Thermoanalytical study of purine derivatives compounds

Schnitzler, Egon; Kobelnik, Marcelo; Sotelo, G. F. C.; Bannach, Gilbert; Ionashiro, Massao

doi:10.1590/s0100-46702004000100009

Cited by 19 publications

(20 citation statements)

References 15 publications

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“…The relatively small amount of theophylline (13%) in the PM and nanofibers may explain why the melting of theophylline is not recognized in the DSC thermograms of PM or nanofibers, but it cannot account for the lack of thermic events during the cooling phase or in the second heating of pure theophylline. Crystallization of theophylline during the DSC cooling phase has been reported previously [13,16].…”

Section: Resultsmentioning

confidence: 86%

Comparison of Traditional and Ultrasound-Enhanced Electrospinning in Fabricating Nanofibrous Drug Delivery Systems

et al. 2019

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We investigated nozzleless ultrasound-enhanced electrospinning (USES) as means to generate nanofibrous drug delivery systems (DDSs) for pharmaceutical and biomedical applications. Traditional electrospinning (TES) equipped with a conventional spinneret was used as a reference method. High-molecular polyethylene oxide (PEO) and chitosan were used as carrier polymers and theophylline anhydrate as a water-soluble model drug. The nanofibers were electrospun with the diluted mixture (7:3) of aqueous acetic acid (90% v/v) and formic acid solution (90% v/v) (with a total solid content of 3% w/v). The fiber diameter and morphology of the nanofibrous DDSs were modulated by varying ultrasonic parameters in the USES process (i.e., frequency, pulse repetition frequency and cycles per pulse). We found that the USES technology produced nanofibers with higher fiber diameter (402 ± 127 nm) than TES (77 ± 21 nm). An increase of a burst count in USES increased the fiber diameter (555 ± 265 nm) and the variation in fiber size. The slight-to-moderate changes in a solid state (crystallinity) were detected when compared the nanofibers generated by TES and USES. In conclusion, USES provides a promising alternative for aqueous-based fabrication of nanofibrous DDSs for pharmaceutical and biomedical applications.

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Section: Resultsmentioning

confidence: 86%

Comparison of Traditional and Ultrasound-Enhanced Electrospinning in Fabricating Nanofibrous Drug Delivery Systems

et al. 2019

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“…The FT‐IR spectra from all samples and controls were evaluated but, as the different T inlet considered did not produce products with different spectra, only the spectra of the spray‐dried milk powders atomized at 105 °C are presented as an example (Figure ). Theophylline (raw material) showed bands at 3120.96 cm −1 (N–H stretching), at 1716.72 cm −1 and 1668.50 cm −1 (C=O stretching, amide I), at 1566.27 cm −1 (N–H bending, amide II) and the N–H wagging at 742.63 cm −1 . For the samples with milk, regardless the fat content, it was possible to identify bands at 3468.16–3304.20 cm −1 (O–H and N–H stretching in the protein structure), at 1660.78–1643.42 cm −1 and 1546.98–1545.05 cm −1 (amides I and II, respectively, in the proteins’ structure) and in the region of 1200–900 cm −1 , corresponding to the so‐called saccharide bands.…”

Section: Resultsmentioning

confidence: 99%

Production and characterization of spray-dried theophylline powders prepared from fresh milk for potential use in paediatrics

Aguiar

Fernandes

Nese

et al. 2016

Journal of Pharmacy and Pharmacology

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“…Earlier, Schneitzler et al [22] have reported TGA of purine derivatives such as aminophylline, theoophylline, caffeine and uric acid. It was found that uric acid was stable up to 375°C and thereafter the mass loss occurred through rapid process.…”

Section: Discussionmentioning

confidence: 99%

In vitro Growth and Inhibition Studies of Monosodium Urate Monohydrate Crystals by Different Herbal Extracts

Parekh¹,

Vasant²,

Tank³

et al. 2009

American Journal of Infectious Diseases

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Problem statement:A large number of people in the world have been suffering from gout for centuries. Gout is the term given to a metabolic condition in which the signs and symptoms results from the deposition of crystals of Monosodium Urate Monohydrate (MSUM) in various connective tissues. Approach: It was quite difficult to grow good quality large MSUM crystals because uric acid was having very low solubility in any known solvents. Results: Attempts were made in the present investigation to grow MSUM crystals in vitro by single diffusion gel growth technique, which is quite suitable to mimic the growth of MSUM crystals in vivo up to a certain extent. Good quality needle type crystals were grown in the gel, which were characterized by FT-IR, Powder X-ray diffraction and Thermo-gravimetry. The characterization study confirmed the formation of MSUM crystals in the experiments. Herbal extract solutions of Boswellia serrata Linn., Aerva lanata juss ex. Schult, Routula aquatica Lour. and Boerhavia diffusa Linn., were used for the growth inhibition study of MSUM crystals. Aqueous herbal extract solutions were poured as supernatant solutions along with the control solution on the set gels during the crystal growth experiment. The growth observations and the measurements of crystal dimensions using optical microscope suggested that Routula aquatica Lour. and Aerva lanata juss ex. Schult extracts exhibited good crystal growth inhibition results. Conclusion: Routula aquatica Lour. extract dissolved MSUM crystals after 15 days of pouring the supernatant solution on the gel. This in vitro study may be helpful for in vivo studies, which may further lead to develop a preclinical formulation for gout treatment.

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Thermoanalytical study of purine derivatives compounds

Cited by 19 publications

References 15 publications

Comparison of Traditional and Ultrasound-Enhanced Electrospinning in Fabricating Nanofibrous Drug Delivery Systems

Comparison of Traditional and Ultrasound-Enhanced Electrospinning in Fabricating Nanofibrous Drug Delivery Systems

Production and characterization of spray-dried theophylline powders prepared from fresh milk for potential use in paediatrics

In vitro Growth and Inhibition Studies of Monosodium Urate Monohydrate Crystals by Different Herbal Extracts

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