Different Combinations Of Polymers Research Articles

Formulation, optimization and evaluation of levocetirizine dihyrochloride oral thin strip

The aim of present research was to develop a fast releasing oral polymeric film, with good mechanical properties, instant disintegration and dissolution, producing an acceptable taste when placed on tongue. Solvent casting method was used to prepare oral films. Levocetirizine dihydrochloride, an antihistaminic was incorporated to relieve the symptoms of allergic rhinitis. The polymers selected were HPMC E 15 and PVA. Propylene glycol was the plasticizers used. Nine batches of films with drug were prepared using different combinations of polymers and plasticizer concentration. The resultant films were evaluated for weight variation, content uniformity, folding endurance, thickness, surface pH, in vitro disintegration and in vitro dissolution. The optimized films which disintegrated in less than 30 sec, releasing 85-98% of drug within 2 minutes. The percentage release was varying with concentration of plasticizer and polymer. The films made with HPMC: PVA (1:2) released 96% of drug in 1 min, which was the best release amongst all.

Effect of Rupturable and Erodible Polymers in the Outer Shell of Press Coated Tablet.

As a new oral chronopharmaceutical drug delivery system for asthma were developed by using press-coating technology. Tablets composed of an outer shell by using different rupturable and erodible polymers and their combination and core tablet containing Montelukast sodium as a model drug. Press coated tablets with different weight ratio of HPC (EXF) and Ethyl Cellulose (N22); as an outer coating shell and Starlac was used as filler binder in core tablet were examined for change in time lag and release pattern of Montelukast sodium. Press coated tablets were evaluated for thickness, hardness, friability, weight variation and in vitro dissolution test. The study showed different release pattern can be obtained from changing the coating composition. The results also showed that press coated tablets, comprising of a core tablet containing drug, an outer shell of different combinations of polymers, showed acid resistance and time-released functions on in vitro dissolution study.

Formulation development of fast releasing oral thin films of levocetrizine dihydrochloride with Eudragit® Epo and optimization through Taguchi orthogonal experimental design

The aim of this study was to develop a fast releasing oral polymeric film, prepared using the solvent casting method, with good mechanical properties, instant disintegration and dissolution, an acceptable taste in the oral cavity. Levocetirizine dihydrochloride, an antihistamine, was incorporated to relieve the symptoms of allergic rhinitis. Four batches of films with drug were prepared using different combinations of polymers and plasticizers Eudragit® EPO, HPMC E 5 LV, and PVA were the selected polymers. Glycerin, dibutyl phthalate, propylene glycol, and PEG 400 were the selected plasticizers.The resultant films were evaluated for weight variation, assay, content uniformity, folding endurance, thickness, tensile strength, percent elongation, surface pH, in vitro disintegration and in vitro dissolution.The formulations from the preliminary trial were analyzed using Taguchi OA experimental design, which was applied to optimize the type of polymers, concentration of polymers, plasticizer, and sweetener based on their disintegration data at three different levels.The optimized films disintegrated in less than 30s, releasing 70-90% of drug within 2 mins.The percentage release varied with the type of polymer and concentration of polymer. The films made with EPO released 96% of drug in 2 mins, which was the best release among all.

Interfacial energy between carbon nanotubes and polymers measured from nanoscale peel tests in the atomic force microscope

The future development of polymer composite materials with nanotubes or nanoscale fibers requires the ability to understand and improve the interfacial bonding at the nanotube–polymer matrix interface. In recent work [Strus MC, Zalamea L, Raman A, Pipes RB, Nguyen CV, Stach EA. Peeling force spectroscopy: exposing the adhesive nanomechanics of one-dimensional nanostructures. Nano Lett 2008;8(2):544–50], it has been shown that a new mode in the Atomic Force Microscope (AFM), peeling force spectroscopy, can be used to understand the adhesive mechanics of carbon nanotubes peeled from a surface. In the present work, we demonstrate how AFM peeling force spectroscopy can be used to distinguish between elastic and interfacial components during a nanoscale peel test, thus enabling the direct measurement of interfacial energy between an individual nanotube or nanofiber and a given material surface. The proposed method provides a convenient experimental framework to quickly screen different combinations of polymers and functionalized nanotubes for optimal interfacial strength.

Novel One-Pot Synthesis of Magnetite Latex Nanoparticles by Ultrasound Irradiation

A simple and efficacious procedure for the synthesis of magnetite nanoparticles has been achieved via a sonochemical miniemulsion polymerization process. The sonochemically synthesized magnetite encapsulated polymer latex particles exhibit excellent colloidal stability and strong magnetic properties, and are of a size that makes them technologically relevant. This novel method may be readily extended to the preparation of multiple combinations of different polymers and encapsulated materials.

A small-angle neutron scattering and rheology study of the composite of chitosan and gelatin

The composite chitosan/gelatin solutions and films formed from these solutions were studied by rheological measurements, SANS and tensile tests. The relationship between the inter-molecule interactions with microstructure, rheological behaviour of a solution and eventually the mechanical performance of formed films was established. It was found that the complex formed between chitosan and gelatin was mainly through hydrogen bond but the size of the structure was also affected by electrostatic repulsions. The local structure (correlation length) and the global structure (large inhomogeneous structure size) in the composite solutions were found to be highly correlated to each other. It was also found that the interactions between these two polymers in solution were closely related to the mechanical properties of the formed films. This work will enable one to design films with desired mechanical properties through the combination of different polymers at optimum weight ratios.

Toughness optimization of glass‐fiber reinforced PA 6/PA 66‐based composites: Effect of matrix composition and colorants

AbstractMixing of polyamide 6 (PA 6) and polyamide 66 (PA 66) is integrated in the trend of development of new and improved materials by combination of different polymers and some reinforcing materials to polymer composites. The specific polymer composite PA 6/PA 66 reinforced with short glass‐fibers combines the good coloring of PA 6, and the small moisture absorption of PA 66. Technical applications of PA 6/PA 66 composites are mainly used in the automotive industry. Specific requirements of this industry lead to the necessity to optimize the material resistance against crack propagation of the PA 6/PA 66 composites, using mechanical and fracture mechanical methods. So, the present investigations focus on fracture mechanics toughness optimization of the PA 6/PA 66 composites, including unstable and stable crack growth. The aim of this toughness optimization is to find out the optimal mixing ratio of PA 6/PA 66. Applications of PA 6/PA 66 in the automotive industry and specific client wishes are the main reasons for black‐coloring of the PA materials. The influence of several black‐colorants (carbon black, nigrosine, spinel, iron oxide) on mechanical and fracture mechanical properties of the PA composites is also investigated using fracture mechanical methods. As experimental fracture mechanical method, preferentially, the instrumented Charpy impact test (ICIT) and the new cut method to determine the stable crack growth of glass‐fiber reinforced materials was used. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Transdermal delivery of trazodone hydrochloride from acrylic films prepared from aqueous latex

Trazodone hydrochloride has not been previously investigated and reported for potential administration through transdermal route. Therefore, the present investigation was carried out to study the effect of polymeric composition, drug content and plasticizer on the permeation of trazodone hydrochloride across the mouse epidermis for the development of transdermal therapeutic system. The pseudolatex films with different combination of polymers, plasticizer and drug were prepared from aqueous colloidal polymer dispersions. The polymers used were Eudragit RL100 and RS100. Triethylcitrate was used as plasticizer. The in vitro release and skin permeation through mouse epidermis from the prepared films were studied using Keshary-Chien diffusion cell. The in vitro drug release increased with increasing amount of Eudragit RL100 in the film. It was observed that the maximum skin permeability was attained at a loading dose of 10% w/w in the film. The in vitro flux decreased gradually at higher concentration up to 13% w/w. The present study has demonstrated the potential of the fabricated pseudolatex transdermal films for sustained release of trazodone hydrochloride. The concentration of triethylcitrate in the film markedly affected the skin permeation properties of trazodone hydrochloride.

Analysis of retrieved polymer fiber based replacements for the ACL

The present retrospective analysis of 117 surgically excised anterior cruciate ligament (ACL) prostheses was designed to elucidate the etiology and mechanisms of failure of synthetic ligamentous prostheses. They were harvested from young and active patients (26±7 yrs) at various orthopaedic centers in France between 1983 and 1993. The average duration of implantation of augmentation and replacement prostheses were 21.5±12.6 and 33.2±25.3 months, respectively. The principal causes for their excision were ruptures and synovitis. Each ACL prosthesis was examined macroscopically, histologically, and, after tissue removal, by scanning electron microscopy (SEM) to determine the model, manufacturer, surgical technique used at implantation, the extent of healing, the site of rupture, and the morphology of the damaged fibers. Fourteen types of ACL prostheses were analysed, each fabricated using a different combination of polymers, fibers and textile constructions. Consequently, they generated a variety of healing characteristics and mechanical responses in vivo. SEM observations revealed that abrasion of the textile fibers as a result of yarn-on-yarn and/or yarn-on-bone contact was a common phenomenon to almost all models, and was the primary cause of prosthetic failure. Healing inside the synthetic ACL was poorly organized, incomplete and unpredictable as the extent of collagenous infiltration into the textile structure did not increase with the duration of implantation. In fact, the collagenous infiltration into certain models appeared to be more detrimental than beneficial since it caused deterioration and fraying of the textile structure rather than serving as a reinforcing matrix around the prosthesis. In conclusion, the present study shows that three mechanisms may be involved in the failure of ACL prostheses: (1) inadequate fiber abrasion resistance against osseous surfaces; (2) flexural and rotational fatigue of the fibers, and (3) loss of integrity of the textile structure due to unpredictable tissue infiltration during healing.

Optical waveguiding in thin films of polyelectrolytes

Planar waveguides were prepared by spin-coating of polyelectrolytes, a class of polymers that is also called ionenes, to characterize their linear optical properties. A prism-coupler experiment was used to evaluate the refractive index n at different wavelengths. The dispersion of n was calculated from the absorption spectrum by means of the Kramers-Kronig relations. Adjusting the parameters of the Kramers-Kronig analysis to the measured n allows the determination of the influence of the polymer backbone and its separation from contributions of the counterions. Using different combinations of polymers and counterions, a range of n between 1.57 and 1.72 with Abbe numbers nu D between nu D=13 and nu =65 can be achieved. The birefringence of these films was found to be less than 0.001 as derived from comparison of TE and TM modes. The waveguide losses were measured by monitoring the stray light of the films with a diode array. The attenuation coefficients were studied at various laser wavelengths and waveguide modes. Attenuation coefficients in the region of 1 dB cm-1 were achieved.