1. Investigación
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- Ex vivo rabbit cornea diffusion studies with a soluble insert of moxifloxacin
2018 The objective of this research was to develop and evaluate an ocular insert for the controlled drug delivery of moxifloxacin which could perhaps be used in the treatment of corneal keratitis or even bacterial endophthalmitis. We have evaluated the ex vivo ocular diffusion of moxifloxacin through rabbit cornea, both fresh and preserved under different conditions. Histological studies were also carried out. Subsequently, drug matrix inserts were prepared using bioadhesive polymers. The inserts were evaluated for their physicochemical parameters. Ophthalmic ex vivo permeation of moxifloxacin was carried out with the most promising insert. The formulate insert was thin and provided higher ocular diffusion than commercial formulations. Ocular diffusion studies revealed significant differences between fresh and frozen corneas. Histological examinations also showed differences in the thickness of stroma between fresh and frozen corneas. The ophthalmic insert we have developed allows a larger quantity of moxifloxacin to permeate through the cornea than existing commercial formulations of the drug. Ocular delivery of moxifloxacin with this insert could be a new approach for the treatment of eye diseases.
- Evaluation of percutaneous absorption of esculetin: effect of chemical enhancers
2013-01 Percutaneous transdermal absorption of esculetin (6,7-dihydroxycoumarin), an oxidative damage inhibitor, was evaluated by means of in vitro permeation studies in which vertical Franz-type diffusion cells and pig ear skin were employed. To determine the absorption of esculetin, we validated a simple, accurate, precise, and rapid HPLC-UV method. Additionally, the effects of several percutaneous enhancers were studied. Pretreatment of porcine skin was performed with ethanol (control vehicle), decenoic acid, oleic acid, R-(+)-limonene, and laurocapram (Azone®) (5% in ethanol, w/w, respectively). Pretreatment of skin with oleic acid or laurocapram led to statistically significant differences in the transdermal flux of esculetin with respect to controls. Of the two enhancers, laurocapram showed the greatest capacity to enhance the flux of esculetin across pig skin.
- HPLC-UV analytical validation of a method for quantification of progesterone in "ex vivo" trans-corneal and trans-scleral diffusion studies
2021-01-30 Progesterone (PG) diminishes free radical damage and thus can afford protection against oxidative stress affecting the retina. The therapeutic use of PG is limited because it is a highly hydrophobic steroid hormone with very low solubility in water. This is the main drawback for the therapeutic application of PG at ocular level. The aims of this study were: (i) to analyze if PG causes ocular irritation (ii) to validate a HPLC method to determine PG in ex vivo studies and (iii) to evaluate PG permeation through cornea and sclera. A high performance liquid chromatographic method was developed and validated to detect PG incorporated to β-cyclodextrin using a Waters Sunfire C18 (150 × 4.6 mm) reverse-phase column packed with 5 μm silica particles using a mobile phase consisted of a mixture of acetonitrile (ACN) and pure water 80:20 (v/v), pH 7.4. The limit of detection and the limit of quantification for 50 μL injection of PG were found to be 0.42 and 1.26 μg/mL, respectively. The calibration curve showed excellent linearity over the concentration range (0.5 μg/mL to 100 μg/mL). As proof of concept, ex-vivo experiments to investigate PG permeation through cornea and sclera with vertical diffusion cells were carried out to quantify PG diffusion. Ex vivo experiments demonstrate its applicability to investigate permeation levels of PG from 6.57 ± 0.37 μg/cm2 at cornea and 8.13 ± 0.85 μg/cm2 sclera. In addition, at the end of diffusion studies the amount of PG retained in each tissue was also quantified, and it was 40.87 ± 9.84 μg/cm2 (mean ± SD; n = 6) in cornea and 56.11 ± 16.67 μg/cm2 (mean ± SD; n = 6) in sclera.
- Development, characterization, and "ex vivo" evaluation of an insert for the ocular administration of progesterone
2021-09-05 Progesterone (PG) affords neuroprotection in degenerative diseases associated to oxidative stress, such as cataracts, age-related macular degeneration, glaucoma, diabetic retinopathy and retinitis pigmentosa. The aim of this project was to develop ocular inserts for delivery of PG to the eye. Different inserts with PG in its composition were formulated and the insert with the best characteristics (59% polyvinyl alcohol, 39% polyvinylpyrrolidone K30 and 2% propylene glycol) was selected for ex vivo studies. Physical characteristics and drug release patterns of the insert were analysed. In vitro diffusion studies revealed a controlled diffusion of progesterone. Ex vivo experiments demonstrated similar trans-corneal and trans-scleral PG diffusion (corneal apparent permeability coefficient 6.46 ± 0.38 × 10-7 cm/s and scleral apparent permeability coefficient 5.87 ± 1.18 × 10- 7 cm/s; mean ± SD; n = 5). However, the amount of PG accumulated in scleras was statistically higher than in corneas (30.07 ± 9.09 μg/cm2 and 15.56 ± 4.36 μg/cm2 respectively). The PG-loaded inserts (55.6 μg/cm2) were thin, translucent, showed no irritancy (HET-CAM test) and were elastic and robust, all suitable properties for its potential use in the treatment of several ocular diseases.
- Micelles of progesterone for topical eye administration : interspecies and intertissues differences in ex vivo ocular permeability
2020-07-26 Progesterone (PG) may provide protection to the retina during retinitis pigmentosa, but its topical ocular supply is hampered by PG poor aqueous solubility and low ocular bioavailability. The development of e cient topical ocular forms must face up to two relevant challenges: Protective barriers of the eyes and lack of validated ex vivo tests to predict drug permeability. The aims of this study were: (i) To design micelles using Pluronic F68 and Soluplus copolymers to overcome PG solubility and permeability; and (ii) to compare drug di usion through the cornea and sclera of three animal species (rabbit, porcine, and bovine) to investigate interspecies di erences. Micelles of Pluronic F68 (3–4 nm) and Soluplus (52–59 nm) increased PG solubility by one and two orders of magnitude, respectively and exhibited nearly a 100% encapsulation e ciency. Soluplus systems showed in situ gelling capability in contrast to the low viscosity Pluronic F68 micelles. The formulations successfully passed the hen’s egg-chorioallantoic membrane test (HET-CAM) test. PG penetration through rabbit cornea and sclera was faster than through porcine or bovine cornea, although the di erences were also formulation-dependent. Porcine tissues showed intermediate permeability between rabbit and bovine. Soluplus micelles allowed greater PG accumulation in cornea and sclera whereas Pluronic F68 promoted a faster penetration of lower PG doses.
- Evaluación de los conocimientos y habilidades de los alumnos del grado de Farmacia : Prueba ECOE (Evaluación Clínica Objetiva Estructurada)
2020-03-06 La enseñanza universitaria evoluciona hacia la formación basada en problemas. La prueba ECOE (Evaluación Clínica Objetiva Estructurada) permite evaluar la capacidad del alumno en tres de los cuatro escalones de la pirámide de Miller; saber, saber cómo y demostrar cómo (conocimientos, habilidades y actitudes). Esta es la prueba de evaluación de las practicas tuteladas y en la Universidad Cardenal Herrera CEU se ha impartido en los dos últimos cursos a un total de 79 alumnos con resultados satisfactorios. El alumno debe pasar por 5 estaciones donde en 5 minutos en cada una debe resolver el problema práctico que se le plantea. Un profesor entrenado hace de paciente y otro profesor evalúa las habilidades del alumno. Luego se pasó una encuesta de satisfacción anónima a los alumnos siendo el resultado de 4,12/6. Es necesario ir modificando los problemas planteados a los alumnos para que cada vez más se adapten a la realidad que se encontraran al obtener el grado como profesionales farmacéuticos. / Higher education evolves towards Problem Based Learning. The Objective Structured Clinical Examination (OSCE) assesses students’ competencies in three of the four levels of Miller’s pyramid; Knows, Knows How, and Shows How (knowledge, competence, and performance). In the last two years, a total of 79 students at Cardenal Herrera University CEU were assessed with this examination, with good results. Student are asked to go through 5 stations, in which they have 5 minutes to resolve a practical problem. A trained teacher acts as the patient, while another evaluates the student’s abilities. Next, an anonymous satisfaction survey is given to the students, with the result 4,12/6. The problems presented to the students must be changed constantly so that each time they increasingly adapt to the situations they will find in their real-life practice once the graduate as professional pharmacists.
- Ex-vivo trans-corneal and trans-scleral diffusion studies with ocular formulations of glutathione as an antioxidant treatment for ocular diseases
2020-09-10 Exposure to sunlight and contact with atmospheric oxygen makes the eye particularly susceptible to oxidative stress, which can potentially produce cellular damage. In physiological conditions, there are several antioxidant defense mechanisms within the eye. Glutathione (GSH) is the most important antioxidant in the eye; GSH deficit has been linked to several ocular pathologies. The aim of this study was to explore the potential for newly developed formulations allowing controlled delivery of antioxidants such as GSH and vitamin C (Vit C) directly to the eye. We have investigated the stability of antioxidants in aqueous solution and assessed ex-vivo the di usion of GSH through two ocular membranes, namely cornea and sclera, either in solution or included in a semisolid insert. We have also carried out the hen’s egg-chlorioallantoic membrane test (HET-CAM) to evaluate the ocular irritancy of the di erent antioxidant solutions. Our results showed that GSH is stable for up to 30 days at 4 C in darkness and it is not an irritant to the eye. The di usion studies revealed that the manufactured formulation, a semisolid insert containing GSH, could deliver this tripeptide directly to the eye in a sustained manner.
- Influence of chemical enhancers and iontophoresis on the in vitro transdermal permeation of Propranolol : evaluation by dermatopharmacokinetics
2018-12-07 The aims of this study were to assess, in vitro, the possibility of administering propranolol transdermally and to evaluate the usefulness of the dermatopharmacokinetic (DPK) method in assessing the transport of drugs through stratum corneum, using propranolol as a model compound. Four chemical enhancers (decenoic and oleic acid, laurocapram, and R-(+)-limonene) and iontophoresis at two current densities, 0.25 and 0.5 mA/cm2 were tested. R-(+)-limonene, and iontophoresis at 0.5 mA/cm2 were proven to be the most efficient in increasing propranolol transdermal flux, both doubled the original propranolol transdermal flux. Iontophoresis was demonstrated to be superior than the chemical enhancer because it allowed faster delivery of the drug. The DPK method was sufficiently sensitive to detect subtle vehicle-induced effects on the skin permeation of propranolol. The shorter duration of these experiments and their ability to provide mechanistic information about partition between vehicle and skin and diffusivity through skin place them as practical and potentially insightful approach to quantify and, ultimately, optimize topical bioavailability.
- Anti-angiogenic drug loaded liposomes : nanotherapy for early atherosclerotic lesions in mice
2018-01-01 Fumagillin-loaded liposomes were injected into ApoE-KO mice. The animals were divided into several groups to test the efficacy of this anti-angiogenic drug for early treatment of atherosclerotic lesions. Statistical analysis of the lesions revealed a decrease in the lesion size after 5 weeks of treatment.