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Nanoparticle Synthesis and Administration Routes for Antiviral Uses
Published in Devarajan Thangadurai, Saher Islam, Charles Oluwaseun Adetunji, Viral and Antiviral Nanomaterials, 2022
João Augusto Oshiro-Júnior, Kammila Martins Nicolau Costa, Isadora Frigieri, Bruna Galdorfini Chiari-Andréo
Considering the use of polymers in the formulation, a glass transition temperature is observed in DSC, as well as a decomposition temperature of the drug present in the nanosystem (Yang et al. 2016a). DSC was used as a characterization technique for nanoparticles containing both embedded lamivudine and efavirenz, showing results of molecular interaction between the drug and the polymer used in the formulation and chemical stability (Cojocaru et al. 2020).
Spray Drying and Pharmaceutical Applications
Published in Dilip M. Parikh, Handbook of Pharmaceutical Granulation Technology, 2021
Metin Çelik, Pavan Muttil, Gülşilan Binzet, Susan C. Wendell
Glass transition temperature (Tg): Glass transition temperature is an important thermophysical property of amorphous polymers. Above Tg, the material changes from a rigid glassy state to a more rubbery state. Hence, this could be related somehow with the material stickiness on the drying chamber, being, therefore, an obstacle to the spray drying process.
Versatile Nature of Poly(Vinylpyrrolidone) in Clinical Medicine
Published in P. Mereena Luke, K. R. Dhanya, Didier Rouxel, Nandakumar Kalarikkal, Sabu Thomas, Advanced Studies in Experimental and Clinical Medicine, 2021
K. R. Dhanya, P. Mereena Luke, Sabu Thomas, Didier Rouxel, Nandakumar Kalarikkal
PVP is soluble in all types of organic solvents and under normal conditions and is quite stable. The reason behind this remarked solubility is that they contain both hydrophilic and hydrophobic groups in the chain structure. The inert, hygroscopic, colorless, and temperature resistant behavior of PVP makes it a unique polymer [87, 88]. The glass transition temperature is related with its molecular weight. PVP films are fairly hard and transparent. Binding with natural as well as synthetic resins, PVP forms clear films. Chemically modified PVP are extremely inert in nature. In powder state, it is comparatively stable and if applying temperature on PVP, it becomes yellow in color. PVP is in contact with light, the formation of gelation happens.
Antifouling properties of amphiphilic poly(3-hydroxyalkanoate): an environmentally-friendly coating
Published in Biofouling, 2021
A. Guennec, L. Brelle, E. Balnois, I. Linossier, E. Renard, V. Langlois, F. Faÿ, G. Q. Chen, C. Simon-Colin, K. Vallée-Réhel
1H NMR spectra in CDCl3 were recorded at room temperature using a Bruker 400 MHz NMR spectrometer (Billerica, MA, USA). Average molar masses were determined by SEC experiments using Spectra Physics P100 pump and two PL-gel columns A Wyatt Technology Optilab rEX interferometric refractometer was used as the detector. Chloroform was chosen as the eluent at a flow rate of 1 ml min−1 and polystyrene standards were used for calibration. Thermal properties were determined using DSC-25 calorimeter from TA Instruments (New Castle, DE, USA) under nitrogen atmosphere. All the samples were analyzed between −70 °C and 200 °C with a heating rate of 10 °C min−1. After a rapid cooling from 200 °C to −70 °C (at 10° min−1) they were heated again to 200 °C with a heating rate of 10 °C min−1. The melting temperature (Tm) and melting enthalpy (ΔHm) were determined during the first heating run whereas the glass transition temperature (Tg) was determined at the second heating run. Structural characterization was obtained by X-Ray diffraction (XRD) using D8 Advance Bruker diffractometer (Billerica, MA, USA) with Cu Kα radiation operated at 30 kV and 30 mA. Xray diffraction measurements were recorded over a 2θ range from 5 to 60° by a step 0.017° at an incident wavelength (λ) of 1.542 Ǻ.
Physical stability of dry powder inhaler formulations
Published in Expert Opinion on Drug Delivery, 2020
Nivedita Shetty, David Cipolla, Heejun Park, Qi Tony Zhou
DSC is another solid-state characterization technique which measures the glass transition temperature (Tg) and helps in the identification of melting, crystallization, degree of crystallinity and thermal transition phenomena. Glass transition temperature is the temperature at which a transition from a ‘glassy state’ to a ‘rubbery state’ occurs in an amorphous material. The unique advantage of the DSC technique is its rapid analysis time and that it requires only a nominal sample. However, two major disadvantages of using DSC for measuring Tg are its relatively low sensitivity and the possibility that multiple thermal events may occur and overlap or interfere with the determination of the glass transition [183]. To overcome these limitations of conventional DSC, the modulated DSC (mDSC) was introduced more than two decades ago and has been used to characterize amorphous solids [184]. Both DSC and PXRD can quantify moderate-to-high levels of amorphous materials whereas DVS is more sensitive and can detect very low amounts of amorphous content [48].
Gel network comprising UV crosslinked PLGA-b-PEG-MA nanoparticles for ibuprofen topical delivery
Published in Pharmaceutical Development and Technology, 2019
Ipek Eroglu, Merve Gultekinoglu, Cem Bayram, Acelya Erikci, Samiye Yabanoglu Ciftci, Eda Ayse Aksoy, Kezban Ulubayram
The DSC analysis has revealed that glass transition temperature (Tg) for all the formulations were above the body temperature and this makes this systems suitable for drug delivery purposes. Tg of PLGA-b-PEG nanoparticles and PLGA-b-PEG gel network was found to be 43 °C and ≈52 °C, respectively. The UV crosslinking of nanoparticles resulted in the shift of Tg to a higher temperature due to the decreased interspaces between the polymeric chains. Meanwhile, secondary transitions also shifted to higher temperatures. DSC thermogram of ibuprofen recorded was found to match with the literature findings; a specific exothermic peak at 78 °C was observed and this is specific to ibuprofen. When the DSC thermogram of PLGA-b-PEG-MA nanoparticles was analyzed, effect of methacrylates on the macromolecule has been clearly observed (Figure 6). The transition peaks observed above 105 °C were specific to methacrylates whiles the peak shown at 133 °C represents melting peak for PLGA-b-PEG-MA nanoparticles. In addition to this, endothermic peak recorded at 185 °C represents the decomposition of the structure. The stereotaxic properties of the methacrylayed structure induced the crystallization of the amorphous structure and, therefore Tg was not observed. As a result, UV crosslinking resulted in the shifting of thermal properties and this situation may attributed to the existence of the ibuprofen loaded into the gel network structure in amorphous form instead of a crystal form.