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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Hydroxypropylmethylcellulose in hydrophilic matrix dosage forms

Rajabi-Siahboomi, Ali Reza January 1993 (has links)
No description available.
2

Análise comparativa de perfis de dissolução in vitro e in silico de comprimidos de liberação modificada contendo metformina / Comparative analysis of dissolution profiles in vitro and in silico of modified release tablets containing metformin

Borge, Lucas Ferreira 23 October 2018 (has links)
A dissolução de um fármaco a partir de uma forma farmacêutica (FF) sólida oral é um pré-requisito para que o mesmo seja absorvido pelo organismo e cumpra seus efeitos terapêuticos. O ensaio de dissolução de medicamentos permite avaliar a quantidade de princípio ativo que é liberado a partir de sua FF, mimetizando in vitro o processo que ocorre no trato gastrointestinal (TGI). O DDDPlus® é o único programa de computador dedicado exclusivamente a simular ensaios de dissolução. O objetivo deste trabalho foi avaliar a capacidade do programa de computador DDDPlus® em fornecer perfis de dissolução in silico de comprimidos matriciais contendo metformina semelhantes aos perfis de dissolução in vitro e avaliar a possibilidade de substituir a comparação de perfis de dissolução in vitro de diferentes formulações de comprimidos matriciais contendo metformina pela comparação de perfis de dissolução in silico fornecidos pelo DDDPlus®.Para tanto, um planejamento estatístico foi realizado para obtenção de perfis de dissolução, variando a velocidade das pás e o uso do sinker. Os perfis de dissolução de 3 formulações teste (T1, T2 e T3) de comprimidos de liberação modificada por matriz polimérica contendo metformina foram comparadas pelos métodos de eficiência de dissolução (ED), tempo médio de dissolução (TMD), fator de diferença (f2) e fator de semelhança (f1). Os resultados indicaram o uso do sinker como fator determinante para a ED e TMD. Assim, o método que utilizava o sinker e a velocidade das pás de 50RPM foi utilizado para avaliar 4 produtos comercializados no Brasil. No DDDPlus® os ensaios de dissolução in vitro das formulações T1, T2 e T3 foram otimizadas para a obtenção das constantes de calibração (CC), as CC foram utilizadas para simular os ensaios de dissolução de T1, T2 e T3 em velocidades de 25 e 50RPM. Os perfis de dissolução simulados foram comparados aos perfis observados, resultando em valores de R2. Valores de R2 acima de 0,90 foram obtidos para todas as simulações realizadas utilizando CC de ensaios in vitro que utilizaram sinker, indicando o potencial do programa em auxiliar o desenvolvimento de novas formulações. Valores de R2 abaixo de 0,70 foram obtidos após a simulação de ensaios utilizando CC de ensaios in vitro que não utilizavam o sinker, indicando que o programa de computador não previu a adesão do comprimido ao fundo da cuba de dissolução durante o ensaio. Os perfis de dissolução simulados das formulações T1, T2 e T3 foram comparadas por f1 e f2 com os perfis de dissolução dos produtos do mercado. Tais comparações concluíram que o software não é indicado como substituto dos ensaios in vitro quando se almeja comparar perfis de dissolução. / Dissolution of a drug from an oral solid pharmaceutical form (FF) is a prerequisite for it to be absorbed by the body and to fulfill its therapeutic effects. in vitroDrug dissolution assay allows the amount of active principle released from a FF and mimics the in vivo the process that occurs in the gastrointestinal tract (TGI). DDDPlus® is the only computer program dedicated exclusively to simulating dissolution testing. The objective of this work was to evaluate the ability of DDDPlus® software to provide in silico dissolution profiles of matrix tablets containing metformin similar to in vitro dissolution profiles and to evaluate the possibility of replacing in vitro dissolution profiles comparison of different formulations of matrix tablets containing metformin for a comparison of in silico dissolution profiles provided by DDDPlus®. For this purpose, a statistical design was used, varying agitation speed and the use of sinker to obtain dissolution profiles for 3 test formulations (T1, T2 and T3) of polymer matrix-modified release tablets containing metformin. Dissolution profiles were compared by means of dissolution efficiency (ED), mean dissolution time (TMD), difference factor (f2) and similarity factor (f1). The results indicated the use of sinker as a determinant factor for ED and TMD. Thus, the method that used sinker and agitation speed of 50RPM was used to evaluate 4 products commercialized in Brazil. in vitro dissolution tests of the T1, T2 and T3 formulations were optimized using In DDDPlus® to obtain the calibration constants (CC), which were used to simulate dissolution profiles of T1, T2 and T3 at speeds of 25 and 50RPM. in silico dissolution profiles were compared to in vitro dissolution profiles, resulting in R2 values. R2 values above 0.90 were obtained for all simulations performed using CC from in vitro assays using sinker, indicating the potential of the program to assist the development of new formulations. R2 values below 0.70 were obtained after the simulation of assays using CC from in vitro assays that did not use the sinker, indicating that the computer program did not predict adhesion of the tablet to the bottom of the dissolution cell during the assay. The simulated dissolution profiles of the T1, T2 and T3 formulations were compared by f1 and f2 with the dissolution profiles of the market products. Such comparisons concluded that the software is not indicated as a substitute for in vitro assays when comparing dissolution profiles is desired.
3

Análise comparativa de perfis de dissolução in vitro e in silico de comprimidos de liberação modificada contendo metformina / Comparative analysis of dissolution profiles in vitro and in silico of modified release tablets containing metformin

Lucas Ferreira Borge 23 October 2018 (has links)
A dissolução de um fármaco a partir de uma forma farmacêutica (FF) sólida oral é um pré-requisito para que o mesmo seja absorvido pelo organismo e cumpra seus efeitos terapêuticos. O ensaio de dissolução de medicamentos permite avaliar a quantidade de princípio ativo que é liberado a partir de sua FF, mimetizando in vitro o processo que ocorre no trato gastrointestinal (TGI). O DDDPlus® é o único programa de computador dedicado exclusivamente a simular ensaios de dissolução. O objetivo deste trabalho foi avaliar a capacidade do programa de computador DDDPlus® em fornecer perfis de dissolução in silico de comprimidos matriciais contendo metformina semelhantes aos perfis de dissolução in vitro e avaliar a possibilidade de substituir a comparação de perfis de dissolução in vitro de diferentes formulações de comprimidos matriciais contendo metformina pela comparação de perfis de dissolução in silico fornecidos pelo DDDPlus®.Para tanto, um planejamento estatístico foi realizado para obtenção de perfis de dissolução, variando a velocidade das pás e o uso do sinker. Os perfis de dissolução de 3 formulações teste (T1, T2 e T3) de comprimidos de liberação modificada por matriz polimérica contendo metformina foram comparadas pelos métodos de eficiência de dissolução (ED), tempo médio de dissolução (TMD), fator de diferença (f2) e fator de semelhança (f1). Os resultados indicaram o uso do sinker como fator determinante para a ED e TMD. Assim, o método que utilizava o sinker e a velocidade das pás de 50RPM foi utilizado para avaliar 4 produtos comercializados no Brasil. No DDDPlus® os ensaios de dissolução in vitro das formulações T1, T2 e T3 foram otimizadas para a obtenção das constantes de calibração (CC), as CC foram utilizadas para simular os ensaios de dissolução de T1, T2 e T3 em velocidades de 25 e 50RPM. Os perfis de dissolução simulados foram comparados aos perfis observados, resultando em valores de R2. Valores de R2 acima de 0,90 foram obtidos para todas as simulações realizadas utilizando CC de ensaios in vitro que utilizaram sinker, indicando o potencial do programa em auxiliar o desenvolvimento de novas formulações. Valores de R2 abaixo de 0,70 foram obtidos após a simulação de ensaios utilizando CC de ensaios in vitro que não utilizavam o sinker, indicando que o programa de computador não previu a adesão do comprimido ao fundo da cuba de dissolução durante o ensaio. Os perfis de dissolução simulados das formulações T1, T2 e T3 foram comparadas por f1 e f2 com os perfis de dissolução dos produtos do mercado. Tais comparações concluíram que o software não é indicado como substituto dos ensaios in vitro quando se almeja comparar perfis de dissolução. / Dissolution of a drug from an oral solid pharmaceutical form (FF) is a prerequisite for it to be absorbed by the body and to fulfill its therapeutic effects. in vitroDrug dissolution assay allows the amount of active principle released from a FF and mimics the in vivo the process that occurs in the gastrointestinal tract (TGI). DDDPlus® is the only computer program dedicated exclusively to simulating dissolution testing. The objective of this work was to evaluate the ability of DDDPlus® software to provide in silico dissolution profiles of matrix tablets containing metformin similar to in vitro dissolution profiles and to evaluate the possibility of replacing in vitro dissolution profiles comparison of different formulations of matrix tablets containing metformin for a comparison of in silico dissolution profiles provided by DDDPlus®. For this purpose, a statistical design was used, varying agitation speed and the use of sinker to obtain dissolution profiles for 3 test formulations (T1, T2 and T3) of polymer matrix-modified release tablets containing metformin. Dissolution profiles were compared by means of dissolution efficiency (ED), mean dissolution time (TMD), difference factor (f2) and similarity factor (f1). The results indicated the use of sinker as a determinant factor for ED and TMD. Thus, the method that used sinker and agitation speed of 50RPM was used to evaluate 4 products commercialized in Brazil. in vitro dissolution tests of the T1, T2 and T3 formulations were optimized using In DDDPlus® to obtain the calibration constants (CC), which were used to simulate dissolution profiles of T1, T2 and T3 at speeds of 25 and 50RPM. in silico dissolution profiles were compared to in vitro dissolution profiles, resulting in R2 values. R2 values above 0.90 were obtained for all simulations performed using CC from in vitro assays using sinker, indicating the potential of the program to assist the development of new formulations. R2 values below 0.70 were obtained after the simulation of assays using CC from in vitro assays that did not use the sinker, indicating that the computer program did not predict adhesion of the tablet to the bottom of the dissolution cell during the assay. The simulated dissolution profiles of the T1, T2 and T3 formulations were compared by f1 and f2 with the dissolution profiles of the market products. Such comparisons concluded that the software is not indicated as a substitute for in vitro assays when comparing dissolution profiles is desired.
4

Recobrimento comestível com hidroxipropilmetilcelulose e agentes antiescurecimento em berinjela minimamente processada. / Hydroxypropyl methylcelullose based edible coating and antibrowning agentes in fresh cut eggplant.

Pinsetta Junior, José Sidnaldo 12 July 2018 (has links)
Submitted by José Sidnaldo Pinsetta Junior (j.pinsetta@gmail.com) on 2018-09-10T13:07:04Z No. of bitstreams: 1 Dissertação José Sidnaldo final - repositorio.pdf: 4492049 bytes, checksum: 4ab3eb4e73554043616e04c8821af820 (MD5) / Approved for entry into archive by Neli Silvia Pereira null (nelisps@fcav.unesp.br) on 2018-09-10T18:26:39Z (GMT) No. of bitstreams: 1 pinsettajunior_js_me_jabo.pdf: 4492049 bytes, checksum: 4ab3eb4e73554043616e04c8821af820 (MD5) / Made available in DSpace on 2018-09-10T18:26:39Z (GMT). No. of bitstreams: 1 pinsettajunior_js_me_jabo.pdf: 4492049 bytes, checksum: 4ab3eb4e73554043616e04c8821af820 (MD5) Previous issue date: 2018-07-12 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A berinjela é uma olerícola de grande importância em diversos países e seu consumo tem aumentado no Brasil devido às características nutricionais para a alimentação humana. No entanto, esse vegetal apresenta limitações de comercialização como produto minimamente processado devido ao rápido escurecimento enzimático após o corte. O objetivo deste trabalho foi estudar os efeitos do recobrimento comestível a base de hidroxipropilmetilcelulose (HPMC) combinado, ou não, com agentes antiescurecimento sobre a qualidade de berinjelas minimamente processadas (BMP). Foram utilizadas berinjelas da cv Nápoli higienizadas e processadas em cubos, com posterior aplicação os recobrimentos por aspersão. Na primeira etapa foram testadas três formulações de HPMC + Cera de Abelha (CA) nas concentrações de 20, 40 e 60%. No segundo experimento testou-se o efeito do HPMC associado ao ácido cítrico (0,5; 1 e 1,5 %) e no terceiro experimento, ao ácido ascórbico (0,5; 1 e 1,5 %). As BPM foram acondicionadas em embalagens de PET (Polietileno tereftalato) e armazenadas em expositores refrigerados a 5°C. As análises foram realizadas a cada 3 dias até 12 dias, determinando-se a perda acumulada de massa fresca, firmeza, índice de brancura, composição gasosa do interior da embalagem, determinação de acetaldeído e etanol, compostos fenólicos totais, atividade das enzimas polifenoloxidase (PPO), peroxidase (POD) e fenilalanina amônia-liase (PAL), e contagem microbiana (microrganismos aeróbios mesófilos, coliformes totais e E. coli). O recobrimento com HPMC+40% de cera de abelha reduziu a atividade de enzimas responsáveis pelo escurecimento e a adição de 0,5% de ácido cítrico ou 1% de ácido ascórbico ao recobrimento levou a uma menor síntese de compostos fenólicos e menor atividade enzimática. / The eggplant is a vegetable of great importance in many countries and it has an increasing consumption in Brazil thanks to nutritional benefits for human health. Nevertheless, it presents limitations to commercialization due to fast enzymatic browning after cutting. The aim of this Project was to study the effects of an edible coating Hydroxypropyl methylcellulose (HPMC) based in association, or not, with food aditives on the quality of fresh-cut eggplant (FCE). Eggplants cv. "Napoli" were sanitised and processed in cubes of 2,5 x 2,5 x 2,5 cm and later sprayed with the coatings. In the first step, three HPMC and Beewax (BW), 20, 40 and 60% emulsions were tested. In the second experiment, the effect of HPMC+40% BW associated with citric acid (0,5; 1 e 1,5 %) were assessed and in a third experiment, in association with ascorbic acid (0,5; 1 e 1,5 %). The FCE was packed in PET trays and stored at 5°C. Analysis were carried out each 3 days until 12 days. It was assessed the accumulated loss of fresh matter, firmness, whiteness index, atmosphere inside packaging, acetaldehyde and ethanol determination, total phenols, enzyme activity of polyphenol oxidase (PPO), peroxidase (POD), phenylalanine ammonia-lyase (PAL) and microbiology counting (total mesophilic aerobic count, total coliforms and E. coli). The coating with HPMC+40% BW reduced the activity of enzymes responsible for browning and the addition of 0,5% of citric acid or 1% of ascorbic acid to the coating led to a lower synthesis of phenolic compounds and to lower enzymatic activity. / FAPESP: 2016/23600-1
5

Development and formulation of an intranasal dosage form for cyclizine hydrochloride / Ntseliseng Selloane Bohloko

Bohloko, Ntseliseng Selloane January 2004 (has links)
A comprehensive review of the nasal route of administration, in particular the nasal drug delivery system has been presented. The physicochemical properties, mode of action and pharmacology of H1-receptor antagonists, in particular cyclizine HCl, have been highlighted. The techniques for the assessment of toxicity (in-vitro ciliary beat frequency (CBF) studies for human nasal explants and morphology studies of the rat nasal mucosa), synthesis of cyclizine lactate, solubility studies of both cyclizine HCI and cyclizine lactate, viscosity determination of the gel formulated and assessment of the deposition and distribution of the hydroxypropylmethyl cellulose (HPMC) dispersions within the human nasal cavity model were conducted. In this study, preliminary studies on the toxicity of the various formulation components (excipients and active ingredient) were carried out. Results from these studies indicated that for both the excipients and the drug, pH significantly affects the ciliary motility hence all ciliary beat frequency determinations were conducted at nasal pH. Furthermore, effects of the various concentrations (0.0625%(w/v), 0.125%(w/v), 0.25%(w/v), 0.5%(w/v) and l%(w/v)) of the excipients on ciliary motility were investigated. Transmission electron microscopy (TEM) studies proved useful in evaluating the integrity and changes in the surface morphology of the rat nasal mucosa post treatment with the various excipients (carboxymethyl cellulose, hydroxypropylmethyl cellulose, trimethyl chitosan 36.3% DQ, Carbopol P934 and polysorbate-80) at varying concentrations. Of the excipients investigated, hydroxypropylmethyl cellulose (HPMC) showed ciliofriendliness since there was no apparent ultra structural damage, although a slight decrease in ciliary beat frequency (CBF) was observed at the highest viscosity. Moreover, hydroxypropylmethyl cellulose (HPMC) is said to be a bioadhesive excipient, which would therefore confer its bioadhesive properties to the intranasal preparation to enhance the retention time between the absorbing mucosa and the drug and hence increase nasal drug absorption. This excipient was therefore selected as the ideal for use in the formulation of the intranasal preparation. The aqueous solubility of a drug plays an important role in nasal administration since it is required that the drug component be applied in a limited volume of about 200pl. To enhance the aqueous solubility of the sparingly water-soluble cyclizine HCl, a lactate salt was synthesised and characterised. This compound was found to be highly soluble in water. The intranasal preparation was therefore manufactured using the lactate form of cyclizine. A single blind study was conducted to determine and compare the pharmacokinetic parameters for both Valoid oral tablets containing 100mg cyclizine HCl (reference drug) and cyclizine lactate intranasal preparation 125mglml (study drug). The results obtained indicated a significant improvement in the bioavailability of cyclizine. For oral administration Cmax = 200.79ng/ml at tmax = 5.57h and for the intranasal preparation Cmax = 5354.22ng/ml at tmax = 1.59h. A 19.2-fold increase in drug bioavailability was observed after intranasal administration (AUCin = 122860.70ng/ml/h) compared with oral administration (AUCpo = 5943.48ng/ml/h). This enhanced bioavailability through nasal administration indicated that enhanced nasal drug absorption and hence increased bioavailability not only depends on the favourable anatomical and physiological characteristics of the nasal mucosa but possibly on the inherent physico-chemical characteristics of the drug molecule and the formulation components. Thus chemical modification of the sparingly water-soluble cyclizine HCl to the highly water-soluble cyclizine lactate facilitated the dissolution of more solute in a limited volume of solvent. This new feature therefore may have impacted positively to the transport of cyclizine across the nasal mucosa. Furthermore, the hydroxypropylmethyl cellulose (HPMC), component of the formulation, could have conferred its mucoadhesive properties to the preparation. Perhaps it increased the retention time of the dosage form within the nasal passages through bond formation with the nasal mucosa thereby increasing the contact time between the absorbing mucosa and the dosage form. This interaction between the mucoadhesive and the nasal mucosa may have resulted in the modification of tissue permeability (possibly transient opening of the tight junctions) and eventual increase in the drug penetration/absorption. / Thesis (Ph.D. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2004.
6

Study of polymer hydration and drug release: texture analysis and model evaluation

Li, Hongtao 23 July 2012 (has links)
Hydrophilic polymers in a swellable matrix tablet hydrate quickly to form a hydrogel layer on the exterior of the dosage once in contact with water or biologic fluid. The resultant hydrogel serves as a barrier to regulate water permeation into the matrix and drug diffusion from the preparation. It is therefore important to understand how the polymer is hydrated and what mechanism exists between hydrogel formation and drug dissolution from a swellable matrix tablet. In this thesis, a TA texture analyzer was utilized to monitor and characterize matrix swelling properties during dissolution process. Multiple regression models were employed to analyze the quantitative relationship between drug dissolution or hydrogel thickness and major formulation factors (polymer ratio, drug solubility). Modified release matrix tablets were prepared using four APIs with a range of aqueous solubility, i.e., acetaminophen (ACE), chlorpheniramine (CHL), ibuprofen (IBU), and pseudoephedrine hydrochloride (PSE). Two hydrophilic polymers, polyethylene oxide (PEO) and hydroxypropyl methylcellulose (HPMC) were selected and tested as primary matrix polymers for the formulations. It was found from the experiments that multiple regression model was capable of estimating drug dissolution for both PEO and HPMC matrix preparations. Based on major formulation factors the regression models provide satisfactory prediction of drug release, which could further aid in formulation development and optimization.
7

Development and formulation of an intranasal dosage form for cyclizine hydrochloride / Ntseliseng Selloane Bohloko

Bohloko, Ntseliseng Selloane January 2004 (has links)
A comprehensive review of the nasal route of administration, in particular the nasal drug delivery system has been presented. The physicochemical properties, mode of action and pharmacology of H1-receptor antagonists, in particular cyclizine HCl, have been highlighted. The techniques for the assessment of toxicity (in-vitro ciliary beat frequency (CBF) studies for human nasal explants and morphology studies of the rat nasal mucosa), synthesis of cyclizine lactate, solubility studies of both cyclizine HCI and cyclizine lactate, viscosity determination of the gel formulated and assessment of the deposition and distribution of the hydroxypropylmethyl cellulose (HPMC) dispersions within the human nasal cavity model were conducted. In this study, preliminary studies on the toxicity of the various formulation components (excipients and active ingredient) were carried out. Results from these studies indicated that for both the excipients and the drug, pH significantly affects the ciliary motility hence all ciliary beat frequency determinations were conducted at nasal pH. Furthermore, effects of the various concentrations (0.0625%(w/v), 0.125%(w/v), 0.25%(w/v), 0.5%(w/v) and l%(w/v)) of the excipients on ciliary motility were investigated. Transmission electron microscopy (TEM) studies proved useful in evaluating the integrity and changes in the surface morphology of the rat nasal mucosa post treatment with the various excipients (carboxymethyl cellulose, hydroxypropylmethyl cellulose, trimethyl chitosan 36.3% DQ, Carbopol P934 and polysorbate-80) at varying concentrations. Of the excipients investigated, hydroxypropylmethyl cellulose (HPMC) showed ciliofriendliness since there was no apparent ultra structural damage, although a slight decrease in ciliary beat frequency (CBF) was observed at the highest viscosity. Moreover, hydroxypropylmethyl cellulose (HPMC) is said to be a bioadhesive excipient, which would therefore confer its bioadhesive properties to the intranasal preparation to enhance the retention time between the absorbing mucosa and the drug and hence increase nasal drug absorption. This excipient was therefore selected as the ideal for use in the formulation of the intranasal preparation. The aqueous solubility of a drug plays an important role in nasal administration since it is required that the drug component be applied in a limited volume of about 200pl. To enhance the aqueous solubility of the sparingly water-soluble cyclizine HCl, a lactate salt was synthesised and characterised. This compound was found to be highly soluble in water. The intranasal preparation was therefore manufactured using the lactate form of cyclizine. A single blind study was conducted to determine and compare the pharmacokinetic parameters for both Valoid oral tablets containing 100mg cyclizine HCl (reference drug) and cyclizine lactate intranasal preparation 125mglml (study drug). The results obtained indicated a significant improvement in the bioavailability of cyclizine. For oral administration Cmax = 200.79ng/ml at tmax = 5.57h and for the intranasal preparation Cmax = 5354.22ng/ml at tmax = 1.59h. A 19.2-fold increase in drug bioavailability was observed after intranasal administration (AUCin = 122860.70ng/ml/h) compared with oral administration (AUCpo = 5943.48ng/ml/h). This enhanced bioavailability through nasal administration indicated that enhanced nasal drug absorption and hence increased bioavailability not only depends on the favourable anatomical and physiological characteristics of the nasal mucosa but possibly on the inherent physico-chemical characteristics of the drug molecule and the formulation components. Thus chemical modification of the sparingly water-soluble cyclizine HCl to the highly water-soluble cyclizine lactate facilitated the dissolution of more solute in a limited volume of solvent. This new feature therefore may have impacted positively to the transport of cyclizine across the nasal mucosa. Furthermore, the hydroxypropylmethyl cellulose (HPMC), component of the formulation, could have conferred its mucoadhesive properties to the preparation. Perhaps it increased the retention time of the dosage form within the nasal passages through bond formation with the nasal mucosa thereby increasing the contact time between the absorbing mucosa and the dosage form. This interaction between the mucoadhesive and the nasal mucosa may have resulted in the modification of tissue permeability (possibly transient opening of the tight junctions) and eventual increase in the drug penetration/absorption. / Thesis (Ph.D. (Pharmaceutics))--North-West University, Potchefstroom Campus, 2004.
8

Study of polymer hydration and drug release: texture analysis and model evaluation

Li, Hongtao 23 July 2012 (has links)
Hydrophilic polymers in a swellable matrix tablet hydrate quickly to form a hydrogel layer on the exterior of the dosage once in contact with water or biologic fluid. The resultant hydrogel serves as a barrier to regulate water permeation into the matrix and drug diffusion from the preparation. It is therefore important to understand how the polymer is hydrated and what mechanism exists between hydrogel formation and drug dissolution from a swellable matrix tablet. In this thesis, a TA texture analyzer was utilized to monitor and characterize matrix swelling properties during dissolution process. Multiple regression models were employed to analyze the quantitative relationship between drug dissolution or hydrogel thickness and major formulation factors (polymer ratio, drug solubility). Modified release matrix tablets were prepared using four APIs with a range of aqueous solubility, i.e., acetaminophen (ACE), chlorpheniramine (CHL), ibuprofen (IBU), and pseudoephedrine hydrochloride (PSE). Two hydrophilic polymers, polyethylene oxide (PEO) and hydroxypropyl methylcellulose (HPMC) were selected and tested as primary matrix polymers for the formulations. It was found from the experiments that multiple regression model was capable of estimating drug dissolution for both PEO and HPMC matrix preparations. Based on major formulation factors the regression models provide satisfactory prediction of drug release, which could further aid in formulation development and optimization.
9

Recobrimento comestível com hidroxipropilmetilcelulose e agentes antiescurecimento em berinjela minimamente processada / Hydroxypropyl methylcelullose based edible coating and antibrowning agentes in fresh cut eggplant

Pinsetta Junior, José Sidnaldo 12 July 2018 (has links)
Submitted by José Sidnaldo Pinsetta Junior (j.pinsetta@gmail.com) on 2018-07-25T00:08:38Z No. of bitstreams: 1 Dissertação José Sidnaldo Pinsetta Junior - versão final.pdf: 4463450 bytes, checksum: 1f7984d7f6b9905aa1c1ff1247d39508 (MD5) / Approved for entry into archive by Karina Gimenes Fernandes null (karinagi@fcav.unesp.br) on 2018-07-25T10:45:12Z (GMT) No. of bitstreams: 1 pinsettajunior_js_me_jabo.pdf: 4201809 bytes, checksum: b644c7389d5dfd07f09c8a0bc7398586 (MD5) / Made available in DSpace on 2018-07-25T10:45:12Z (GMT). No. of bitstreams: 1 pinsettajunior_js_me_jabo.pdf: 4201809 bytes, checksum: b644c7389d5dfd07f09c8a0bc7398586 (MD5) Previous issue date: 2018-07-12 / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / A berinjela é uma olerícola de grande importância em diversos países e seu consumo tem aumentado no Brasil devido às características nutricionais para a alimentação humana. No entanto, esse vegetal apresenta limitações de comercialização como produto minimamente processado devido ao rápido escurecimento enzimático após o corte. O objetivo deste trabalho foi estudar os efeitos do recobrimento comestível a base de hidroxipropilmetilcelulose (HPMC) combinado, ou não, com agentes antiescurecimento sobre a qualidade de berinjelas minimamente processadas (BMP). Foram utilizadas berinjelas da cv Nápoli higienizadas e processadas em cubos, com posterior aplicação os recobrimentos por aspersão. Na primeira etapa foram testadas três formulações de HPMC + Cera de Abelha (CA) nas concentrações de 20, 40 e 60%. No segundo experimento testou-se o efeito do HPMC associado ao ácido cítrico (0,5; 1 e 1,5 %) e no terceiro experimento, ao ácido ascórbico (0,5; 1 e 1,5 %). As BPM foram acondicionadas em embalagens de PET (Polietileno tereftalato) e armazenadas em expositores refrigerados a 5°C. As análises foram realizadas a cada 3 dias até 12 dias, determinando-se a perda acumulada de massa fresca, firmeza, índice de brancura, composição gasosa do interior da embalagem, determinação de acetaldeído e etanol, compostos fenólicos totais, atividade das enzimas polifenoloxidase (PPO), peroxidase (POD) e fenilalanina amônia-liase (PAL), e contagem microbiana (microrganismos aeróbios mesófilos, coliformes totais e E. coli). O recobrimento com HPMC+40% de cera de abelha reduziu a atividade de enzimas responsáveis pelo escurecimento e a adição de 0,5% de ácido cítrico ou 1% de ácido ascórbico ao recobrimento levou a uma menor síntese de compostos fenólicos e menor atividade enzimática. / The eggplant is a vegetable of great importance in many countries and it has an increasing consumption in Brazil thanks to nutritional benefits for human health. Nevertheless, it presents limitations to commercialization due to fast enzymatic browning after cutting. The aim of this Project was to study the effects of an edible coating Hydroxypropyl methylcellulose (HPMC) based in association, or not, with food aditives on the quality of fresh-cut eggplant (FCE). Eggplants cv. "Napoli" were sanitised and processed in cubes of 2,5 x 2,5 x 2,5 cm and later sprayed with the coatings. In the first step, three HPMC and Beewax (BW), 20, 40 and 60% emulsions were tested. In the second experiment, the effect of HPMC+40% BW associated with citric acid (0,5; 1 e 1,5 %) were assessed and in a third experiment, in association with ascorbic acid (0,5; 1 e 1,5 %). The FCE was packed in PET trays and stored at 5°C. Analysis were carried out each 3 days until 12 days. It was assessed the accumulated loss of fresh matter, firmness, whiteness index, atmosphere inside packaging, acetaldehyde and ethanol determination, total phenols, enzyme activity of polyphenol oxidase (PPO), peroxidase (POD), phenylalanine ammonia-lyase (PAL) and microbiology counting (total mesophilic aerobic count, total coliforms and E. coli). The coating with HPMC+40% BW reduced the activity of enzymes responsible for browning and the addition of 0,5% of citric acid or 1% of ascorbic acid to the coating led to a lower synthesis of phenolic compounds and to lower enzymatic activity. / FAPESP: 2016/23600-1
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Development of Extended Release Dextromethorphan Matrix Tablets

Bharaj, Satinder Singh 29 September 2005 (has links)
No description available.

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