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1.
AAPS PharmSciTech ; 22(7): 241, 2021 Sep 29.
Artigo em Inglês | MEDLINE | ID: mdl-34590171

RESUMO

The objective of this study was to stabilize the enteric property of bleached shellac by composite formation with ethyl cellulose. The composite film at the ratio of 9:1, 8:2, 7:3, 6:4, and 5:5 was prepared by the film casting method. The physicochemical properties were acid value, insoluble solid, water permeability coefficient, % polarity, mechanical property, FTIR, PXRD, DSC, % solubility in aqueous, and various pH (1.2 and 7.4). All the films were able to protect against the low pH and water. The total solubility at pH 7.4 was reported for the low ratio of ethyl cellulose (9:1 and 8:2). The stability of all films was then investigated for 180 days. The results demonstrated that the ethyl cellulose could stabilize the bleached shellac indicated by the low changes in acid value and insoluble solid. The higher ratio of ethyl cellulose contributed to the lower polymerization during storage. The results were due to the protection of the bleached shellac's active sites. The entanglement of ethyl cellulose caused interaction difficulties between active groups leading to stabilized bleached shellac. The proper ratio was 7:3 because of high solubility, and low polymerization. The findings demonstrated that the composite film could improve the enteric property of bleached shellac for a long period.


Assuntos
Resinas Vegetais , Permeabilidade , Polimerização , Solubilidade
2.
Asian J Pharm Sci ; 13(1): 34-43, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32104376

RESUMO

The aims of this study were to prepare and characterize hydroxypropyl methylcellulose (HPMC)/polycarbophil (PC) mucoadhesive blend films saturated with propranolol hydrochloride (PNL)-loaded nanoparticles to improve permeability of drugs that undergo first-pass metabolism. An ionic cross-linking method and film casting technique was used to prepare nanoparticles and mucoadhesive blend films, respectively. Increasing concentrations of PNL (70, 80, 90 mg/film) in HPMC/PC blend films containing PNL-loaded nanoparticles (PN-films) and HPMC/PC blend films containing PNL (80 mg/film) without nanoparticles (PP-films) were prepared to test swelling, mucoadhesiveness, release, permeation and physicochemical properties. Scanning electron microscope (SEM) images showed a partially smooth surface with a wrinkled occurrence and spherically shaped, well-dispersed nanoparticles on the surface of PN-films containing PNL 80 mg/film (PN-films-80). The size of the nanoparticles on the surface of PN-films-80 was around 100 nm, which was similar to the nanoparticle size observed using light scattering technique. The swelling index (SI) of all PN-films and PP-films increased greatly in the first period time (10-20 min) and reached swelling equilibrium at 20 min and 30 min, respectively. For the PN-films, the concentration of PNL influenced the mucoadhesive properties and tended to be higher when the amount of PNL increased. Immediate release of all blend film formulations was found in early time points (10-30 min). After 120 min, the release of PN-films-70 was lower than the other PN-films. Permeation studies using porcine buccal mucosa showed that inclusion of nanoparticles in the films increased the permeability of PNL compared to PP-films. Therefore, buccal administration of mucoadhesive blend films containing PNL-loaded nanoparticles could be a promising approach for drugs that undergo first-pass metabolism.

3.
Asian J Pharm Sci ; 13(5): 459-471, 2018 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32104420

RESUMO

The aim of this study was to elucidate the optimized fabrication factors influencing the formation and properties of shellac (SHL) nanofibers loaded with an antimicrobial monolaurin (ML). The main and interaction effects of formulation and process parameters including SHL content (35%-40% w/w), ML content (1%-3% w/w), applied voltage (9-27 kV) and flow rate (0.4-1.2 ml/h) on the characteristic of nanofibers were investigated through a total of 19 experiments based on a full factorial design with three replicated center points. As a result, the SHL content was the major parameter affecting fiber diameter. Another response result revealed that the SHL content would be also the most significant negative impact on amount of beads. An increase in the concentration of SHL leaded to a reduction in the amount of beads. From the results of characterization study, it was proved that ML might be entrapped between the chains of SHL during the electrospinning process exhibiting an excellent encapsulation. According to the response surface area, small (~488 nm) and beadless (~0.48) fibers were obtained with the SHL and ML contents of 37.5% and 1.1% w/w respectively, at the applied voltage of 18 kV and the flow rate of 0.8 ml/h. In addition, the results of the kill-kinetic studies showed that SHL nanofibers loaded with ML exhibited an excellent antibacterial activity against Staphylococcus aureus, while Escherichia coli was less affected due to the hydrophilic structure of the its outer membrane. ML also exerted an antifungal activity by reducing the number of Candida albicans colonies. Based on their structural and antimicrobial properties, SHL nanofibers containing ML could be potentially used as a medicated dressing for wound treatment.

4.
J Food Sci ; 82(12): 2915-2925, 2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29111590

RESUMO

The aim of this investigation was to develop the high moisture protective ability and stable pectin through the design of composite films based on varying shellac concentrations. A film casting method was applied to prepare a free film. The moisture protective properties and mechanical properties were investigated. The findings was the composite films exhibited the reductions in the hydrophilicity, water vapor permeability, and the moisture content compared with pectin films. The single and composite films were then study for their stability at 40 °C and 75% RH for 90 d. Among the concentrations of shellac, 50% (w/w) could improve stability in terms of moisture protection after 90 d of storage, whereas lower concentrations of shellac (10% to 40%) could not achieve this. However, the higher shellac content also contributed to weaker mechanical properties. The mechanical improvement and stability of composite films with the incorporation of plasticizers were further investigated. Polyethylene glycol 400 and diethyl phthalate at a concentration of 10% were used. The results indicated that both plasticizers could enhance the mechanical characteristics and had a slight effect on moisture protection. The stability of pectin in terms of moisture protective properties could, therefore, be modified through the fabrication of composite films with hydrophobic polymers, that is, shellac and the addition of proper plasticizers to enhance mechanical properties, which could offer wide applications for edible film in food, agro, and pharmaceutical industries. PRACTICAL APPLICATION: The composite film with 50% shellac could improve moisture protective properties of pectin film. Adding a plasticizer could build up the higher mechanical characteristics of composite film. Stability of pectin could be modified by fabrication of composite films with proper content of shellac and plasticizer.


Assuntos
Pectinas/química , Plastificantes/química , Resinas Vegetais/química , Permeabilidade , Polietilenoglicóis/química , Polímeros/química
5.
Chem Pharm Bull (Tokyo) ; 65(3): 284-294, 2017 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-27980251

RESUMO

The objectives of this study were to prepare the hydroxypropyl methylcellulose (HPMC)/polycarbophil (PC) mucoadhesive blend film and to investigate the main and interaction effect of HPMC and PC mixtures on the physicochemical and mechanical properties of blend films using a simplex lattice mixture design approach. The cubic and quadratic models were selected to analyze mucoadhesive properties in terms of work of adhesion and maximum detachment force, respectively. It was shown that HPMC/PC blend film had higher mucoadhesive properties than pure HPMC film. The suitable models for analyzing swelling index of blend films at various times were assessed. The puncture strength, % elongation and hydrophilicity of films were also examined. The pure HPMC film displayed more homogeneous and smoother structures compared with the blend film, as observed by scanning electron microscope and atomic force microscopy. Intermolecular hydrogen bonding between HPMC and PC was detected using Fourier transform infrared and X-ray diffraction. Therefore, the blend film shows high potential for use as a buccal delivery system.


Assuntos
Resinas Acrílicas/química , Derivados da Hipromelose/química , Resinas Acrílicas/síntese química , Interações Hidrofóbicas e Hidrofílicas , Derivados da Hipromelose/síntese química
6.
Eur J Pharm Sci ; 50(3-4): 303-11, 2013 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-23896171

RESUMO

The production of pharmaceutical nanoparticles by the spinning disk processing (SDP) technique has advantages in terms of its scalability and its capacity to produce readily tunable nanoparticles of narrow size distribution. In this study, we successfully developed a novel multiple stepwise SDP technique to develop aggregates of uniformly sized poly(methyl acrylates)-coated chitosan-diclofenac sodium nanocores (CS-PMA NPs) for colonic drug delivery. The processing conditions were optimized using the Box-Behnken design. SEM and TEM micrographs showed the optimized system to consist of 10 µm-sized agglomerates of CS-PMA NPs, the latter measuring 10nm in diameter. High drug entrapment of 88% was attained. Potential colon-targeted drug release from the CS-PMA NPs was demonstrated, with retardation of drug release in simulated gastrointestinal fluids and over 90% of the drug load released into simulated colonic fluid within 8 h. Drug uptake from CS-PMA NPs into Caco-2 cells was threefold higher than that from a control drug solution, with no apparent cytotoxicity observed at the NP doses administered. The collective data suggest that the SDP is a robust manufacturing method that can potentially be used to scale up the production of composite nanoparticulate colon-targeted drug delivery systems.


Assuntos
Anti-Inflamatórios não Esteroides/química , Quitosana/química , Diclofenaco/química , Nanopartículas/química , Ácidos Polimetacrílicos/química , Tecnologia Farmacêutica/métodos , Anti-Inflamatórios não Esteroides/administração & dosagem , Células CACO-2 , Colo/metabolismo , Diclofenaco/administração & dosagem , Humanos , Nanopartículas/administração & dosagem , Tamanho da Partícula
7.
Pharm Dev Technol ; 18(3): 686-93, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-22568768

RESUMO

The potential of using two natural polymers (chitosan and shellac) for the formation of nanoparticles by the process of ionic cross-linking to encapsulate bovine serum albumin, a model protein was investigated. Depending on the concentrations of chitosan, shellac and bovine serum albumin, three physical states - nanoparticle, aggregation, and solution could be observed as a result of the electrostatic force. The formation of nanoparticles was due to the balance between the repulsion force and attractive force while the imbalance between both forces resulted in the formation of aggregation and solution. The Fourier transform infrared spectroscopy and differential scanning calorimetry were applied to prove the nanoparticle formation. The particle size was characterized by the light scattering technique and was found in the range between 100 and 300 nm. The morphology of the particles, detected by transmission electron microscopy was spherical shape. The result showed that the zeta potential of the nanoparticles possessed positive charges. The concentrations of chitosan, shellac and bovine serum albumin had an influence on the physicochemical properties of the nanoparticles such as the particle size, the zeta potential, the encapsulation, the loading efficiencies and the cumulative release. Therefore, chitosan and shellac could be used to form nanoparticles for protein delivery by the ionic cross-linking method.


Assuntos
Quitosana/síntese química , Sistemas de Liberação de Medicamentos/métodos , Nanopartículas/química , Resinas Vegetais/síntese química , Soroalbumina Bovina/administração & dosagem , Soroalbumina Bovina/síntese química , Animais , Bovinos , Quitosana/administração & dosagem , Quitosana/farmacocinética , Nanopartículas/administração & dosagem , Tamanho da Partícula , Resinas Vegetais/administração & dosagem , Resinas Vegetais/farmacocinética , Soroalbumina Bovina/farmacocinética
8.
Eur J Pharm Biopharm ; 77(2): 320-6, 2011 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-21129484

RESUMO

Magnetic resonance imaging (MRI) was used to assess in situ swelling behaviors of spray-dried chitosan acetate (CSA) in 0.1N HCl, pH 6.8 and pH 5.0 Tris-HCl buffers. The in vitro drug releases from CSA matrix tablets containing the model drugs, diclofenac sodium and theophylline were investigated in all media using USP-4 apparatus. The effect of chitosan molecular weight, especially in pH 6.8 Tris-HCl, was also studied. In 0.1N HCl, the drug release from the matrix tablets was the lowest in relation to the highest swelling of CSA. The swelling kinetics in Tris-HCl buffers are Fickian diffusion according to their best fit to Higuchi's model as well as the drug release kinetics in all the media. The high swelling rate (k(s)(')) was found to delay the drug release rate (k'). The linear relationship between the swelling and fractions of drug release in Tris-HCl buffers was observed, indicating an important role of the swelling on controlling the drug release mechanism. Additionally, CSA of 200 and 800 kDa chitosan did not swell in pH 6.8 Tris-HCl but disintegrated into fractions, and the drug release from the matrix tablets was the highest.


Assuntos
Anti-Inflamatórios não Esteroides/farmacocinética , Broncodilatadores/farmacocinética , Quitosana/química , Diclofenaco/química , Diclofenaco/farmacocinética , Teofilina/farmacocinética , Anti-Inflamatórios não Esteroides/administração & dosagem , Anti-Inflamatórios não Esteroides/química , Broncodilatadores/administração & dosagem , Broncodilatadores/química , Humanos , Imageamento por Ressonância Magnética , Solubilidade , Comprimidos , Teofilina/administração & dosagem , Teofilina/química
9.
J Agric Food Chem ; 58(24): 12934-40, 2010 Dec 22.
Artigo em Inglês | MEDLINE | ID: mdl-21090749

RESUMO

The effects of molecular weight and concentration of plasticizer on physicochemical properties and stability of shellac films were investigated. Type of plasticizer was previously reported to have some effects on the stability of shellac films, and polyethylene glycol (PEG) was the plasticizer of choice for plasticizing shellac films. In this study, different molecular weights of PEG (200, 400 and 4000) were chosen at a concentration of 10% w/w of shellac films. Shellac in alcohol was prepared in a free film. The stability of shellac film was then performed at 75% RH, 40 °C for 3 months. The comparison was made between the film with and without plasticizer. Shellac films were then determined for acid value, insoluble solid, mechanical properties and water vapor permeability coefficient. It was reported that different molecular weights of PEG had some influence on physicochemical properties of the shellac films. Among different molecular weights of PEG, PEG 400 showed a suitable molecular weight that could protect the shellac chain at the carboxylic and hydroxyl groups. Therefore, the molecular weight of plasticizer played a crucial role for the protective ability at active sites. Further study was performed to investigate the effect of concentrations of PEG 400 on the stability. The results demonstrated that PEG 400 at a concentration of 10% (w/w) could prevent the polymerization process for only 4 months and a significant change of all parameters was then reported. However, a higher concentration, 20% (w/w) of PEG 400, could prolong the stability of shellac for 6 months of study. Therefore, the drawback of shellac as a natural polymer in pharmaceutical and food industries could be tackled by the appropriate size and concentration of plasticizer.


Assuntos
Polietilenoglicóis/química , Resinas Vegetais/química , Fenômenos Químicos , Peso Molecular , Permeabilidade , Plastificantes/química , Polimerização
10.
AAPS PharmSciTech ; 11(3): 1376-82, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20821174

RESUMO

Stability enhancement of protein-loaded chitosan microparticles under storage was investigated. Chitosan glutamate at 35 kDa and bovine serum albumin as model protein drug were used in this study. The chitosan microparticles were prepared by ionotropic gelation, and polyethylene glycol 200 (PEG 200) was applied after the formation of the particles. All chitosan microparticles were kept at 25°C for 28 days. A comparison was made between those preparations with PEG 200 and without PEG 200. The changes in the physicochemical properties of the microparticles such as size, zeta potential, pH, and percent loading capacity were investigated after 0, 3, 7, 14, and 28 days of storage. It was found that the stability decreased upon storage and the aggregation of microparticles could be observed for both preparations. The reduction in the zeta potential and the increase in the pH, size, and loading capacity were observed when they were kept at a longer period. The significant change of those preparations without PEG 200 was evident after 7 days of storage whereas those with PEG 200 underwent smaller changes with enhanced stability after 28 days of storage. Therefore, this investigation gave valuable information on the stability enhancement of the microparticles. Hence, enhanced stability of chitosan glutamate microparticles for the delivery of protein could be achieved by the application of PEG 200.


Assuntos
Cápsulas/síntese química , Quitosana/química , Portadores de Fármacos/síntese química , Composição de Medicamentos/métodos , Polietilenoglicóis/química , Soroalbumina Bovina/química , Difusão , Estabilidade de Medicamentos , Microesferas , Polímeros/química
11.
AAPS PharmSciTech ; 9(2): 571-6, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18459055

RESUMO

The purpose of this study was to prepare wax-incorporated pectin-based emulsion gel beads using a modified emulsion-gelation method. The waxes in pectin-olive oil mixtures containing a model drug, metronidazole, were hot-melted, homogenized and then extruded into calcium chloride solution. The beads formed were separated, washed with distilled water and dried for 12 h. The influence of various types and amounts of wax on floating and drug release behavior of emulsion gel beads of calcium pectinate was investigated. The drug-loaded gel beads were found to float on simulated gastric fluid if the sufficient amount of oil was used. Incorporation of wax into the emulsion gel beads affected the drug release. Water-soluble wax (i.e. polyethylene glycol) increased the drug release while other water-insoluble waxes (i.e. glyceryl monostearate, stearyl alcohol, carnauba wax, spermaceti wax and white wax) significantly retarded the drug release. Different waxes had a slight effect on the drug release. However, the increased amount of incorporated wax in the formulations significantly sustained the drug release while the beads remained floating. The results suggest that wax-incorporated emulsion gel beads could be used as a carrier for intragastric floating drug delivery.


Assuntos
Anti-Infecciosos/química , Cloreto de Cálcio/química , Portadores de Fármacos , Metronidazol/química , Pectinas/química , Ceras/química , Administração Oral , Anti-Infecciosos/administração & dosagem , Química Farmacêutica , Composição de Medicamentos , Emulsões , Ácidos Graxos/química , Álcoois Graxos/química , Suco Gástrico/química , Géis , Glicerídeos/química , Interações Hidrofóbicas e Hidrofílicas , Cinética , Metronidazol/administração & dosagem , Azeite de Oliva , Tamanho da Partícula , Óleos de Plantas/química , Polietilenoglicóis/química , Solubilidade , Propriedades de Superfície , Tecnologia Farmacêutica/métodos
12.
Eur J Pharm Biopharm ; 70(1): 335-44, 2008 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-18430548

RESUMO

The aim of this study was to improve enteric properties of shellac by the formation of succinate derivative through dry media reaction. Shellac and succinic anhydride were mixed and then co-ground by planetary ball mill. The ground mixture was then activated by heating for various times and washed for removal of excess succinic anhydride. The ground mixtures and the heat-activated mixtures were characterized by physical and chemical tests, including acid value, FTIR spectroscopy, (1)H NMR and (13)C NMR spectroscopy, thermal analysis and film properties. The results demonstrated that acid values of heat-activated shellac mixtures increased with the increase of annealing time, suggesting the presence of carboxylic acid moieties of succinate at shellac molecules. The results were in good agreement with the DSC thermograms. The melting peak of shellac disappeared after heating, while melting peak of succinic anhydride gradually decreased, suggesting the utilization of succinic anhydride for the esterification. The shellac succinate formation was also confirmed by (1)H NMR and (13)C NMR spectroscopies. Film prepared from shellac succinate showed improved solubility, especially at the pH of small intestine (5.8-6.7), as compared to native shellac. The shellac succinate film also demonstrated better mechanical property, in terms of increased flexibility. In conclusion, solid-state formation of shellac succinate ester, which had improved enteric properties, was easily accomplished under the concept of "green approach".


Assuntos
Resinas Vegetais/síntese química , Anidridos Succínicos/síntese química , Tecnologia Farmacêutica/métodos , Varredura Diferencial de Calorimetria , Química Farmacêutica , Formas de Dosagem , Concentração de Íons de Hidrogênio , Espectroscopia de Ressonância Magnética , Permeabilidade , Maleabilidade , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura de Transição , Volatilização , Água/química
13.
Eur J Pharm Biopharm ; 69(3): 1004-13, 2008 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-18362064

RESUMO

A new oral-controlled release matrix tablet based on shellac polymer was designed and developed, using metronidazole (MZ) as a model drug. The shellac-based matrix tablets were prepared by wet granulation using different amounts of shellac and lactose. The effect of annealing temperature and pH of medium on drug release from matrix tablets was investigated. The increased amount of shellac and increased annealing temperature significantly affected the physical properties (i.e., tablet hardness and tablet disintegration) and MZ release from the matrix tablets. The in-situ polymerization played a major role on the changes in shellac properties during annealing process. Though the shellac did not dissolve in acid medium, the MZ release in 0.1N HCl was faster than in pH 7.3 buffer, resulting from a higher solubility of MZ in acid medium. The modulation of MZ release kinetics from shellac-based matrix tablets could be accomplished by varying the amount of shellac or annealing temperature. The release kinetics was shifted from relaxation-controlled release to diffusion-controlled release when the amount of shellac or the annealing temperature was increased.


Assuntos
Composição de Medicamentos/métodos , Resinas Vegetais/química , Comprimidos , Algoritmos , Varredura Diferencial de Calorimetria , Preparações de Ação Retardada , Dureza , Concentração de Íons de Hidrogênio , Metronidazol/administração & dosagem , Metronidazol/química , Polímeros/síntese química , Solubilidade , Propriedades de Superfície , Temperatura
14.
Eur J Pharm Biopharm ; 69(1): 274-84, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-17962003

RESUMO

Pellets containing microcrystalline cellulose (MCC), a model drug (theophylline) and a range of levels of sodium alginate (i.e., 10-50% w/w) were prepared by extrusion/spheronization. Two types of sodium alginate were evaluated with and without the addition of either calcium acetate or calcium carbonate (0, 0.3, 3 and 10% w/w). The effects of amount and type of sodium alginate and calcium salts on pellet properties, e.g., size, shape, morphology and drug release behavior, were investigated. Most pellet formulations resulted in pellets of a sufficient quality with respect to size, size distribution and shape. The results showed that the amounts of sodium alginate and calcium salts influenced the size and shape of the obtained pellets. However, different types of sodium alginate and calcium salt responded to modifications to a different extent. A cavity was observed in the pellet structure, as seen in the scanning electron micrographs, resulting from the forces involved in the spheronization process. Most of pellet formulations released about 75-85% drug within 60 min. Incorporation of calcium salts in the pellet formulations altered the drug release, depending on the solubility of the calcium salts used. The drug release data showed a good fit into both Higuchi and Korsmeyer-Peppas equations.


Assuntos
Alginatos/química , Cálcio/química , Química Farmacêutica/métodos , Tecnologia Farmacêutica/métodos , Celulose/química , Composição de Medicamentos , Sistemas de Liberação de Medicamentos , Implantes de Medicamento , Elétrons , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Tamanho da Partícula , Sais/química , Solubilidade , Teofilina/administração & dosagem , Fatores de Tempo
15.
Eur J Pharm Biopharm ; 68(2): 253-9, 2008 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-17616377

RESUMO

A colonic drug delivery with a new concept based on a combination of time-, pH-, and enzyme-controlled system was developed. Spray-dried chitosan acetate (CSA) prepared from low molecular weight chitosan was characterized. A combination of CSA and hydroxypropyl methylcellulose (HPMC) was used as new compression-coats for 5-aminosalicylic acid (5-ASA) tablets. Factors affecting in-vitro drug release, i.e. % weight ratio of coating polymers, enzyme activity, pH of media, and excipients in core tablets, were evaluated. The tablets compression-coated with HPMC:CSA at 60:40 and 50:50% weight ratio providing lag times about 5-6h were able to pass through the stomach (stage I, 0.1N HCl) and small intestine (stage II, pH 6.8, Tris-HCl). The delayed release was time- and pH-controlled owing to the swelling with gradual dissolving of CSA and HPMC in 0.1N HCl and the less solubility of CSA at higher pH. After reaching the colon (stage III, pH 5.0, acetate buffer), the dissolution of CSA at low pH triggered the drug release over 90% within 14h. Furthermore, the degradation of CSA by beta-glucosidase in the colonic fluid enhanced the drug release while adding the disintegrant or the osmotic agent in the core tablets would affect the drug release.


Assuntos
Quitosana/administração & dosagem , Colo/metabolismo , Sistemas de Liberação de Medicamentos , Concentração de Íons de Hidrogênio , Metilcelulose/análogos & derivados , Varredura Diferencial de Calorimetria , Derivados da Hipromelose , Metilcelulose/química , Espectrofotometria Ultravioleta , Fatores de Tempo
16.
Eur J Pharm Biopharm ; 67(3): 690-8, 2007 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17576057

RESUMO

The objective of this study was to improve the properties of shellac by composite salts formation. The shellac samples were prepared in various salt forms by dissolving them with 2-amino-2-methyl-1-propanol (AMP) and ammonium hydroxide (AMN) at various ratios of AMP:AMN. The results demonstrated that aqueous solubility of the shellac salts was improved as the ratio of AMP:AMN increased. The absorbance ratio of the FTIR peaks assigned to CO stretching of carboxylate and carboxylic acid (ABS1556/ABS1716) was increased with the increase of the AMP fraction, suggesting that the solubility enhancement was due to more ionization of AMP salts. Moisture adsorption studies indicated that shellac salts were more hygroscopic as AMP content increased. After storage at 40 degrees C, 75% RH, the acid value and insoluble solid of AMP salts were relatively constant even after storage of up to 180 days, suggesting that AMP should protect polymerization. The ABS1556/ABS1716 values of the shellac salts were rapidly decreased after storage, especially for those consisting of a high percentage of AMN. Thus, AMP should bind much tighter at the carboxylate binding site as compared with AMN, resulting in more solubility and stability. In conclusion, optimized shellac properties could be easily accomplished by composite salts formation.


Assuntos
Resinas Vegetais/química , Comprimidos com Revestimento Entérico/química , Adsorção , Hidróxido de Amônia , Varredura Diferencial de Calorimetria , Fenômenos Químicos , Química Farmacêutica , Físico-Química , Análise Diferencial Térmica , Estabilidade de Medicamentos , Dureza , Hidróxidos/química , Indicadores e Reagentes , Propanolaminas/química , Sais , Solubilidade , Espectroscopia de Infravermelho com Transformada de Fourier
17.
J Agric Food Chem ; 55(3): 687-92, 2007 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-17263461

RESUMO

The aim of this study was to increase the stability of shellac because of the polymerization. A few approaches have been applied in this study. Shellac film was prepared in two salt forms, that is, ammonium and 2-methyl-2-amino 1-propanol salts, and a comparison was made with shellac film in free acid form. The other approach was by the application of plasticizers. These plasticizers were diethyl phathalate, triacetin, and polyethylene glycol 400 (PEG 400). Plasticized shellac and unplasticized shellac films in free acid form were then compared. All shellac films were kept in stability chamber at 40 degrees C, 75% RH for a period of 3 months. The studied parameters such as insoluble solid, acid value, mechanical properties, and water vapor permeability were detected every month. Analysis of variance (ANOVA) technique was used to analyze data. The applications of salt forms proved statistically significant (p < 0.01) to reduce the polymerization process whereas certain plasticizers could enhance the stability. PEG 400 was the only plasticizer that could show the increase in stability. The improvement of stability might be a result of the interference of a larger molecule of PEG 400 causing the difficulty in interaction among carboxyl or hydroxyl groups of shellac and the effect of lower loss of plasticizer.


Assuntos
Plastificantes/farmacologia , Resinas Vegetais/química , Sais/química , Fenômenos Químicos , Físico-Química , Estabilidade de Medicamentos , Polietilenoglicóis/farmacologia
18.
Eur J Pharm Biopharm ; 67(1): 227-35, 2007 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-17276664

RESUMO

The aim of this study was to investigate the possibility of producing alginate-based pellets by extrusion/spheronization and also to improve the formation of spherical alginate-based pellets by investigating the effect of additive in granulating liquid on characteristics and drug release from resulting pellets. Two types of sodium alginate (30%) were evaluated in combination with theophylline (20%), microcrystalline cellulose (50%) and different granulation liquids. The pellets were then prepared in a basket extruder, then spheronized and dried. The final products were characterized by morphological examination and drug release study. Different additives in the granulating liquid influenced the ability of the extruded mass to form pellets (the processability) with this technique. However, different sodium alginate types responded to shape modifications to a different extent. Long, dumbbell-shaped pellets were obtained with viscous granulating liquids. However, short, nearly spherical pellets were obtained with watery granulation liquid with calcium chloride that reduced the swelling ability of sodium alginate. Improvements in the pellet characteristics were also dependent on the sodium alginate type employed. Most of pellet formulations released about 75-85% drug within 60min and showed a good fit into both Higuchi and Korsmeyer-Peppas equations. Higher amount of 3% calcium chloride, as a granulating liquid, in the formulation showed higher mean dissolution time resulting from the cross-linking properties of calcium ions to the negative charges of alginate molecules.


Assuntos
Alginatos/química , Algoritmos , Cloreto de Cálcio/química , Química Farmacêutica , Composição de Medicamentos , Estabilidade de Medicamentos , Excipientes , Géis , Modelos Estatísticos , Tamanho da Partícula , Solubilidade
19.
Pharm Dev Technol ; 10(2): 189-96, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15926667

RESUMO

The objective of this study was to investigate the potential of chitosan salts as a carrier in the preparation of protein-loaded nanoparticles. Glutamic and aspartic acids were used to prepare chitosan salts of 35, 100, and 800 KDa. Nanoparticles of chitosan base, chitosan glutamate, and chitosan aspartate were produced by ionotropic gelation with sodium tripolyphosphate (TPP). Bovine serum albumin (BSA) was applied as a model protein at loading concentrations ranging from 0.2 to 2 mg/mL. The size of the nanoparticles, as measured by photon correlation spectroscopy, was in the range of 195 to 3450 nm, depending on type and molecular weight of chitosan. Nanoparticles prepared with higher molecular weight chitosan showed larger sizes. The encapsulation was controlled by the competition of BSA in forming ionic cross-linking with chitosan and by the entrapment of BSA during the gelation process. Higher BSA encapsulation efficiency (EE) was obtained for nanoparticles prepared with chitosan salts compared to those prepared with the base. The higher EE was a result of a higher degree of ionization, causing more active sites to interact with BSA. In addition, a higher and faster release of BSA from the nanoparticles into pH 7.4 buffer medium was observed for nanoparticles of the chitosan salts than was observed for nanoparticles of the chitosan base. The higher and faster release was attributed to higher EE and lower entrapment of BSA within the matrix of the nanoparticle during the gelation process. The influence of molecular weight on the property of nanoparticles exhibited different effects. The difference was a result of different organic acids used to prepare nanoparticles leading to the difference in polymer conformation and viscosity of organic acid solution. Therefore, this study showed that the characteristics of chitosan nanoparticles loaded with a protein drug could be readily modulated by changing the salt form or the molecular weight of the chitosan carrier.


Assuntos
Quitosana/química , Portadores de Fármacos/química , Excipientes/química , Soroalbumina Bovina/administração & dosagem , Animais , Cápsulas , Bovinos , Fenômenos Químicos , Físico-Química , Composição de Medicamentos , Peso Molecular , Tamanho da Partícula , Soroalbumina Bovina/química , Viscosidade
20.
Pharm Dev Technol ; 10(1): 41-6, 2005.
Artigo em Inglês | MEDLINE | ID: mdl-15776812

RESUMO

The objective of this study was to investigate the effect of alkali treatment on properties of shellac. The native shellac was treated with sodium hydroxide for 15, 30, and 60 min to obtain hydrolyzed shellac. All types of shellac, namely native and hydrolyzed shellac at various times of treatment, were then prepared in films as free acid and ammonium salt forms by using ethanol and ammonium hydroxide solution, respectively. The results showed that alkali treatment caused an increase in acid value and a decrease in ester value. This is due to higher free carboxylic and hydroxyl groups caused by ester bond breaking. The longer the alkali treatment the higher impact of bond breaking, therefore, causing an increase in acid value, solubility at pH 7, strain, a decrease in ester value, water vapor permeability coefficient, and stress. The films were then kept at 40 degrees C, 75% RH for a period of three months. The aging effect led to an esterification of free carboxylic and hydroxyl groups, resulting in the significant change of acid value, ester value, and insoluble solid for both native and hydrolyzed shellac films in acid form. On the other hand, all types of shellac films in ammonium salt form exhibited a reasonable stability in physicochemical and mechanical properties as all films were protected from the esterification due to the formation of ammonium salt at the carboxylic binding site. It could be concluded that alkali treatment could produce hydrolyzed shellac with higher solubility in the intestine, the stability was yet in dilemma unless the shellac was in an ammonium salt form. The result obtained could, thus, provide a guideline in the use of shellac.


Assuntos
Álcalis/química , Resinas Vegetais/química , Álcalis/análise , Estabilidade de Medicamentos , Hidrólise , Resinas Vegetais/análise
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