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1.
IUBMB Life ; 67(12): 966-70, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26545561

RESUMO

Low-molecular-mass trypsin inhibitors from Arabidopsis thaliana, Brassica napus var. oleifera, and Sinapis alba L. (ATTI, RTI, and MTI, respectively) display more than 69% amino acid sequence identity. Among others, the amino acid sequence Cys-Ala-Pro-Arg-Ile building up the inhibitor reactive site, and the eight Cys residues forming four disulfide bridges are conserved. However, the disulfide bridge connectivity of RTI and MTI (C1-C3, C2-C4, C5-C6, and C7-C8) is different from that of ATTI Cys (C1-C8, C2-C5, C3-C6, and C4-C7). Despite the different disulfide bridge connectivity, the reactive site loop of ATTI, RTI, and MTI is solvent exposed permitting trypsin recognition. Structural considerations here reported suggest that proteins showing high amino acid sequence identity and common functional properties could display different three-dimensional structures. This may reflect high inhibitor plasticity in relation to plant-pathogen interactions, plant tissue development as well as the different redox potential of cell compartments.


Assuntos
Brassicaceae/química , Dobramento de Proteína , Inibidores da Tripsina/química , Sequência de Aminoácidos , Dissulfetos/química , Modelos Moleculares , Dados de Sequência Molecular , Proteínas de Plantas/química , Homologia Estrutural de Proteína , Inibidores da Tripsina/metabolismo , Tripsinogênio/química , Tripsinogênio/genética , Tripsinogênio/metabolismo
2.
J Liposome Res ; 20(4): 277-85, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-19961302

RESUMO

The present article describes a comparative study of the performances of liposomes and ethosomes as specialized delivery systems for distamycin A (DA) and two of its derivatives. Liposomes and ethosomes were prepared by classical methods, extruded through polycarbonate filters, and characterized in terms of dimensions, morphology, and encapsulation efficiency. It was found that DA was associated with vesicles (either liposomes or ethosomes) by around 16.0%, while both derivatives of DA showed a percentage of association around 80% in the case of liposomes and around 50% in the case of ethosomes. In vitro antiproliferative activity experiments performed on cultured human and mouse leukemic cells demonstrated that vesicles were able to increase the activity of both derivatives of DA. In addition, it was demonstrated that the aging of both liposomes- and ethosomes-associated distamycin suspensions did not heavily influence the vesicle size, while all samples showed a relevant drug leakage with time. Moreover, according to the different physicochemical characteristics of DA and its derivatives (i.e., log P), vesicle-associated DA showed the highest loss of drug with respect to both its derivatives. In conclusion, the enhancement of drug activity expressed by these specialized delivery systems-associated DD could be interesting to obtain an efficient therapeutic effect aimed at reducing or minimizing toxic effects occurring with distamycins administration.


Assuntos
Antibacterianos , Distamicinas , Portadores de Fármacos , Etanol/química , Lipossomos/química , Lipossomos/metabolismo , Animais , Antibacterianos/administração & dosagem , Antibacterianos/química , Antibacterianos/metabolismo , Materiais Biocompatíveis/química , Materiais Biocompatíveis/metabolismo , Linhagem Celular , Distamicinas/administração & dosagem , Distamicinas/química , Distamicinas/metabolismo , Portadores de Fármacos/química , Portadores de Fármacos/metabolismo , Estabilidade de Medicamentos , Humanos , Lipossomos/ultraestrutura , Teste de Materiais , Camundongos , Estrutura Molecular , Tamanho da Partícula , Fatores de Tempo
3.
Eur J Pharm Biopharm ; 66(1): 11-20, 2007 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17085025

RESUMO

The aim of this work is to safely transport bioadhesive microspheres loaded with DNA to intestine and to test their bioadhesive properties. Poly(vinyl alcohol) (PVA) microspheres were prepared by dispersion reticulation with glutaraldehyde and further aminated. These microspheres were firstly loaded with plasmid DNA by electrostatic interactions and then entrapped in cellulose acetate butyrate (CAB) microcapsules for gastric protection. The entrapped PVA microspheres do not have enough force by swelling to produce the rupture of CAB shell, therefore the resistance of microcapsules was weakened by incorporating different amount of the pH/thermosensitive polymer (SP) based on poly(N-isopropylacrylamide-co-methyl methacrylate-co-methacrylic acid) (NIPAAm-co-MM-co-MA). This polymer is insoluble in gastric juice at pH 1.2 and 37 degrees C, but quickly solubilized in intestinal fluids (pH 6.8 and pH 7.4). Therefore, DNA loaded PVA microspheres were not expelled in acidic media but were almost entirely discharged in small intestine or colon. The integrity of DNA after entrapment was tested by agarose gel electrophoresis indicating that no DNA degradation occurs during encapsulation. The percentage of adhered microspheres on the mucus surface of everted intestinal tissue was 65+/-18% for aminated PVA microspheres without DNA and almost 50+/-15% for those loaded with DNA. Non-aminated PVA microspheres display the lowest adhesive properties (33+/-12%). In conclusion DNA loaded microspheres were progressively discharged in intestine. The integrity of DNA was not modified after entrapment and release, as proved by agarose gel electrophoresis. Both loaded and un-loaded aminated microspheres display good bioadhesive properties.


Assuntos
Celulose/análogos & derivados , DNA/administração & dosagem , Microesferas , Polímeros/química , Álcool de Polivinil/administração & dosagem , Administração Oral , Aminação , Animais , Celulose/química , DNA/genética , DNA/farmacocinética , Composição de Medicamentos , Sistemas de Liberação de Medicamentos/métodos , Avaliação Pré-Clínica de Medicamentos/métodos , Estabilidade de Medicamentos , Eletroforese em Gel de Ágar , Concentração de Íons de Hidrogênio , Mucosa Intestinal/efeitos dos fármacos , Mucosa Intestinal/metabolismo , Masculino , Plasmídeos/genética , Álcool de Polivinil/química , Álcool de Polivinil/farmacocinética , Ratos , Solubilidade , Propriedades de Superfície , Temperatura
4.
Int J Pharm ; 339(1-2): 52-60, 2007 Jul 18.
Artigo em Inglês | MEDLINE | ID: mdl-17395411

RESUMO

In the present study, the preparation, characterization and activity of non-phospholipid vesicles (NPV) containing three aminoacid-based molecules were described. As model compounds trypsin, bovine basic pancreatic inhibitor and polylysine rich peptides derived from the herpes simplex virus type 1 (HSV-1) glycoprotein B were employed. NPV were chosen as alternative to liposomes for the possible administration of aminoacid based molecules via mucous membrane (nasal or vaginal) routes. NPV containing the indicated model drugs have shown to be more stable in term of size with respect to liposomes encapsulating the same model drugs previously produced by our group [Cortesi, R. Argnani, R., Esposito, E., Dalpiaz, A. Scatturin, A., Bortolotti, F., Lufino, M., Guerrini, R., Incorvaia, C., Menegatti, E., Manservigi, R., 2006. Cationic liposomes as potential carriers for ocular administration of peptides with antiherpetic activity. Int. J. Pharm. 317, 90-100]. In addition our study indicates that the produced NPV (i) are able to encapsulate the model drugs over 49%, (ii) are characterized by dimensions compatible with applications on the mucous membrane, (iii) remain stable in size for at least 3 months and (iv) can release the model drug (after a slight lag time) in a controlled fashion as compared to that of the corresponding free solution.


Assuntos
Portadores de Fármacos , Peptídeos/administração & dosagem , Proteínas/administração & dosagem , Sequência de Aminoácidos , Aprotinina/administração & dosagem , Proliferação de Células/efeitos dos fármacos , Portadores de Fármacos/química , Estabilidade de Medicamentos , Dados de Sequência Molecular , Solubilidade , Tripsina/administração & dosagem , Proteínas do Envelope Viral/administração & dosagem
5.
FEBS J ; 272(24): 6287-96, 2005 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-16336266

RESUMO

Human serum albumin (HSA), the most prominent protein in plasma, is best known for its exceptional capacity to bind ligands (e.g. heme and drugs). Here, binding of the anti-HIV drugs abacavir, atazanavir, didanosine, efavirenz, emtricitabine, lamivudine, nelfinavir, nevirapine, ritonavir, saquinavir, stavudine, and zidovudine to HSA and ferric heme-HSA is reported. Ferric heme binding to HSA in the absence and presence of anti-HIV drugs was also investigated. The association equilibrium constant and second-order rate constant for the binding of anti-HIV drugs to Sudlow's site I of ferric heme-HSA are lower by one order of magnitude than those for the binding of anti-HIV drugs to HSA. Accordingly, the association equilibrium constant and the second-order rate constant for heme binding to HSA are decreased by one order of magnitude in the presence of anti-HIV drugs. In contrast, the first-order rate constant for ligand dissociation from HSA is insensitive to anti-HIV drugs and ferric heme. These findings represent clear-cut evidence for the allosteric inhibition of anti-HIV drug binding to HSA by the heme. In turn, anti-HIV drugs allosterically impair heme binding to HSA. Therefore, Sudlow's site I and the heme cleft must be functionally linked.


Assuntos
Regulação Alostérica , Fármacos Anti-HIV/química , Heme/química , Albumina Sérica/química , Sítios de Ligação , Heme/farmacologia , Humanos , Cinética , Ligação Proteica
6.
Biomaterials ; 26(20): 4337-47, 2005 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-15683658

RESUMO

Sulfopropylated dextran microspheres (SP-Ms), (Dm = 80 microm) loaded with a water soluble drug (Tetracycline HCl), were included in cellulose acetate butyrate (CAB) microcapsules. Spherical CAB microcapsules were obtained by oil in water (o/w) solvent evaporation method in the presence of an inert solvent as cyclohexane (CyH) or n-hexane (N-Hex), and different excipients (Phospholipon, Tween, Span, Eudragit RS 100). Chloroform was found to be the best solvent for the preparation of the microcapsules. Also, the sphericity as well as the porosity of the microcapsules was controlled by the presence of an inert solvent. The final concentration of the drug in CAB microparticles was up to 25% (w/w). The key factors for the successful preparation were also the viscosity of the polymer, while the wettability of the resulted microcapsules, the temperature of the preparation, and the porosity have modulated the release of the drug. The higher is the amount of encapsulated microspheres the thinner is the CAB wall between the compartments created by their incorporation. When these microspheres come in contact with the release medium, the pressure created by their swelling breaks the polymer film and the drug starts to be released. The more drug is released in phosphate buffer the higher is the swelling degree of the encapsulated ion exchange resins and the force created by their supplementary swelling will break the more resistants walls. In this way a self-propelled drug release is achieved, until almost all drug was eliberated.


Assuntos
Cápsulas/química , Celulose/análogos & derivados , Celulose/química , Preparações de Ação Retardada/química , Dextranos/química , Resinas de Troca Iônica/química , Tetraciclina/administração & dosagem , Tetraciclina/química , Antibacterianos/administração & dosagem , Antibacterianos/química , Materiais Biomiméticos/química , Difusão , Suco Gástrico/química , Conteúdo Gastrointestinal/química , Tamanho da Partícula , Veículos Farmacêuticos/química
7.
Int J Pharm ; 288(1): 35-49, 2005 Jan 06.
Artigo em Inglês | MEDLINE | ID: mdl-15607256

RESUMO

The present paper describes the production of biodegradable microparticles using different hyaluronan polymers, such as native hyaluronan, the esterified derivative of hyaluronan Hyaff 11p50 (where 50% of the carboxy groups of hyaluronic acid are esterified with benzyl alcohol) and the autocross-linked polymer (ACP) internally esterified derivative of hyaluronan, by solvent evaporation and spray-drying methods. As model drugs cromolyn sodium salt, metronidazole and prednisolone hemisuccinate sodium salt were employed. The influence of polymer and preparation procedure has been evaluated on microparticle characteristics (i.e. morphology and encapsulation yield) and on the drug release profiles. The use of solvent evaporation method, a polymeric matrix constituted of Hyaff 11p50 3% (w/v), a dispersing phase constituted of 80 g of mineral oil (w/o ratio: 0.1), Span 85 0.1% (w/w) as stabilizer, and a stirring speed of 700 rpm resulted in the production of microspheres characterized by spherical shape, absence of aggregates, a mean diameter of 6.4 microm and a recovery of 90% (w/w). The production of drug containing microspheres led to an increase of mean diameter of microspheres and to high encapsulation yields. Moreover in vitro models have demonstrated that in all cases drugs were released from Hyaff 11p50 microspheres in a controlled fashion. Finally mathematical analysis of the drug release modalities has evidenced that drug release from Hyaff 11p50 microspheres is more consistent with kinetics of the diffusion rather than of the dissolution type.


Assuntos
Sistemas de Liberação de Medicamentos/métodos , Ácido Hialurônico/química , Microesferas , Ácido Hialurônico/administração & dosagem , Ácido Hialurônico/farmacocinética
8.
Macromol Biosci ; 5(10): 955-64, 2005 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-16211551

RESUMO

Despite the large number of publications and patents concerning pH/thermoresponsive polymers, few data are available concerning the preparation of thermoresponsive cross-linked microspheres from preformed polymers. Therefore, N-isopropylacrylamide-co-acrylamide-co-(2-hydroxyethyl acrylate) copolymers were obtained as a new thermoresponsive material with a lower critical solution temperature (LCST) around 36 degrees C, in phosphate buffer at pH 7.4, and with a cross-linkable OH group in their structure. The LCST value was determined both by UV spectroscopy and microcalorimetric analysis. These copolymers were solubilised in acidified aqueous solution below their LCST, dispersed in mineral oil, and transformed into stable microspheres by cross-linking with glutaraldehyde. The thermoresponsive microspheres were characterised by optical and scanning electron microscopy, degree of swelling, and water retention. The pore dimensions of the microspheres and the retention volumes of some drugs and typical compounds were evaluated at different temperatures by liquid chromatography. Indomethacin, as a model drug, was included in the microspheres by the solvent evaporation method. Finally, the influence of temperature and of temperature cycling on drug release was investigated.


Assuntos
Acrilamidas/química , Acrilamidas/síntese química , Acrilatos/química , Acrilatos/síntese química , Portadores de Fármacos/química , Portadores de Fármacos/síntese química , Microesferas , Polímeros/química , Anti-Inflamatórios não Esteroides/metabolismo , Calorimetria , Cromatografia Líquida , Preparações de Ação Retardada/metabolismo , Concentração de Íons de Hidrogênio , Indometacina/metabolismo , Cinética , Microscopia Eletrônica de Varredura , Tamanho da Partícula , Temperatura , Água/química
9.
J Pharm Pharmacol ; 57(9): 1169-76, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16105237

RESUMO

We have investigated the influence of charge and lipid concentration on the in-vivo percutaneous absorption of a model compound, methyl nicotinate (MN), from liposomal vesicles. MN-loaded liposomes were produced by the reverse-phase evaporation method (REV) using different concentrations of phosphatidyl choline (PC), in association with surfactants such as dioctadecyl dimethyl ammonium bromide (DDAB18) and dicetyl phosphate (DCP), which impart a positive or negative charge to the systems, respectively. The liposomal suspensions were then processed to hydrogels and used to study in-vivo the MN permeation profile. MN was chosen as the model compound since it was capable of causing cutaneous erythema, the intensity and duration of which was proportional to the amount entering the living epidermis over time. The extent of the erythema was monitored by reflectance spectrophotometry, a non-invasive technique. In-vivo findings showed an interesting MN delayed release, which was proportional to the amount of phospholipids in each liposomal formulation. Furthermore, it could be noted that the erythematous effect was more prolonged when MN was delivered from neutral or negatively-charged liposomal forms.


Assuntos
Lipídeos/química , Ácidos Nicotínicos/efeitos adversos , Ácidos Nicotínicos/metabolismo , Absorção Cutânea/efeitos dos fármacos , Administração Tópica , Área Sob a Curva , Química Farmacêutica/métodos , Relação Dose-Resposta a Droga , Avaliação Pré-Clínica de Medicamentos/métodos , Eritema/induzido quimicamente , Humanos , Lipídeos/farmacologia , Lipossomos , Ácidos Nicotínicos/administração & dosagem , Fosfatidilcolinas/química , Fosfatidilcolinas/farmacologia , Absorção Cutânea/fisiologia , Espectrofotometria/métodos , Tecnologia Farmacêutica/métodos
10.
Curr Protein Pept Sci ; 4(3): 231-51, 2003 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-12769721

RESUMO

The pancreatic Kunitz inhibitor, also known as aprotinin, bovine basic pancreatic trypsin inhibitor (BPTI), and trypsin-kallikrein inhibitor, is one of the most extensively studied globular proteins. It has proved to be a particularly attractive and powerful tool for studying protein conformation as well as molecular bases of protein/protein interaction(s) and (macro)molecular recognition. BPTI has a relatively broad specificity, inhibiting trypsin- as well as chymotrypsin- and elastase-like serine (pro)enzymes endowed with very different primary specificity. BPTI reacts rapidly with serine proteases to form stable complexes, but the enzyme: inhibitor complex formation may involve several intermediates corresponding to discrete reaction steps. Moreover, BPTI inhibits the nitric oxide synthase type-I and -II action and impairs K+ transport by Ca2+-activated K+ channels. Clinically, the use of BPTI in selected surgical interventions, such as cardiopulmonary surgery and orthotopic liver transplantation, is advised, as it significantly reduces hemorrhagic complications and thus blood-transfusion requirements. Here, the structural, inhibition, and bio-medical aspects of BPTI are reported.


Assuntos
Aprotinina/análogos & derivados , Aprotinina/química , Doença Aguda , Sequência de Aminoácidos , Animais , Aprotinina/metabolismo , Aprotinina/uso terapêutico , Bovinos , Quimotripsina/antagonistas & inibidores , Cinética , Modelos Moleculares , Pancreatite/tratamento farmacológico , Conformação Proteica , Estrutura Terciária de Proteína , Homologia de Sequência de Aminoácidos , Serina Endopeptidases/metabolismo , Termodinâmica , Inibidores da Tripsina/metabolismo
11.
Biomaterials ; 25(1): 159-70, 2004 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-14580919

RESUMO

Bioadhesive and biodegradable microspheres were obtained by chemical cross-linking with epichlorohydrin of an alkaline solution of a mixture of starch and alpha-, beta-, or gamma-cyclodextrin (CyD). Microspheres were characterized by scanning electron microscopy, swelling degree, and water retention. The percentage of the effective CyD in microspheres was estimated by measuring the amount of iodine and typical organic compounds (TOCs) retained in the hydrophobic cavity of CyD. Gabexate Mesylate (trade name Foy); GM), an antiallergic drug, was included in microspheres by soaking in an aqueous solution containing the drug, followed by solvent evaporation or lyophilization. UV, IR, and DSC data indicated that despite the fact that GM is a hydrophilic drug, its hydrophobic moiety close to the benzene ring is able to penetrate the CyD cavity and to form stable inclusion complexes. Values of the association equilibrium constant for GM binding to CyD, obtained by UV differential spectroscopy, indicated that the affinity of the drug for alpha- and gamma-CyD is higher than that for beta-CyD. In vitro, GM was gradually released during 1h. Even if the release rate of the drug is relatively fast, the microspheres might actually provide the best platform since the material adheres to the nasal mucosa which was proved by adhesion tests. The GM integrity was checked by comparing its anti-trypsin activity before and after release.


Assuntos
Administração Intranasal , Materiais Revestidos Biocompatíveis/química , Anticoncepcionais/química , Ciclodextrinas/química , Gabexato/administração & dosagem , Gabexato/farmacocinética , Mucosa Intestinal/metabolismo , Amido/química , Adesivos/síntese química , Adesivos/química , Animais , Materiais Revestidos Biocompatíveis/síntese química , Anticoncepcionais/síntese química , Gabexato/química , Intestinos/citologia , Cinética , Masculino , Teste de Materiais , Taxa de Depuração Metabólica , Microesferas , Ratos , Rinite/tratamento farmacológico , Propriedades de Superfície , Distribuição Tecidual
12.
J Chromatogr B Analyt Technol Biomed Life Sci ; 791(1-2): 407-19, 2003 Jul 05.
Artigo em Inglês | MEDLINE | ID: mdl-12798201

RESUMO

Pullulan microspheres containing cyclodextrin (CyD) were obtained by chemical crosslinking with epichlorohydrin of an alkaline solution of pullulan (Pul) and alpha-, beta- or gamma-CyD. The amount of alpha-, beta- and gamma-CyD in microspheres was 120, 156, and 138 micromol/g, respectively, as determined from the percentage of iodine incorporated in the hydrophobic cavity of CyD's. Microspheres were packed in a glass column and the liquid chromatographic behaviour by isocratic elution of different drugs or typical organic compounds (TOC), taken as model drugs, was investigated. The increase of the retention volume (V(R)) of each compound, depending on the interaction(s) between CyD's cavity and the considered molecule, is characterized by a broadening of the peaks. The interaction coefficient K, corresponding to the ratio between the V(R) value of each tested molecule on Pul-alpha-, Pul-beta- and Pul-gamma-CyD active stationary phase and the V(R) value of benzoic acid on St/maltodextrin neutral stationary phase, was determined. According to K values, the accurate prediction can be done on the potential drugs to be conditioned in suitable CyD cavity. Values of K allow to anticipate the release profiles of drugs considered.


Assuntos
Ciclodextrinas/química , Glucanos/química , Farmacocinética , Microesferas , Espectrofotometria Ultravioleta
13.
Int J Pharm ; 242(1-2): 329-34, 2002 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-12176273

RESUMO

The aim of the present paper was to study production of methacrylate microparticles for the delivery (administration) of ascorbic acid via the oral route. Vitamin C is an important antioxidant that may be involved in the reduction of the risk of certain types of cancer, such as colorectal cancer. As polymers different acrylic compounds were considered, namely Eudragit RL, L and RS. Spray-drying was used as preparation method of vitamin C/Eudragit microspheres. Microspheres were first characterized by size and morphology by scanning electron microscopy, then in vitro release kinetics by mean of dialysis method were studied. Although the produced microparticles were unable to slow down the release of the drug with respect to the free form of ascorbic acid, these microspheres showed a good morphology and size distribution that permit to propose them as candidate for the delivery of vitamin C as associated therapy in the treatment of colorectal cancer by oral route.


Assuntos
Antioxidantes/administração & dosagem , Ácido Ascórbico/administração & dosagem , Composição de Medicamentos/métodos , Ácidos Polimetacrílicos/química , Antioxidantes/química , Ácido Ascórbico/química , Excipientes , Concentração de Íons de Hidrogênio , Cinética , Microscopia Eletrônica de Varredura , Microesferas , Tamanho da Partícula
14.
Int J Pharm ; 285(1-2): 87-96, 2004 Nov 05.
Artigo em Inglês | MEDLINE | ID: mdl-15488682

RESUMO

Poly(vinyl alcohol) (PVA) microspheres containing cyclodextrin (CD) were obtained by chemical cross-linking with glutaraldehyde of an acidified mixture solution of PVA and alpha-, beta- or gamma-CD. The amount of linked CD in microspheres, estimated by tetrazolium blue method, decreases in the order beta- > gamma- > alpha-CD. The dimensions of PVA/gamma-CD microspheres are much higher than those of PVA/alpha- and beta-CD. The cross-linking density of microspheres was estimated by the amount of iodine retained by the polymer matrix. The pore size as well as the porous volume of PVA/CD microspheres decrease significantly on increasing the amount of glutaraldehyde, but are enough large to permit the access of drugs to the CD cavity. In order to test the PVA/CD microsphere inclusion ability, the microspheres were packed in a glass column and the liquid chromatographic behaviour by isocratic elution of different drugs or typical organic compounds, taken as model drugs, was investigated.


Assuntos
Química Farmacêutica/métodos , Ciclodextrinas/síntese química , Portadores de Fármacos/química , Microesferas , Álcool de Polivinil/síntese química , Reagentes de Ligações Cruzadas/química , Portadores de Fármacos/farmacocinética , Glutaral/química , Tamanho da Partícula , Veículos Farmacêuticos/química , Veículos Farmacêuticos/farmacocinética , Porosidade , Tecnologia Farmacêutica/métodos
15.
AAPS PharmSci ; 5(4): E30, 2003 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-15198518

RESUMO

This article describes the production and characterization of monoglyceride-based supramolecular systems by a simple processing technique, avoiding time-consuming procedures, high energy input, and the use of organic solvents. A preformulatory study was performed to study the influence of the experimental parameters on the production of monoglyceride-based disperse systems. In particular the effects of (1) stirring speed, (2) type and concentration of monoglyceride mixture, and (3) type and concentration of surfactant were investigated on the recovery, fraction of larger particles, mean diameter, and shape of smaller particles (so called nanosomes). Dispersions were first characterized by optical microscopy and freeze-fracture electron microscopy. The mean diameter of standard nanosomes, analyzed by photon correlation spectroscopy (PCS) after elimination of larger particles by filtration, was 193.5 nm. Cryotransmission electron microscopy studies, conducted in order to investigate the structure of dispersions, showed the coexistence of vesicles and particles characterized by a cubic organization. X-ray diffraction data revealed the coexistence of 2 different cubic phases, the first being a bicontinuous cubic phase of spatial symmetry Im3m (Q229) and the second belonging to the Pn3m spatial symmetry. A study on the stability of monoglyceride-based dispersions based on macroscopical analysis of organoleptic properties and dimensional analysis by time was performed after elimination of larger particles by filtration. Organoleptic and morphological features do not change by time, appearing free from phase-separation phenomena for almost 1 year from production. PCS studies showed that nanosomes undergo an initial increase in mean diameter within the first month following production; afterwards they generally maintain their dimensions for the next 4 months.


Assuntos
Química Farmacêutica , Glicerídeos/química , Tensoativos/química , Estabilidade de Medicamentos , Microscopia Eletrônica , Nanotecnologia , Tamanho da Partícula , Solventes/química , Análise Espectral , Difração de Raios X
16.
J Cosmet Sci ; 55(3): 253-64, 2004.
Artigo em Inglês | MEDLINE | ID: mdl-15264053

RESUMO

The basic properties and the in vitro release rate kinetics of azelaic acid (AA), alternatively vehiculated in different phospholipid-based vesicles such as ethosomes or liposomes, were investigated. Ethosomes were produced by a simple method based on addition of an aqueous phase to an ethanol solution (comprised between 20\% and 45%, v/v) of soy phosphatidyl choline (5%, w/w) and AA (0.2%, w/w) under mechanical stirring. Liposomes were obtained by the same composition in the absence of ethanol with the reverse-phase evaporation method. Vesicle size was measured by photon correlation spectroscopy (PCS), evidencing smaller mean diameters and narrower dimensional distributions in the case of ethosomes with respect to liposomes. In order to obtain homogeneously sized vesicles, both ethosomal and liposomal dispersions were extruded through polycarbonate membranes with pores of calibrated diameter (400 nm and 200 nm). Vesicle morphology was characterized by freeze-fracture scanning electron microscopy (SEM) showing the presence of unilamellar vesicles both in liposome- and in ethosome-based dispersions. Free energy measurements of the vesicle bilayers were conducted by differential scanning calorimetry (DSC). AA diffusion from ethosomal or liposomal dispersions and from ethosomes and liposomes incorporated in a viscous gel was investigated by a Franz cell assembled with synthetic membranes. The release rate was more rapid from ethosomal systems than from liposomal systems. In particular, ethosomes produced by the highest ethanol concentration released AA more rapidly, and the same trend was found using viscous forms.


Assuntos
Fármacos Dermatológicos/química , Ácidos Dicarboxílicos/química , Excipientes/química , Lipossomos/química , Administração Tópica , Varredura Diferencial de Calorimetria , Química Farmacêutica , Ácidos Dicarboxílicos/administração & dosagem , Difusão , Técnica de Fratura por Congelamento , Géis/química , Cinética , Microscopia Eletrônica de Varredura
17.
J Cosmet Sci ; 54(3): 239-50, 2003.
Artigo em Inglês | MEDLINE | ID: mdl-12858223

RESUMO

A study of the diffusion of parabens from topical formulations is presented here. In particular, four different topical formulations, namely, a water-in-oil emulsion, an oil-in-water emulsion, and two hydrophilic gels (Pemulen gel and Carbopol gel) were produced, containing a mixture of three common parabens, namely, methylparaben (MP), ethylparaben (EP), and propylparaben (PP). An analytical method based on liquid extraction, followed by reversed-phase HPLC for the quantitative determination of MP, EP, and PP, was developed. The method allowed good separation of paraben mixtures and high percentages of recovery (> than 97%). The diffusion kinetics of parabens from the produced formulations was determined by an in vitro system based on a Franz cell assembled with a synthetic membrane, followed by a reversed-phase HPLC analytical method. The comparative study demonstrated that, in the case of emulsions, diffusion coefficients are a function of the substituent of preservatives: the higher the solubility, the higher the diffusion of parabens. On the contrary, in the case of the hydrophilic gels, the higher the parabens solubility, the lower the diffusion coefficients. The method described here could represent a means of controlling the extent of diffusion of parabens from topical formulations in order to minimize percutaneous absorption and to control the availability of microbes.


Assuntos
Formas de Dosagem , Parabenos/química , Cromatografia Líquida de Alta Pressão , Difusão
18.
Mater Sci Eng C Mater Biol Appl ; 33(1): 383-9, 2013 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-25428085

RESUMO

The stable, transparent, organogels, which are prepared by adding a minute amount of water to a solution of lecithin in biocompatible oil, are here studied as matrices for solubilization and percutaneous delivery of fenretinide (4 hydroxypropyl phenyl retinamide, 4HPR), a retinoic acid derivative. The influence of different types of oil, content of water and presence of hyaluronic acid was studied on gel properties. Rheology studies were carried out in order to detect the effect of these variables on gel viscosity. 4HPR diffusion from the different organogels was determined by in vitro Franz cell. It was found that diffusion coefficients (Jn) of 4HPR incorporated in organogels are about five fold lower than Jn of 4HPR in organic solution. Stability and shelf life stability studies demonstrate that 4HPR incorporated in organogels does not degrade and that organogels maintain 90% of 4HPR stability for periods up to 4 months.


Assuntos
Fenretinida/química , Géis/química , Difusão , Ácido Hialurônico/química , Cinética , Lecitinas/química , Reologia , Solubilidade , Viscosidade , Água/química
19.
Int J Pharm ; 440(2): 229-37, 2013 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-22743007

RESUMO

The purpose of this study was to investigate the potential of intranasal immunization with non-ionic surfactant vesicles (NISV) containing either the secretory recombinant form of glycoprotein B (gBs) of herpes simplex virus type 1 or a related polylysine reach peptides (DTK) for induction of protective immunity against genital herpes infection in mice. NISV were prepared by lipid film hydration method. The mean diameter of vesicles was around 390 nm for DTK-containing NISV (DTK-NISV) and 320 nm for gB1s-containing NISV (gB1s-NISV). The encapsulation efficiency of the molecules was comprised between 57% and 70%. After 7-14 day NISV maintained stable dimensions and a drug encapsulation higher than 48%. We showed that intranasal immunization with gB1s-NISV induces gB-specific IgG antibody and lymphoproliferative responses, whereas vaccination with DTK-NISV was not able to generate a gB-specific immune response. Our results indicate that vaccination of BALB/c mice with gB1s-NISV induced Th1 responses, as characterized by increased titre of IG2a in plasma and IFN-production in CD4+ splenic cells. Intranasal immunization with gB1s-NISV could elicit 90% (almost complete) protection against a heterologous lethal vaginal challenge with herpes simplex virus type 2. These data may have implications for the development of a mucosal vaccine against genital herpes.


Assuntos
Herpes Genital/prevenção & controle , Vacinas contra o Vírus do Herpes Simples/uso terapêutico , Imunização/métodos , Lipossomos/uso terapêutico , Tensoativos/uso terapêutico , Administração Intranasal , Animais , Anticorpos Antivirais/sangue , Chlorocebus aethiops , Citocinas/metabolismo , Proteínas de Drosophila/administração & dosagem , Proteínas de Drosophila/imunologia , Herpes Genital/sangue , Herpes Genital/imunologia , Vacinas contra o Vírus do Herpes Simples/administração & dosagem , Vacinas contra o Vírus do Herpes Simples/imunologia , Herpesvirus Humano 2/imunologia , Humanos , Imunoglobulina G/imunologia , Imunoglobulina G/metabolismo , Lipossomos/administração & dosagem , Lipossomos/síntese química , Ativação Linfocitária/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Tamanho da Partícula , Precursores de Proteínas/administração & dosagem , Precursores de Proteínas/imunologia , Baço/imunologia , Baço/metabolismo , Tensoativos/administração & dosagem , Tensoativos/química , Taquicininas/administração & dosagem , Taquicininas/imunologia , Células Vero , Proteínas do Envelope Viral/administração & dosagem , Proteínas do Envelope Viral/imunologia , Proteínas do Envelope Viral/uso terapêutico
20.
Mater Sci Eng C Mater Biol Appl ; 33(1): 411-8, 2013 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-25428089

RESUMO

In this study a formulation suitable to be applied on oral and/or vaginal mucosa has been developed for the treatment of fungal infections. The aim of the research is a comparison between clotrimazole (CLO) containing semisolid formulations based on monoolein aqueous dispersion (MAD) or nanostructured lipid carrier (NLC). MAD and NLC have been characterized in terms of morphology and dimensional distribution by cryogenic Transmission Electron Microscopy (cryo-TEM) and Photon Correlation Spectroscopy (PCS). CLO was encapsulated with high entrapment efficiency both in MAD and in NLC, according to Sedimentation Field Flow Fractionation (SdFFF) combined with HPLC. CLO recovery in MAD and NLC has been investigated by time. In order to obtain formulations with suitable viscosity for mucosal application, MAD was diluted with a carbomer gel, while NLC was directly viscosized by the addition of poloxamer 407 in the dispersion. The rheological properties of MAD and NLC after viscosizing have been investigated. Franz cell has been employed to study CLO diffusion from the different vehicles, evidencing diffusion rates from MAD and NLC superimposable to that obtained using Canesten(®). An anticandidal activity study demonstrated that both CLO-MAD and CLO-NLC were more active against Candida albicans with respect to the pure drug.


Assuntos
Antifúngicos/química , Clotrimazol/química , Géis/química , Nanopartículas/química , Administração através da Mucosa , Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Clotrimazol/farmacologia , Difusão , Portadores de Fármacos/química , Microscopia Eletrônica de Transmissão , Tamanho da Partícula , Poloxâmero/química , Reologia , Viscosidade
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