Banca de DEFESA: JANIELE MAYARA FERREIRA DE ALMEIDA
Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.DISCENTE : JANIELE MAYARA FERREIRA DE ALMEIDA
DATA : 28/06/2019
HORA: 09:00
LOCAL: Auditório do NUPPRAR
TÍTULO:
SYNTHESIS AND CHARACTERIZATION OF SILICA NANOPARTICLES OBTAINED FROM EXPANDED PERLITE FOR APPLICATION IN THE PH-RESPONSIVE RELEASE OF DRUGS
PALAVRAS-CHAVES:
Isoniazid; topiramate; drug delivery system; pH-responsive system; nanoparticles of silica; expanded perlite; GC-MS
PÁGINAS: 151
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Química Analítica
ESPECIALIDADE: Instrumentação Analítica
RESUMO:
Drug delivery systems whose performance depends on external conditions such as pH are called pH-dependent or pH-responsive. They are materials capable of promoting prolonged and / or specific drug delivery. Silica nanoparticles (NPS) are excellent materials for application as pH-responsive systems, since their surface is abundant in silanols (Si-OH) groups, which are highly sensitive to variations in pH. Isoniazid (INH) is one of the first-line tuberculostatics for long treatment periods. Part of INH degrades in very acidic media such as stomach pH, impairing the treatment of tuberculosis and requiring high daily doses to maintain the therapeutic effect. Topiramate (TPM) is a potent antiepileptic, used in high daily dosages since it has low bioavailability. In this context, NPS were used as inorganic matrices for the in vitro release of TPM and INH. The synthesis of NPS was made using a natural source of silica as a precursor (the expanded perlite, a natural, low cost and abundant aluminosilicate), by a fast, simple and without many apparatus. The synthesis parameters by Stöber method (sol-gel process), were varied obtaining particles of different sizes and size distribution (monomodal and bimodal). NPS were characterized by XRD, FTIR, SEM, DLS and zeta potential. They presented amorphous structure and spherical morphology. A methodology for the detection and quantification of TPM by GC-MS was developed and validated (following ANVISA, RDC 166 of 2017), replacing the standard technique of HPLC-MS, since the TPM can not be detected by spectrophotometric techniques. The drugs were incorporated in the NPS under optimized conditions by experimental design (factorial, 2n) by different methods: INH by adsorption and melt-loading TPM. The incorporation of the TPM brought a new methodology for the preparation of carriers using a thermogravimetric (TG) system of great temperature control in a thermobalance. The drug release study was done using dissolution media simulating the gastrointestinal pH: pH 1.2 (stomach), pH 6.8 and 7.4 (intestine). The duration of the assay followed the estimated time of gastrointestinal transit that an oral solid pharmaceutical form faces upon ingestion. The release profile showed that NPS presented a pH-responsive surface (greater release at pH 7.4) and with prolonged release of the drugs (8 hours for INH and 5 hours for TPM). The kinetic study evaluated the zero order, first order and Higuchi models for drug release in NPS, and the zero order model was the one that presented the best fit, confirming the aforementioned release profile. This greater release in intestinal pH guarantees a lower degradability in the acidic environment (stomach), greater absorption and efficiency of the drugs.
MEMBROS DA BANCA:
Externo à Instituição - JOÃO AUGUSTO OSHIRO JUNIOR - UEPB
Externo à Instituição - BOLIVAR PONCIANO GOULART DE LIMA DAMASCENO - UEPB
Externa ao Programa - 2569445 - LOURENA MAFRA VERISSIMO
Interna - 2203888 - MARCIA RODRIGUES PEREIRA
Presidente - 1412709 - NEDJA SUELY FERNANDES
Interna - 1308577 - SIBELE BERENICE CASTELLA PERGHER