Heparin release from thermosensitive hydrogels

Thermosensitive hydrogels (TSH) were synthesized and investigated as heparin releasing polymers for the prevention of surface induced thrombosis. TSH were synthesized with N-isopropyl acrylamide (NiPAAm) copolymerized with butyl methacrylate (BMA) (hydrophobic) or acrylic acid (AAc) (hydrophilic) comonomers. The incorporation of hydrophobic and hydrophilic comonomers strongly influences the swelling/shrinking behavior of TSH. Upon deswelling, gels containing the hydrophobic comonomer formed a skin-type layer, which acted as a rate controlling membrane, while the hydrophilic comonomer greatly increased gel swelling, relative to NiPAAm. Equilibrium swelling in isotonic PBS and deswelling kinetics of the synthesized gels were examined at various temperatures. The loading of heparin into the different gels was studied as a function of temperature, solution concentration, and gel composition. The release kinetics of heparin was found to be influenced by gel composition and loading temperature; the release correlated with the gel deswelling kinetics. In the case of Ni-PAAm/BMA gel, the release profile of heparin was affected by temperature dependent properties of the skin-type diffusional barrier formed on the gel surface

ÚJ TIPUSÚ POLIMERGÉLEK KIFEJLESZTÉSE GYÓGYSZERÉSZETI ALKALMAZÁSOKRA = DEVELOPMENT OF NOVEL SMART POLYMER GELS FOR PHARMACEUTICAL APPLICATIONS

Poliszukcinimid- és poliaszparaginsav (PASP) alapú biokompatibilis géleket állítottunk elő és tanulmányoztuk ezek gélkollapszuson alapuló nyitó-záró mechanizmusát. A hálóláncok hidrofil/hidrofób jellegét különböző polaritású molekulák főlánchoz történő ojtásával módosítottuk, így multifunkcionális polimer géleket nyertünk.. A hálóláncok szerkezetét FTIR, NMR, SAXS, GPC és WAXS technikákkal vizsgáltuk. Tanulmányoztuk különböző méretű gélgömbök duzzadási kinetikáját a kooperatív diffúziós együttható meghatározása céljából. Vizsgáltuk metoprolol hatóanyag ((RS)-1-[4-(2-methoxyethyl)phenoxy]-3-propan-2-ylamino-propan-2-ol), valamint kalcium és aluminium ionok PASP gélekből való kioldódásának, valamit a duzzadásfok időfüggésére gyakorolt hatását. A munka jelentős része koreai és japán kutatási együttműködés keretében történt. | Chemically cross-linked biocompatible poly(aspartic acid) (PASP) gels were prepared by the hydrolysis of poly(succinimide) (PSI). We have modified the hydrophyl-hydrophobic character of network chains by grafting. FTIR, NMR, SAXS, GPC és WAXS techniques were used to characterize the structure of network chains as well as the degree of grafting. The PASP gels show a reversible volume phase transition as a function of pH and in the presence of calcium ions. Kinetics of hydrolysis induced swelling as well as pure swelling of PSI and PASP gels were studied. The release kinetics of metoprolol ((RS)-1-[4-(2-methoxyethyl)phenoxy]-3-propan-2-amino-propan-2-ol) drug as well as that of calcium and aluminum ions has been studied together with their influence on the swelling kinetics of spherical gels

SYNTHESIS AND STUDY OF THE SWELLING BEHAVIOR OF HYDROGELS BASED ON COPOLYMERS OF ACRILAMIDE WITH ACRYLIC AND METHACRYLIC

The hydrogels based on copolymer of acrylamide (AAm) and acrylic acid (AAc) were prepared through radical polymerization. The dependencies of the swelling ratio of gels from monomer ratio in the initial mixture were obtained. The kinetics of swelling of air-dried gels was studied and supposition put forward about the influence of the polymer gel structure to swelling processes

Reusable Ionogel-based Photo-actuators in a Lab-on-a-disc

This paper describes the design, fabrication and performance of a reusable ionogel-based photo-actuator, in-situ photopolymerised into a lab-on-a-disc microfluidic device, for flow control. The ionogel provides an effective barrier to liquids during storage of reagents and spinning of the disc. A simple LED (white light) triggers actuation of the ionogel for selective and precise channel opening at a desired location and time. The mechanism of actuation is reversible, and regeneration of the actuator is possible with an acid chloride solution. In order to achieve regeneration, the Lab-on-a-Disc device was designed with a microchannel connected perpendicularly to the bottom of the ionogel actuator (regeneration channel). This configuration allows the acid solution to reach the actuator, independently from the main channel, which initiates ionogel swelling and main channel closure, and thereby enables reusability of the whole device.Economía y Competitividad), Spain. This project has receivedfunding from the European Union Seventh Framework Programme(FP7) for Research, Technological Development and Demonstrationunder grant agreement no. 604241. JS and FBL acknowledge fund-ing support from Gobierno de Espa˜na, Ministerio de Economía yCompetitividad, with Grant No. BIO2016-80417-P and personallyacknowledge to Marian M. De Pancorbo for letting them to use herlaboratory facilities at UPV/EHU. A.T., L.F., and D.D. are grateful forfinancial support from the Marie Curie Innovative Training Net-work OrgBIO (Marie Curie ITN, GA607896) and Science FoundationIreland (SFI) under the Insight Centre for Data Analytics initiative,Grant Number SFI/12/RC/2289

Photocurable Bioink for the Inkjet 3D Pharming of Hydrophilic Drugs.

Novel strategies are required to manufacture customized oral solid dosage forms for personalized medicine applications. 3D Pharming, the direct printing of pharmaceutical tablets, is an attractive strategy, since it allows for the rapid production of solid dosage forms containing custom drug dosages. This study reports on the design and characterization of a biocompatible photocurable pharmaceutical polymer for inkjet 3D printing that is suitable for hydrophilic active pharmaceutical ingredients (API). Specifically, hyaluronic acid was functionalized with norbornene moieties that, in the presence of poly(ethylene) glycol dithiol, Eosin Y as a photoinitiator, and a visible light source, undergoes a rapid step-growth polymerization reaction through thiol-ene chemistry. The engineered bioink was loaded with Ropinirole HCL, dispensed through a piezoelectric nozzle onto a blank preform tablet, and polymerized. Drug release analysis of the tablet resulted in 60% release within 15 min of tablet dissolution. The study confirms the potential of inkjet printing for the rapid production of tablets through the deposition of a photocurable bioink designed for hydrophilic APIs

Chemically cross-linked poly(acrylic-co-vinylsulfonic) acid hydrogel for the delivery of isosorbide mononitrate.

We report synthesis, characterization, and drug release attributes of a series of novel pH-sensitive poly(acrylic-co-vinylsulfonic) acid hydrogels. These hydrogels were prepared by employing free radical polymerization using ethylene glycol dimethacrylate (EGDMA) and benzyl peroxide (BPO) as cross-linker and initiator, respectively. Effect of acrylic acid (AA), polyvinylsulfonic acid (PVSA), and EGDMA on prepared hydrogels was investigated. All formulations showed higher swelling at high pHs and vice versa. Formulations containing higher content of AA and EGDMA show reduced swelling, but one with higher content of PVSA showed increased swelling. Hydrogel network was characterized by determining structural parameters and loaded with isosorbide mononitrate. FTIR confirmed absence of drug polymer interaction while DSC and TGA demonstrated molecular dispersion of drug in a thermally stable polymeric network. All the hydrogel formulations exhibited a pH dependent release of isosorbide mononitrate which was found to be directly proportional to pH of the medium and PVSA content and inversely proportional to the AA contents. Drug release data were fitted to various kinetics models. Results indicated that release of isosorbide mononitrate from poly(AA-co-VSA) hydrogels was non-Fickian and that the mechanism was diffusion-controlled