Development and in vitro/in vivo evaluation of dihydroergotamine mesylate loaded maltodextrin-pullulan sublingual films

Dihydroergotamine mesylate (DHE), ergotamine derivative, has been offered for clinical use to stop or treat symptoms of an emerging migraine as injection for more than a half century. It is shown that bioavailability of DHE greatly changes between the subjects and up to 99% of the orally absorbed dose may be cleared by first pass metabolism. The aim of this study was to design and optimize DHE fast-dissolving sublingual films for migraine treatment. For this purpose pullulan and maltodextrin was chosen as film-forming polymers and propylene glycol as plasticizer. For optimization process Box Behnken design was used. The formed films were free from air bubbles, cuttings, or cracks. Disintegration, mechanical strength and dissolution of films were compared. It is found that pullulan and maltodextrin formed films with the most desired properties at the concentration of 1.5% and 2%. The application of optimum formulation to rabbits showed that bioavailability of formulation is about 23.35% with a t_max 20?min. Due to this fast onset of action and higher bioavailability than oral administration, it is suggested that the polymer combinations of pullulan and maltodextrin formed successful films and were considered as an alternative dosage form for DHE in migraine therapy.     

One‐component benzoxazine type photoinitiator for free radical polymerization

Synthesis of the Benzoxazine based benzophenone (BPBnzx) initiator was achieved and used in free radical photopolymerization of methylmethacrylate (MMA) in the absence and presence of a tertiary amine. The results confirmed that BPBnzx presents a one‐component nature. BPBnzx has better absorption properties compared with BP itself and the one‐component characteristic of the BPBnzx initiator was confirmed by incorporation of the BPBnzx unit into the polymethylmethacrylate (PMMA) main chain, using UV spectroscopy and phosphorescence measurements. POLYM. ENG. SCI., 2012. © 2011 Society of Plastics Engineers     

The investigation of photoinitiated polymerization of multifunctional acrylates with TX-BT by Photo-DSC and RT-FTIR

Photopolymerization of multifunctional acrylates with 3H-5-Thia-1,2,3-triaza-cyclopenta[b]anthracene-10-one (TX-BT) as the one-component photoinitiator was investigated using real-time Fourier transform infrared spectroscopy (RT-FTIR). Photo-differential scanning calorimetric (Photo-DSC) technique was used to study the gelation of trimethylolpropanetriacrylate (TMPTA), P-3038 (epoxydiacrylate (EA) 75% and tripropyleneglycoldiacrylate (TPGDA) 25%) and tripropyleneglycol diacrylate (TPGDA) + P-3038 in the presence of TX-BT. Photopolymerization reactions were performed under different conditions of initiator concentration and UV light intensity.     

Pressure-driven water flow through hydrophilic alumina nanomembranes

We present an experimental study that focuses on pressure-driven flow of distilled water through γ alumina membranes with 5, 10 and 20 nm pore radii. The nanopore geometry, pore size and porosity are characterized using scanning electron microscopy images taken pre- and post-flow experiments. Comparisons of these images have shown reduction in the pore size, which is attributed to precipitation of hydroxyl groups on alumina surfaces. Measured flowrates compared with the Hagen–Poiseuille flow relations consistently predict 2.2 nm reductions in the pore size for three different membranes. This behavior can be explained by the formation of a thick stick layer of water molecules over hydroxylated alumina surfaces, evidenced by water droplet contact angle measurements that exhibit increased hydrophilicity of alumina surfaces. Other possible effects of the mismatch between theory and experiments such as unaccounted pressure losses in the system or the streaming potential effects were also considered, but shown to be negligible for current experimental conditions.     

Tuning pH sensitivities of zinc phthalocyanines in ionic liquid modified matrices

Phthalocyanine dyes are clinically important bright fluorophores with many desirable properties. Their absorption and emission maxima in near infrared region make them proper tool for optical probing of biologically relevant materials and optical-chemical-sensing purposes. In this work we have shown that pH sensitivities of the phthalocyanines can be manipulated as desired. This property makes the Pcs very proper photosensitizers for photodynamic therapy applications. In this work pH sensitivities of alpha (α) and beta (β) tetra-substituted zinc phthalocyanines (ZnPcs) were studied spectroscopically in ethyl cellulose and PVC matrices. In experiments designed to manipulate pH, lipophilic room temperature ionic liquids (RTILs) were added into the test environment. The RTIL-modified thin films provided higher relative fluorescence intensity changes upon exposure to proton with respect to the RTIL-free ones. By this way, acidity constants of the ZnPcs could be tuned to the desired region of interest. The ZnPcs, exhibited good reproducibility and reversibility upon protonation. The RTILs also enhanced short and long term stabilities of the Pc-dyes. There was no significant drift in their proton sensitivities even after 10 assays and after being stored in a buffer condition for over six months.     

Simultaneous spectroscopic and topographic near-field imaging of TiO2 single surface states and interfacial electronic coupling

We have probed single surface states and the involved interfacial charge transfer coupling on the TiO(2) surface using confocal as well as tip-enhanced near-field topographic-spectroscopic imaging analysis on a niobium-doped rutile TiO(2)(110) surface. The confocal images excited with a radially polarized donut mode render ring-shaped excitation patterns typical for quantum systems with two perpendicular transition dipole moments. The tip-enhanced near-field optical images of single surface states are visualized by the strong exciton plasmon-polariton coupling localized at the subdomain boundaries with a spatial resolution of ～15 nm (far beyond the optical diffraction limit). We suggest that the abundant surface states in the doped TiO(2) generate excitons under laser excitation which are strongly coupled to the surface plasmon-polaritons of the Au tip. Moreover, the interfacial electronic molecule-substrate coupling has been characterized by probing the molecule-perturbed surface states distribution and the associated specific Raman vibrational modes. The imaging and characterization of the surface states and their distributions on TiO(2) surfaces at nanoscale are critically relevant to a deep understanding of interfacial electron transfer dynamics and energetics involving in solar energy conversion, photocatalysis, and mechanistic understanding of surface-enhanced Raman scattering spectroscopy.     

In situ polymerization of polyamide 66 nanocomposites utilizing interfacial polycondensation. III. Co‐synthesis of silica nanocomposites via sol–gel chemistry

In situ co‐synthesis of nylon 66 (PA66)‐silica nanocomposites can be accomplished through sol–gel chemistry conducted simultaneously with the nylon polymerization. Unfunctionalized silica nanocomposites and bonded silica nanocomposites wherein the inorganic silica phase chemically couples to the nylon polymer through a functionalized silane are generated via the simultaneous initiation of synthesis reactions in the inorganic and organic species. The effects of agitation and water‐to‐silane molar ratio on the courses of the inorganic and organic reactions and the generated silica morphology in the resulting nanocomposites are investigated using the tools of Brookfield Viscometer, Fourier transform infrared spectroscopy, and transmission electron microscopy. Dynamic mechanical analysis confirms the mechanical reinforcement of the various nanocomposites in relation to their silica content and network morphology. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers