New concepts regarding micro/nanopharmaceutical polymer systems with applications in ophthalmology and neurosciences

Particulate systems like micro/nanoparticles have been used as a physical approach to modify the pharmacokinetic and pharmacodynamic properties of various types of drug molecules increasing this way the drug bioavailability and avoiding the toxic level. The major advantages of the particulate systems include the protection of the drug entity in the systemic circulation, restriction access of the drug to the chosen sites and delivery of the drug at a controlled and sustained rate to the site of action. Various materials have been used in the formulation of micro/nanoparticles for drug delivery research to increase therapeutic benefit, while minimizing side effects. Each class of materials (metals, lipids, polymers) presents advantages which make them suitable for different classes of applications. This paper focuses mainly on polymer particulate systems due to their large applicability area given by the diversity of the polymers properties. We review various aspects of micro/nanoparticle formulation including preparation, release mechanisms, effect of their characteristics and their applications in the field of ophthalmology and neurosciences. Some of the most interesting applications of polymer micro/nanoparticulates in glaucoma, retinal disorders and optical nerve disorders, respectivelly in neurology and neurosurgery are presented

Loading of beclomethasone in liposomes and hyalurosomes improved with mucin as effective approach to counteract the oxidative stress generated by cigarette smoke extract

In this work beclomethasone dipropionate was loaded into liposomes and hyalurosomes modified with mucin to improve the ability of the payload to counteract the oxidative stress and involved damages caused by cigarette smoke in the airway. The vesicles were prepared by dispersing all components in the appropriate vehicle and sonicating them, thus avoiding the use of organic solvents. Unilamellar and bilamellar vesicles small in size (~117 nm), homogeneously dispersed (polydispersity index lower than 0.22) and negatively charged (~−11 mV), were obtained. Moreover, these vesicle dispersions were stable for five months at room temperature (~25◦C). In vitro studies performed using the Next Generation Impactor confirmed the suitability of the formulations to be nebulized as they were capable of reaching the last stages of the impactor that mimic the deeper airways, thus improving the deposition of beclomethasone in the target site. Further, biocompatibility studies performed by using 16HBE bronchial epithelial cells confirmed the high biocompatibility and safety of all the vesicles. Among the tested formulations, only mucin-hyalurosomes were capable of effectively counteracting the production of reactive oxygen species (ROS) induced by cigarette smoke extract, suggesting that this formulation may represent a promising tool to reduce the damaging effects of cigarette smoke in the lung tissues, thus reducing the pathogenesis of cigarette smoke-associated diseases such as chronic obstructive pulmonary disease, emphysema, and cancer

Formulation and evaluation of cefuroxim loaded submicron particles for ophthalmic delivery

cited By 8International audienceChitosan gelatin particles could be the ideal candidate for intraocular drug delivery due to their desirable properties. Double crosslinking in double emulsion has been used as an original and reliable method for particles preparation and their morphology has been optimized considering the main synthesis parameters such as polymers ratio, crosslinker amount, stirring speed, tensioactive amount and ionic crosslinking time, respectively. The particles have been analyzed for their physical-chemical properties (swelling degree, drug loading and release capacity, surface characteristics, etc.), the enzymatic degradation properties along with in vivo ocular investigations (ocular biodistribution, in vivo drug release). In the present study cefuroxim was used as a model drug, which is generally used in the prophylaxis of postoperative endophthalmitis following cataract surgery after intraocular administration. The present study proved that the dimensions and the physical-chemical properties of the particles can be modulated (by varying the preparation parameters) to facilitate the administration, the biodistribution and the drug release in the specific segment of the eye. This experimental study demonstrated also the ability of fluorescent nanoparticles to penetrate ocular tissues close to the administration site (intravitreal injection) and especially their tendency to migrate deep in the retina at time intervals of 72 h. © 2015 Published by Elsevier B.V

Polyglobalide-Based Porous Networks Containing Poly(ethylene glycol) Structures Prepared by Photoinitiated Thiol-Ene Coupling

The high interest in polymers from natural resources prompted us to investigate the use of enzymatically synthesized polyglobalide (PGL) in the preparation of polymer networks with potential applications as biomaterials for drug delivery devices. Polymer networks were obtained under mild conditions by photoinitiated thiol-ene coupling between PGL and a poly(ethylene glycol-co-thiomalate) (PEG-SH) copolymer obtained by polycondensation. The obtained polymer networks were thoroughly characterized by Raman spectroscopy, scanning electron microscopy, titration of thiol groups and elemental analysis. Our study took into consideration the synthesis parameters for the polymer networks, such as the total polymer concentration and the SH/C=C functionality molar ratio. Swelling in both THF and water was assessed, and the potential of the materials for drug delivery was determined. The scanning electron microscopy images showed that the prepared polymer networks may have different morphologies ranging from homogeneous polymer materials to macroporous structures. Additionally, the prepared materials were found to be suitable from a cytotoxicity point of view, enabling their application as biomaterials for drug delivery devices. © 2018 American Chemical Society.SASPRO Programme of the Slovak Academy of Sciences [1628/03/02]; People Programme (Marie Curie Actions) European Union's Seventh Framework Programme under REA Grant [609427]; National Scholarship Programme of the Slovak Republic [18428]; Ministry of Education, Youth and Sports of the Czech Republic through program NPU I [LO1504]; [APVV-15-0545]; [VEGA 2/0158/17]; [VEGA 2/0124/18

Drug Release Kinetics from Polymer Matrix through Fractal Approximation of Motion

The present paper analyzes the process of drug release from polymer matrix. This process has been considered as fractal polymer process. Since complexity of physical processes is replaced by fractality, the paper studies the process through fractal approach. In drug dynamics, fractal “diffusion” equation can be obtained through fractal approximation of motion. All experimental release curves have been best demonstrated by Weibull relation (which was, in its turn, also demonstrated). Weibull parameters are related to the fractal dimension of drug release kinetics from a polymer matrix. Such a dimension can characterize and measure the complexity of the system. In the above-mentioned context, some experimental results of our researchers are presented and analyzed by comparing them with Peppas relation, a basic law in the description of drug release kinetics. Consequently, experimental data for Weibull relation are better correlated with certain resulting factors. At the same time, some conclusions regarding the phenomena involved in the process are considered as being based on the approach

Double Cross-linked Chitosan—Gelatin Particulate Systems for Ophthalmic Applications

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Development of a Prolonged-Release Drug Delivery System with Magnolol Loaded in Amino-Functionalized Mesoporous Silica

Magnolol (MG) is a small-molecule neolignan polyphenolic compound isolated from the genus Magnolia. The anti-inflammatory, anti-oxidative, anti-diabetic, anti-tumorgenic, anti-neurodegenerative, anti-depressant and anti-microbial properties of MG are well documented in recent literature. These fascinating multiple biological activities of MG encourage research about the development of new delivery and administration approaches able to maximize its potential benefits. This study describes the amino-functionalization of the SBA-15 (Santa Barbara Amorphous) mesoporous matrix by post-synthesis grafting using APTES (3-aminopropyltriethoxysilane) and the characterization of amino-functionalized mesoporous silica SBA-15 loaded with MG in order to achieve modified drug delivery systems. The amino-functionalization of silica SBA-15 was carried out by grafting by refluxing in dry toluene. The powders obtained were characterized texturally by Brunauer-Emmett-Teller (BET) surface area analysis measurements and morphologically by scanning electron microscopy. MG loading degree in the nanoporous matrix was determined by the HPLC method at λ = 290 nm. Results showed that by grafting the amino groups in the silica SBA-15, we obtained amino-functionalized silica SBA-15 with an ordered structure, with specific surfaces and pore sizes that differ from the original matrix, which was reflected in the amount of MG immobilized and release kinetics profile