Advanced Technologies for Oral Controlled Release: Cyclodextrins for oral controlled release

Cyclodextrins (CDs) are used in oral pharmaceutical formulations, by means of inclusion complexes formation, with the following advantages for the drugs: (1) solubility, dissolution rate, stability and bioavailability enhancement; (2) to modify the drug release site and/or time profile; and (3) to reduce or prevent gastrointestinal side effects and unpleasant smell or taste, to prevent drug-drug or drug-additive interactions, or even to convert oil and liquid drugs into microcrystalline or amorphous powders. A more recent trend focuses on the use of CDs as nanocarriers, a strategy that aims to design versatile delivery systems that can encapsulate drugs with better physicochemical properties for oral delivery. Thus, the aim of this work was to review the applications of the CDs and their hydrophilic derivatives on the solubility enhancement of poorly water soluble drugs in order to increase their dissolution rate and get immediate release, as well as their ability to control (to prolong or to delay) the release of drugs from solid dosage forms, either as complexes with the hydrophilic (e.g. as osmotic pumps) and/ or hydrophobic CDs. New controlled delivery systems based on nanotechonology carriers (nanoparticles and conjugates) have also been reviewed

Optoelectronic characterization of CuInGa(S)2 thin films grown by spray pyrolysis for photovoltaic application

[EN] Copper-indium gallium disulfide (CIGS) is a good absorber for photovoltaic application. Thin films of CIGS were prepared by spray pyrolysis on glass substrates in the ambient atmosphere. The films were characterized by different techniques, such as structural, morphological, optical and electrical properties of CIGS films were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), spectrophotometer and Hall effect, respectively. After optimization, the deposited films structure, grain size, and crystallinity became more important with an increase of annealing time at 370 degrees C for 20 min. Transmission electron microscopy (TEM) analysis shows that the interface sheets are well crystallized and the inter planer distance are 0.25 nm, 0.28 nm, and 0.36 nm. The atomic force microscopy (AFM) observation shows that the grain size and roughness can be tolerated by optimizing the annealing time. The strong absorbance and low transmittance were observed for the prepared films with a suitable energy bandgap about 1.46 eV. The Hall effect measurement system examined that CIGS films exhibited optimal electrical properties, resistivity, carrier mobility, and carrier concentration which were determined to be 4.22 x 10(6) omega cm, 6.18 x 10(2) cm(2) V-1 S-1 and 4.22 x 10(6) cm(-3), respectively. The optoelectronic properties of CIGS material recommended being used for the photovoltaic application.Prof. Bouchaib HARTITI, The Senior Associate at ICTP, is very grateful to ICTP for permanent support. Prof. Mohamed Ebn Touhami, Director of the University Center for Analysis, Expertise, Transfer of Technology and Incubation, Kenitra, Morocco, is very grateful to CUA2TI for financial support. Thanks to Doctor Diogo M.F. Santos for the supervision of Amal Bouich's work during her research in CeFEMA research center. The authors also thank researchers from CeFEMA (IST-ULisboa, Portugal) and CUA2TI (FS-Kenitra Morocco) for their help.Bouich, A.; Hartiti, B.; Ullah, S.; Ullah, H.; Ebn Touhami, M.; Santos, DMF.; Marí, B. (2019). Optoelectronic characterization of CuInGa(S)2 thin films grown by spray pyrolysis for photovoltaic application. Applied Physics A. 125(8):1-9. https://doi.org/10.1007/s00339-019-2874-4S191258T. Feurer, P. Reinhard, E. Avancini, B. Bissig, J. Löckinger, P. Fuchs, S. Buecheler, Progress in thin film CIGS photovoltaics–Research and development, manufacturing, and applications. Prog. Photovolt. Res. Appl. 25(7), 645–667 (2017)A. Zegadi, M.A. Slifkin, M. Djamin, A.E. Hill, R.D. Tomlinson, A photoacoustic study of CuInxGa1− xSe2 alloys. Phys. Status Solidi (A) 133(2), 533–540 (1992)T.H. Sajeesh, A.R. Warrier, C.S. Kartha, K.P. Vijayakumar, Optimization of parameters of chemical spray pyrolysis technique to get n and p-type layers of SnS. Thin Solid Films 518(15), 4370–4374 (2010)J. Liu, D. Zhuang, H. Luan, M. Cao, M. Xie, X. Li, Preparation of Cu (In, Ga) Se2 thin film by sputtering from Cu (In, Ga) Se2 quaternary target. Progr. Nat. Sci. Mater. Int. 23(2), 133–138 (2013)M.I. Hossain, Fabrication and characterization of CIGS solar cells with In2 S3 buffer layer deposited by PVD technique. Chalcogenide Lett. 9(5), 185–191 (2012)M.A. Mughal, R. Engelken, R. Sharma, Progress in indium (III) sulfide (In2S3) buffer layer deposition techniques for CIS, CIGS, and CdTe-based thin film solar cells. Sol. Energy 120, 131–146 (2015)M. Powalla, M. Cemernjak, J. Eberhardt, F. Kessler, R. Kniese, H.D. Mohring, B. Dimmler, Large-area CIGS modules: Pilot line production and new developments. Sol. Energy Mater Sol. Cells 90(18–19), 3158–3164 (2006)M.E. Calixto, P.J. Sebastian, R.N. Bhattacharya, R. Noufi, Compositional and optoelectronic properties of CIS and CIGS thin films formed by electrodeposition. Sol. Energy Mater. Sol. Cells 59(1–2), 75–84 (1999)S. Jung, S. Ahn, J.H. Yun, J. Gwak, D. Kim, K. Yoon, Effects of Ga contents on properties of CIGS thin films and solar cells fabricated by co-evaporation technique. Curr. Appl. Phys. 10(4), 990–996 (2010)S. R. Ovshinsky, X. Deng, R. Young, U.S. Patent No. 5,231,047. Washington, DC: U.S. Patent and Trademark Office (1993).M. Kaelin, D. Rudmann, A.N. Tiwari, Low cost processing of CIGS thin film solar cells. Sol. Energy 77(6), 749–756 (2004)Fangdan Jiang, Jiayou Feng, Effect of temperature on selenization process of metallic Cu–In alloy precursors. Thin Solid Films 515(4), 1950–1955 (2006)S. Shirakata, Y. Kannaka, H. Hasegawa, T. Kariya, S. Isomura, Properties of Cu (In, Ga) Se2 thin films prepared by chemical spray pyrolysis. Jpn. J. Appl. Phys. 38(9R), 4997 (1999)Y.K. Kumar, G.S. Babu, P.U. Bhaskar, V.S. Raja, Effect of starting-solution pH on the growth of Cu2ZnSnS4 thin films deposited by spray pyrolysis. Phys. Status Solidi (A) 206(7), 1525–1530 (2009)M. Ajili, M. Castagné, N.K. Turki, Characteristics of CuIn1− xGaxS2 thin films synthesized by chemical spray pyrolysis. J. Lumin. 150, 1–7 (2014)B.J. Babu, S. Velumani, A. Kassiba, R. Asomoza, J.A. Chavez-Carvayar, J. Yi, Deposition and characterization of graded Cu (In1-xGax) Se2 thin films by spray pyrolysis. Mater. Chem. Phys. 162, 59–68 (2015)S.F. Varol, G. Babür, G. Çankaya, U. Kölemen, Synthesis of sol–gel derived nano-crystalline ZnO thin films as TCO window layer: effect of sol aging and boron. RSC Adv. 4(100), 56645–56653 (2014)J.A. Frantz, R.Y. Bekele, V.Q. Nguyen, J.S. Sanghera, A. Bruce, S.V. Frolov, I.D. Aggarwal, Cu (In, Ga) Se2 thin films and devices sputtered from a single target without additional selenization. Thin Solid Films 519(22), 7763–7765 (2011)C. Calderón, G. Gordillo, P. Bartolo-Pérez, F. Mesa, Effect of the deposition conditions on the optical, morphological and compositional properties of CuIn1− xGaxSe2 thin films prepared by a multistage process. Revista Mexicana de Física 53(7), 270–273 (2007)D. Schmid, M. Ruckh, F. Grunwald, H.W. Schock, Chalcopyrite/defect chalcopyrite heterojunctions on the basis of CuInSe2. J. Appl. Phys. 73(6), 2902–2909 (1993)U.C. Matur, S. Akyol, N. Baydoğan, H. Cimenoglu, The optical properties of CIGS thin films derived by sol-gel dip coating process at different withdrawal speed. Proc. Soc. Behav. Sci. 195, 1762–1767 (2015)A. Bouich, B. Hartiti, S. Ullah, M.E. Touhami, B. Mari, D.M.F. Santos, Investigation of the optical properties of CuIn (Se, S)2 thin films for photovoltaic application. Mater. Today Proc. 13, 663–669 (2019)K. Matsumura, T. Fujita, H. Itoh, D. Fujita, Characterization of carrier concentration in CIGS solar cells by scanning capacitance microscopy. Meas. Sci. Technol. 25(4), 044020 (2014)A. Bouich, B. Hartiti, S. Ullah, H. Ullah, M.E. Touhami, D.M.F. Santos, B. Mari, Experimental, theoretical, and numerical simulation of the performance of CuInxGa(1–x) S2 based solar cells. Optik 183, 137–147 (2019

Antimony-Doped Tin(II) Sulfide Thin Films

Thin-film solar cells made from earth-abundant, inexpensive, and nontoxic materials are needed to replace the current technologies whose widespread use is limited by their use of scarce, costly, and toxic elements. Tin monosulfide (SnS) is a promising candidate for making absorber layers in scalable, inexpensive, and nontoxic solar cells. SnS has always been observed to be a p-type semiconductor. Doping SnS to form an n-type semiconductor would permit the construction of solar cells with p-n homojunctions. This paper reports doping SnS films with antimony, a potential n-type dopant. Small amounts of antimony (1%) were found to greatly increase the electrical resistance of the SnS. The resulting intrinsic SnS(Sb) films could be used for the insulating layer in a p-i-n design for solar cells. Higher concentrations (5%) of antimony did not convert the SnS(Sb) to low-resistivity n-type conductivity, but instead the films retain such a high resistance that the conductivity type could not be determined. Extended X-ray absorption fine structure analysis reveals that the highly doped films contain precipitates of a secondary phase that has chemical bonds characteristic of metallic antimony, rather than the antimony–sulfur bonds found in films with lower concentrations of antimony.United States. Dept. of Energy. Sunshot Initiative (Contract DE-EE0005329)National Science Foundation (U.S.) (Grant CBET-1032955

Spray Pyrolysed Tin Chalcogenide Thin Films: Optimization of optoelectronic properties of SnS for possible photovoltaic application as an absorber layer

In the early 19th century, industrial revolution was fuelled mainly by the development of machine based manufacturing and the increased use of coal. Later on, the focal point shifted to oil, thanks to the mass-production technology, ease of transport/storage and also the (less) environmental issues in comparison with the coal!! By the dawn of 21st century, due to the depletion of oil reserves and pollution resulting from heavy usage of oil the demand for clean energy was on the rising edge. This ever growing demand has propelled research on photovoltaics which has emerged successful and is currently being looked up to as the only solace for meeting our present day energy requirements. The proven PV technology on commercial scale is based on silicon but the recent boom in the demand for photovoltaic modules has in turn created a shortage in supply of silicon. Also the technology is still not accessible to common man. This has onset the research and development work on moderately efficient, eco-friendly and low cost photovoltaic devices (solar cells). Thin film photovoltaic modules have made a breakthrough entry in the PV market on these grounds. Thin films have the potential to revolutionize the present cost structure of solar cells by eliminating the use of the expensive silicon wafers that alone accounts for above 50% of total module manufacturing cost.Well developed thin film photovoltaic technologies are based on amorphous silicon, CdTe and CuInSe2. However the cell fabrication process using amorphous silicon requires handling of very toxic gases (like phosphene, silane and borane) and costly technologies for cell fabrication. In the case of other materials too, there are difficulties like maintaining stoichiometry (especially in large area films), alleged environmental hazards and high cost of indium. Hence there is an urgent need for the development of materials that are easy to prepare, eco-friendly and available in abundance. The work presented in this thesis is an attempt towards the development of a cost-effective, eco-friendly material for thin film solar cells using simple economically viable technique. Sn-based window and absorber layers deposited using Chemical Spray Pyrolysis (CSP) technique have been chosen for the purposeCochin University of Science and TechnologyDepartment of Physics Cochin University of Science and Technolog

Spray Pyrolysed Tin Chalcogenide Thin Films: Optimization of optoelectronic properties of SnS for possible photovoltaic application as an absorber layer

In the early 19th century, industrial revolution was fuelled mainly by the development of machine based manufacturing and the increased use of coal. Later on, the focal point shifted to oil, thanks to the mass-production technology, ease of transport/storage and also the (less) environmental issues in comparison with the coal!! By the dawn of 21st century, due to the depletion of oil reserves and pollution resulting from heavy usage of oil the demand for clean energy was on the rising edge. This ever growing demand has propelled research on photovoltaics which has emerged successful and is currently being looked up to as the only solace for meeting our present day energy requirements. The proven PV technology on commercial scale is based on silicon but the recent boom in the demand for photovoltaic modules has in turn created a shortage in supply of silicon. Also the technology is still not accessible to common man. This has onset the research and development work on moderately efficient, eco-friendly and low cost photovoltaic devices (solar cells). Thin film photovoltaic modules have made a breakthrough entry in the PV market on these grounds. Thin films have the potential to revolutionize the present cost structure of solar cells by eliminating the use of the expensive silicon wafers that alone accounts for above 50% of total module manufacturing cost

EVALUATION OF ANTIOXIDANT AND ANTIMICROBIAL ACTIVITIES OF TARENNA ASIATICA (L.) O. KTZE. EX K. SCHUM.

Objective: The study was aimed to analyze the phytochemical, antioxidant and antibacterial potentials of T. asiatica.Methods: The leaves, barks and flowers extracts were analyzed for total phenolic and flavonoid contents. Antioxidant activities were evaluated using DPPHâ— scavenging, ABTSâ—+ scavenging, FRAP, phosphomolybdenum reduction, metal chelating, nitric oxide radical scavenging, superoxide radical scavenging, hydroxyl radical scavenging and lipid peroxidation assays. Antibacterial activity was examined using agar well diffusion method against pathogenic microorganisms.Results: The total phenolic and flavonoid contents were found to be higher in acetone extract of leaves (57.21 g GAE/100 g and 619.67 mg RE/g respectively). Antioxidant assays revealed that leaves acetone extract possesses significant (p<0.05) DPPHâ— scavenging capacity (IC50: 20.38 µg/mL), ABTSâ—+ scavenging activity (10435.44 µM TE/g), ferric reducing activity (152.13 mM Fe(II)E/mg), phosphomolybdenum reduction (417.93 mg AAE/g) and metal chelating activity (20.85 g EDTAE/100 g). At a concentration of 200 ug/mL, the leaves acetone extract also showed higher nitric oxide radical (49.22percent), superoxide radical (73.63percent) and hydroxyl radical (69.04percent) scavenging activities and inhibition for lipid peroxidation (57.38percent). Leaves and flowers acetone extracts inhibited the growth of S. dysenteriae, B. subtilis and S. boydii with an inhibition zone ≥12 mm. MIC of flowers acetone extract was found to be 20 µg/mL against both B. subtilis and S. boydii.Conclusion: T. asiatica contains considerable phenolic and flavonoid contents which is responsible for the evident antioxidant and antimicrobial activities. These findings validate that T. asiatica can be a natural antioxidant and antibacterial source which will address medical security.KeywordsAntimicrobial, Antioxidant, Flavonoid, Free radical, Phenolic, Reactive oxygen species, Tarenna asiatic

Ensuring The Homogeneity OF Spray Pyrolised SnS Thin Films Employing XPS Depth Profiling

SnS thin films were prepared using chemical spray pyrolysis (CSP) technique. p-type SnS films with direct band gap of 1.33 eV and having very high absorption coefficient were obtained with the optimized deposition conditions. In this paper we focus on investigating the uniformity and phase purity of the hence deposited SnS films employing Raman and X-ray Photoelectron Spectroscopy (XPS) analysis. Raman Spectra of the films had only single peak corresponding to the Raman active Ag mode at 224 cm(-1) which is characteristic for phase-pure SnS thin films. Detailed XPS analysis on these samples were performed by scanning the peaks for Sn, S, and O with high resolution to estimate the chemical states and composition. Employing Ar-ion sputtering, the depth profiles showing variation in concentration and binding energies of S, Sn, O over the sample thickness were obtained and the uniformity in composition along the thickness has been discussed in detail

Optimization of parameters of chemical spray pyrolysis technique to get n and p-type layers of SnS

SnS thin films were prepared using automated chemical spray pyrolysis (CSP) technique. Single-phase, p-type, stoichiometric, SnS films with direct band gap of 1.33 eV and having very high absorption coefficient (N105/cm) were deposited at substrate temperature of 375 °C. The role of substrate temperature in determining the optoelectronic and structural properties of SnS films was established and concentration ratios of anionic and cationic precursor solutions were optimized. n-type SnS samples were also prepared using CSP technique at the same substrate temperature of 375 °C, which facilitates sequential deposition of SnS homojunction. A comprehensive analysis of both types of films was done using x-ray diffraction, energy dispersive x-ray analysis, scanning electron microscopy, atomic force microscopy, optical absorption and electrical measurements. Deposition temperatures required for growth of other binary sulfide phases of tin such as SnS2, Sn2S3 were also determinedCochin University of Science and TechnologyThin Solid Films 518 (2010) 4370–437

Role of pH of precursor solution in taming the material properties of spray pyrolysed SnS thin films

Samples were deposited using chemical spray pyrolysis technique by varying the pH of the starting precursor solution from 0.8 to 3.2. These samples were analyzed using X- ray diffraction, optical absorption spectroscopy, energy dispersive X-ray analysis, scanning electron microscopy, and electrical measurements in order to investigate the role of pH of the precursor solution on structural, morphological, electrical and optical properties of the SnS films. From the study we could optimize the pH of precursor solution required for the deposition of device quality SnS thin films. Resistivity of the films was brought down by three orders (to 6 × 10−2 Ω cm) along with enhancement in grain size as well as photosensitivity by optimizing the pH of the precursor solution alone. Band gap of the films could also be tailored by controlling the pH of the precursor solution