusion, grepafloxacin detected in different ocular structures could attain therapeutic concentrations against a variety of ocular conditions.
    Chemotherapy 07/2004; 50(3):133-7. · 2.07 Impact Factor
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    ABSTRACT: This study evaluated the effect of doxorubicin on fibroblast migration and proliferation. An artificial wound was made in a fibroblast monolayer, and doxorubicin was added. The cell-free area was monitored. Viability and proliferation were assessed by the cell proliferation reagent WST-1. Doxorubicin at 10−6M or greater inhibited migration. Proliferation was decreased with 2.5×10−5 or more of doxorubicin. Doses at 5×10−5M and at 10−4M showed cellular toxicity. Doxorubicin effectively inhibits wound repair.
    Annals of Ophthalmology 05/2003; 35(1):48-52. · 0.16 Impact Factor
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    ABSTRACT: The efficacy of short-wavelength automated perimetry (SWAP) and conventional automated perimetry (CAP) in detecting the progression of glaucomatous visual field loss was compared. After 3 years, CAP detected progressive visual field damage in 3 (13.6%) of 22 eyes, while SWAP detected progressive visual field damage in 8 (36.6%) of 22 eyes. Thus, SWAP was more efficient than CAP in detecting progressive visual field losses in glaucomatous patients with incipient defects.
    Annals of Ophthalmology 11/2002; 34(4):194-197. · 0.16 Impact Factor
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    ABSTRACT: The pharmacokinetics of grepafloxacin were determined in albino and pigmented rabbits following a single 10 mg/kg intravenous administration. The penetration of grepafloxacin into various ocular tissues was also determined after continuous intravenous infusion in both types of animal. Grepafloxacin showed a bicompartmental model of distribution in both pigmented and albino rabbits with significant differences in the pharmacokinetics between the two types of animal. After continuous intravenous infusion, significantly greater penetration of grepafloxacin was found in the iris, cornea and chorioretina of pigmented rabbits compared with albino rabbits.
    Journal of Antimicrobial Chemotherapy 11/2002; 50(4):541-5. · 5.34 Impact Factor
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    ABSTRACT: To determine whether structural changes in the retinal nerve fiber layer (RNFL) and functional abnormalities in short-wavelength automated perimetry (SWAP) can predict the onset of functional losses in standard automated perimetry patients suspected of having glaucoma. Prospective observational case series. A total of 160 eyes of ocular hypertensive subjects (intraocular pressure greater than 21 mmHg and normal standard automated perimetry) were included in the study. The subjects underwent RNFL photographic evaluation and SWAP. Standard automated perimetries were repeated after 3 years to evaluate glaucomatous losses. Onset of glaucomatous defects in conventional automated perimetry after 3 years of follow-up, with or without prior glaucomatous defects in RNFL and SWAP. At the beginning of the study, 77 eyes showed RNFL losses (48%), and 58 eyes showed abnormalities in SWAP (36%). After the 3-year follow-up period, 14 of 77 eyes with RNFL losses had standard automated perimetry abnormalities (predicting sensitivity 93%), whereas 11 of 58 eyes with abnormal SWAP had standard automated perimetry losses (73% sensitivity). RNFL and SWAP losses are signs of early glaucomatous damage and can predict functional losses in standard automated perimetry.
    Ophthalmology 05/2002; 109(4):761-5. · 5.56 Impact Factor
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    ABSTRACT: PurposeTo determine whether structural changes in the retinal nerve fiber layer (RNFL) and functional abnormalities in short-wavelength automated perimetry (SWAP) can predict the onset of functional losses in standard automated perimetry patients suspected of having glaucoma.
    Ophthalmology 01/2002; 109(4):761-765. · 5.56 Impact Factor
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    ABSTRACT: To determine width and shape of neuro-retinal rim in normal hypertensive subjects and patients with glaucomatous damage. Patients underwent a perimetry and a photographic retinal nerve fiber evaluation. Patients were divided in three groups: normal subjects (n=34), ocular hypertension subjects (n=38) and glaucoma patients (n=34). Neuro-retinal rim was measured using 40 degrees stereoscopic photographs with center in the optic nerve head based on a biomorphometry technique. In normal subjects neuro-retinal rim appeared wider in the lower pole, followed by the upper, nasal and temporal aspects. Optic nerve fiber layer showed a decreased thickness in hypertensive and glaucoma patients, particularly in sectors of the temporal aspect of the optic nerve (p<0.05). A Planimetry study of the optic nerve is able to detect alterations in normal neuro-retinal rim configuration and can as well detect thinning of the rim, particularly in temporal, upper and lower areas.
    Archivos de la Sociedad Espanola de Oftalmologia 11/2001; 76(11):673-8.
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    ABSTRACT: To study the antiinflammatory effect of topical pranoprofen on the lipoxygenase metabolism of the arachidonic acid in albino rabbits. Endotoxin-induced uveitis (EIU) was produced in albino rabbits by intravitreal injection in the right eye with 10 microg of Salmonella typhymurium lipopolysacharide A in 5 microl saline solution. We have used 5 groups of 12 animals each. Control group (G-I) was injected with 5 microl of saline solution and 5 microl of ET solution were injected in the remaining groups. Groups III, IV and V were treated with topical pranoprofen 2 hours before intravitreal injection, immediately after and every 6, 4 and 2 hours respectively. The animals were sacrificed 24 hours after the ET administration. Cellular and B4 leukotrien concentration in the aqueous humour was determined. The groups treated with pranoprofen showed a significant decrease in the cellular concentration in relation to the group of endotoxin (G-II). We did not observe any difference in the B4 leukotriene concentration between ET group and topical pranoprofen groups. Topical pranoprofen has not increased the lipoxygenase metabolism of the arachidonic acid.
    Archivos de la Sociedad Espanola de Oftalmologia 07/2000; 75(6):377-82.

Publication Stats

50 Citations
22.66 Total Impact Points

Institutions

  • 2000–2009
    • Hospital Universitario Miguel Servet
      • Servicio de Neurología
      Caesaraugusta, Aragon, Spain
  • 2004
    • University of Zaragoza
      • Departamento de Farmacología y Fisiología
      Zaragoza, Aragon, Spain