The use of chitosan as a pharmaceutical excipient in the ocular field is already established. Nevertheless, some aspects related to its ocular administration, such as sterilization and excipient's pharmacokinetics, remain unclear. So, in this study, we evaluated those two relevant aspects, related to chitosan administration in eye. We used chitosan-based ocular inserts (CI) as formulation model. CI were produced by solvent/casting method and sterilized by saturated steam. Sterilization was confirmed by direct inoculation of inserts in suitable microbiological growth media. Physicochemical characterization of inserts before and after sterilization was performed.Results suggested that, although steam sterilization changed the arrangement of the matrix, the heat and the humidity did not modify the structure of the main polymeric chain. Pharmacokinetics of CI radiolabeled with technetium-99m ( 99m Tc) was assessed by scintigraphic images and ex vivo biodistribution study, after ocular administration in male Wistar rats. Scintigraphic and images analysis and ex vivo biodistribution study showed that the insert remained mainly in the eye until 6 hr after administration and its degradation products began to migrate to the abdominal cavity after 18 hr. Together, these data represent an important step forward the manufacturing and the clinical application of CI in the ophthalmic field. K E Y W O R D S chitosan, excipient, ocular drug delivery, pharmacokinetics, sterilization
A benzamidine derivative from diminazene was tested for a novel activity: treatment of primary open‐angle glaucoma. This drug was incorporated into mucoadhesive polymeric inserts prepared using chitosan (Chs) and chondroitin sulfate (CS). Of current interest is the mucoadhesion, which increases the contact time with the ocular surface, resulting in improved bioavailability; also, the inserts are made to act as a prolonged release system. In the present work the inserts were prepared by the solvent casting method using different polymeric proportions (30:70, 50:50, 75:25% w/w Chs:CS and 100% Chs). Thermal analysis and infrared spectroscopy both demonstrated physical dispersion of the active drug. The most promising was the 50:50% Chs:CS which demonstrated that it was not fragile and has an in vitro release profile of up to 180 minutes. In addition, it presented greater adhesion strength in relation to the other formulations. These physicochemical results corroborate the in vivo tests performed. In this sense, we also demonstrated that the treatment with the 50:50% insert can control the intraocular pressure (IOP) for at least 3 weeks and prevents damage to the retinal ganglion cells (RGCs) compared to the placebo insert. Thus, this indicates thus that the new drug is quite viable and promising in glaucoma treatment.
Even when treated adequately, pulmonary tuberculosis can lead to pulmonary sequelae. Patients treated for PTB between 2012 and 2016 answered a standardized questionnaire and underwent chest radiography and spirometry, measurement of absolute pulmonary volume, Diffusing Capacity for Carbon Monoxide (DLCO) and the 6-min walk test (6MWT) on two occasions: within the first year after the end of treatment (follow-up 1), and one and two years after follow-up 1 (follow-up 2). A total of 55 patients they underwent spirometry, 23 (41.82%) had obstructive ventilatory disorder (OVD) and eight (14.5%) had moderate OVD. In total, 29 patients underwent pulmonary function tests (PFTs) and 24 patients underwent the 6MWT on two occasions. The functional changes after PTB treatment appear not to have varied between one and two years of follow-up. There was a correlation between low FEV 1 and low DLCO (p<0.001); low DLCO and low 6MWT (p<0.001) and radiographic abnormalities and low FEV 1 (p=0.033). The most frequently observed change in spirometry was found in patients with OVD.
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