Examinando por Autor "Alvarado, Angel T."

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  • Miniatura
    PublicaciónAcceso abierto
    “Bioadsorption of silver ions by calcareous chitin, chitin and chitosan“
    (Academic Association of Pharmaceutical Sciences from Antofagasta (ASOCIFA), 2023-01-02) Jáuregui-Nongrados, John; Alvarado, Angel T.; Mucha, Miguel; Muñoz, Ana M.; Chávez, Haydee; Molina-Cabrera, Aura; Cuba-García, Pompeyo A.; Melgar-Merino, Elizabeth J.; Bolarte-Arteaga, Mario; Mori-Castro, Jaime A.
    “Context: Calcareous chitin, chitin, chitosan, and their modifications are used as bioadsorbents of metals and dyes that cause environmental pollution, endocrine disruption, and human diseases. Aims: To evaluate the selective bioadsorption of silver ions (Ag+ ) by calcareous chitin, chitin, and chitosan. Methods: Experimental and prospective study. The presence of functional groups of the bioadsorbents was identified by Fourier-transformed infrared spectroscopy (FT-IR), 1H-NMR spectroscopy and scanning electron microscopy (SEM). The Langmuir, Freundlich, and Elovich models were applied to describe the adsorption capacity of bioadsorbents according to granule size (20-40, 40-60, 60-80 meshes) and temperature (10, 20, and 30°C). Results: The FT-IR spectrum of calcareous chitin indicates the presence of carbonate (CO3 = 1420 cm-1 ), amide III (1313 cm-1 ), –OH groups (3441.90 cm-1 ), and pyranose structure (952.83 cm-1 ); chitin has –OH groups (3441.90 cm-1 ), NH (3268 cm-1 ), amide I (1654 cm-1 ) and II (1559 cm-1 ); chitosan has –OH groups (3419.90 cm-1 ), –NH (3200 cm-1 ), amide I (1712.18 cm-1 ), –NH2 (1654.46 cm-1 ), amide III (1317.11 cm-1 ) and pyranose structure (1070.12 cm-1 and 1031 cm-1 ). The Langmuir model indicates greater bioadsorption of Ag+ ions at smaller particle sizes (60-80 = 0.25-0.18 mm) and at a temperature of 20-30°C. Conclusions: The bioadsorption of silver ions (Ag+ ) by chitosan is greater with respect to calcareous chitin and chitin; the Langmuir model fits for the Ag+ isotherm and suggests that the process is controlled by physisorption. “
  • Miniatura
    PublicaciónAcceso abierto
    “Review: Application of Bioequivalence Testing of Medicines in Peru“
    (Dissolution Technologies Inc, 2022-11) Alvarado, Angel T.; Gray, Vivian; Muñoz, Ana María; Saravia, María; Bendezú, María R.; Chávez, Haydee; García, Jorge A.; Ybañez-Julca, Roberto; Chonn-Chang, Andres; Basurto, Patricia; Pineda-Pérez, Mario; Salazar, Alberto
    “This is a review of the current status of drug bioequivalence studies in Peru. A bibliographic search was conducted in PubMed (Medline database) for bioequivalence studies in Peru. Generic drugs constitute the basis of pharmacological requests in health care systems in Latin American countries. Peru has enacted laws and regulations that require bioequivalence studies of high health risk drugs and exemptions, based on international legislation, to be conducted in research centers accredited by the authority of Health. There is a list of 19 drugs that must demonstrate their therapeutic equivalence through in vivo or in vitro studies, of which 13 have shown bioequivalence in vivo, and 8 of those have shown bioequivalence in vitro. There is a challenge for health authorities to enforce the current legislation and an even greater challenge for pharmaceutical laboratories to demonstrate bioequivalence of multi-source drugs with the reference drug. “