Use of 2% hydroxypropyl methylcellulose to prevent the corneal swelling during the in vitro mechanical characterization

The aim of this study was to assess the use of 2% HPMC during in vitro uniaxial tensile tests, with corneal strips immediately obtained or after storing the eyes for 24¿h in 0.9% NaCl solution at 4¿¿. The purpose was to establish a standardized procedure to prevent phenomena which can modify the mechanical properties of the tissue. Rabbit eyes were divided into four groups. Group A had seven eyes that were preserved in NaCl solution for 24¿h before testing. Group B had seven eyes that were immediately tested. In both groups, to prevent both swelling and dehydration, 2% hydroxypropyl methylcellulose (2% HPMC) was applied. Group C had seven eyes that were preserved in NaCl solution for 24¿h before testing. Group D had seven eyes that were immediately tested. In both groups, HPMC was not applied. Regarding the mechanical response, groups with HPMC showed similar Cauchy stress–stretch curves and there were no statistically significant differences at 5%, 10% and 15% strain between them, which mean that both showed similar mechanical behavior. The same result was obtained between groups without HPMC. However, for coupled groups with and without HPMC, statistically significant differences at 10% and 15% strain were observed. On the other hand, when grouped by storage time, statistically significant differences were found between groups that had eyes preserved for 24¿h with and without HPMC, respectively, as well as between groups immediately tested with and without HPMC, respectively, at 15% strain. Nevertheless, if coupled groups were considered, between groups that were preserved for 24¿h in NaCl before testing and groups that were immediately tested, no statistically significant differences were obtained. In addition, the Cauchy stress–stretch curves of groups without HPMC showed a decreasing slope of the linear part (strain¿>¿8%) of the graph during the experiment. In summary, the use of HPMC during the handling of the tissue from excision to testing seems to prevent both swelling and dehydration

Assessment of corneal biomechanical properties and intraocular pressure in myopic Spanish healthy population

Purpose. To examine biomechanical parameters of the cornea in myopic eyes and their relationship with the degree of myopia in a western healthy population. Methods. Corneal hysteresis (CH), corneal resistance factor (CRF), Goldmann correlated intraocular pressure (IOP), and corneal compensated IOP (IOPcc) were measured using the ocular response analyzer (ORA) in 312 eyes of 177 Spanish subjects aged between 20 and 56 years. Refraction was expressed as spherical equivalent (SE), which ranged from 0 to -16.50 diopters (D) (mean: -3.88 ± 2.90 D). Subjects were divided into four groups according to their refractive status: group 1 or control group: emmetropia (-0.50 = SE 0.05); nevertheless, IOPcc was significantly higher in the moderatelymyopic (15.47±2.47mmHg) and highlymyopic (16.14± 2.59mmHg) groups than in the emmetropia (15.15 ± 2.06mmHg) and low myopia groups (14.53 ± 2.37mmHg). No correlation between age and the measured parameters was found. CH and IOPcc were weakly but significantly correlated with SE (¿ = 0.171, ¿ = 0.002 and ¿ = -0.131, ¿ = 0.021, resp.). Conclusions. Present study showed only a very weak, but significant, correlation between CHand refractive error, with CH being lower in both moderately and highlymyopic eyes than that in the emmetropic and low myopic eyes.These changes in biomechanical properties of the cornea may have an impact on IOP measurement, increasing the risk of glaucom

Los roedores del yacimiento musteriense de la Cueva de Gabasa (Pirineo Aragonés), Interés paleoecológico

The rodents of the Mousterian site Cueva de Gabasa (province of Huesca) have been studied in this report. The stratigraphical distribution of rodents has a paleoecological meaning in the karstic sit

Microemulsion-Based Vaginal Gel of Clotrimazole: Formulation, In Vitro Evaluation, and Stability Studies

The objective of the present investigation was to develop and evaluate microemulsion-based gel for the vaginal delivery of clotrimazole (CMZ). The solubility of CMZ in oils and surfactants was evaluated to identify components of the microemulsion. The ternary diagram was plotted to identify the area of microemulsion existence. Various gelling agents were evaluated for their potential to gel the CMZ microemulsion without affecting its structure. The bioadhesive potential and antifungal activity of the CMZ microemulsion-based gel (CMZ-MBG) was determined in comparison to the marketed clotrimazole gel (Candid-V® gel) by in vitro methods. The chemical stability of CMZ in CMZ-MBG was determined as per the International Conference on Harmonization guidelines. The CMZ microemulsion exhibited globule size of 48.4 nm and polydispersity index of 0.75. Carbopol® ETD 2020 could successfully gel the CMZ microemulsion without disturbing the structure. The CMZ-MBG showed significantly higher (P < 0.05) in vitro bioadhesion and antifungal activity as compared to that of Candid-V® gel. The stability studies indicated that CMZ undergoes acidic pH-catalyzed degradation at all the storage conditions at the end of 3 months