Biomedical subjects

F Bigucci

Publications and source records attributed to F Bigucci.

14 recordsLinked to original sources

PubMed2005

Chitosan and poly(methyl vinyl ether-co-maleic anhydride) microparticles as nasal sustained delivery systems.

An original dosage form for nasal delivery based on the encapsulation of hydrophilic drug in chitosan-poly(methyl vinyl ether-co-maleic anhydride) (CH-PVM/MA) microparticles prepared by spray-drying technique was developed. Microparticles were characterized in terms of morphology, size, swelling properties, encapsulation efficiency and drug release. The physical state of the drug and the polymer was determined by scanning electron microscopy (SEM) and infrared spectroscopy (IR). Propranolol hydrochloride (PH) was a beta-blocker, used for the treatment of hypertension and was chosen as a model of hydrophilic drug. SEM studies showed spherical particles with smooth surfaces for chitosan hydrochloride (CH-HCl), whereas rather gross surface defects resulted from the incorporation of poly(methyl vinyl ether-co-maleic anhydride) (PVM/MA). In vitro release studies revealed a sustained release of propranolol HCl from microparticles and in particular chitosan hydrochloride provided the lowest release of drug.

Adhesiveness↗

PubMed2004

Polymeric nanoparticles composed of fatty acids and polyvinylalcohol for topical application of sunscreens.

Benzophenone-3 (BZP) or oxybenzone is widely used in many cosmetic formulations, such as sunscreen lotions or emulsions, shampoos and hair sprays. The nature of the vehicle used can enhance or block the percutaneous absorption of UV filter. In this work, we hydrophobically modified polyvinylalcohol 10 000 (PVA) with fatty acids (FAs) to obtain PVA-FA derivatives for the preparation of lipophilic polymeric nanoparticles able to prevent BZP movement towards the skin. Synthesized PVA-FA derivatives were confirmed by H1 NMR. Nanoparticles loaded with BZP were prepared using a solvent extraction method. The particle size was monitored by means of dynamic light scattering measurements. In-vitro skin permeation studies were performed.

Administration, Topical↗

PubMed2003

Effect of chitosan on progesterone release from hydroxypropyl-beta-cyclodextrin complexes.

An inclusion complex composed of progesterone (Prog) and hydroxypropyl-beta-cyclodextrin (HPbetaCD) was prepared by the spray-drying and freeze-drying methods. Prog alone and its inclusion complex with HPbetaCD were incorporated into chitosan by spray-drying and freeze-drying. The inclusion complex was characterized by IR and DSC. The inclusion complex was investigated in solution by phase solubility diagrams and stability constant was determined at pH 7.4 and at different temperatures (10, 25 and 37 degrees C) to obtain the thermodynamic parameters of inclusion. The results indicate that the Prog-HPbetaCD inclusion complex is more water soluble than Prog alone. Release data from all samples showed significant improvement of the dissolution rate of Prog and a controlled release is obtained in the presence of chitosan.

2-Hydroxypropyl-beta-cyclodextrin↗

PubMed2003

Chitosan salts as nasal sustained delivery systems for peptidic drugs.

The aim of this study was to describe a sustained drug release system based on chitosan salts for vancomycin hydrochloride delivery. Chitosan lactate, chitosan aspartate, chitosan glutamate and chitosan hydrochloride were prepared by spray-drying technique. Vancomycin hydrochloride was used as a model peptidic drug, the nasal sustained release of which should avoid first-pass metabolism in the liver. This in-vitro study evaluated the influence of chitosan salts on the release behaviour of vancomycin hydrochloride from the physical mixtures at pH 5.5 and 7.4. In-vitro release of vancomycin was retarded by chitosan salts and, in particular, chitosan hydrochloride provided the lowest release of vancomycin.

Administration, Intranasal↗

PubMed2002

Influence of different chitosan salts on the release of sodium diclofenac in colon-specific delivery.

Chitosan (CH) was dissolved in aqueous solutions containing aspartic, glutamic, hydrochloric, lactic and citric acids to obtain different chitosan salts. Chitosan salts were collected from the solutions by spray-drying and the powders obtained were mixed with Sodium Diclofenac (SD), taken as a model anti-inflammatory drug. This study evaluated in vitro the influence of acid type on the release behaviour of SD from the physical mixture during gastrointestinal transit. The physical mixture of the chitosan salts with SD provided slower drug release than the pure drug both in acidic and alkaline pHs. In addition, the interaction with beta-glucosidase at pH 7.0 enhanced the release rate. Among the CH salts used, glutamic and aspartic salts provided the best control of release.

Algorithms↗

PubMed2002

Hydrogels formed by crosslinked poly(vinyl alcohol) as sustained drug delivery systems.

Poly(vinyl alcohol) was crosslinked with ethylene glycol diglycidyl ether to obtain hydrogel-forming polymers. The polymers were also substituted with oleoyl chloride, providing hydrogels with weak solubility. These new polymeric materials were evaluated for the formulation of sustained drug delivery systems. Vancomycin hydrochloride was used as a peptidic model drug whose sustained release should minimize its inactivation in the upper part of the gastrointestinal tract. Spray-dried mixtures of the drug and the polymer [at 1:4 and 1:8 (w:w) ratios] were prepared and the release of the drugs from the mixtures was evaluated in vitro at pH 2.0, 5.5, 7.4, and 8.0. The results indicated that the crosslinked polymers slowed down the release of the drugs with respect to the pure drug at each pH. The degree of crosslinking of ethylene glycol diglycidyl ether and the extent of substitution with oleoyl chloride were found to influence drug release.

Anti-Bacterial Agents↗

PubMed2002

Physically cross-linked chitosan hydrogels as topical vehicles for hydrophilic drugs.

Physically cross-linked chitosan hydrogels with lauric, myristic, palmitic or stearic acid were prepared by freeze-drying and have been studied for topical use. This study selected propranolol hydrochloride as a hydrophilic model drug to design a transdermal delivery system. We evaluated the effect of the nature of the cross-linker on drug permeation through porcine skin and the main permeation parameters (diffusion coefficient, flux and lag time) were calculated. All the chitosan hydrogels analysed provided more transcutaneous permeation of propranolol hydrochloride than the corresponding solution of the commercial drug. Among the different chitosan vehicles, chitosan-laurate and chitosan-myristate hydrogels enhanced lyophilised drug diffusion through the skin with respect to chitosan-palmitate and chitosan-stearate hydrogels. This can been explained by the interaction of the hydrogels with the stratum corneum, increasing the solubility of the drug in the skin.

Administration, Cutaneous↗

PubMed2001

Self-assembling poly(vinyl alcohol) derivatives, interactions with drugs and control of release.

The self-assembling properties of poly(vinyl alcohol) substituted with 2-hydroxypropyltrimethylammonium and with acyl chains of different molecular weights (butyryl, capryloyl, lauroyl, or myristoyl) were evaluated to assess the conditions favoring interaction with a poorly soluble drug such as indomethacin to increase its availability. To evaluate the effect of drug-polymer interactions on the solubility of the drug, phase-solubility diagrams were obtained from each substituted polymer at pH 2.0, 5.5, and 7.4 in the presence of indomethacin. To evaluate the availability of the free drug in solution, release profiles of the free drug from drug-polymer physical mixtures were obtained by a dissolution-diffusion apparatus containing a dialysis membrane allowing diffusion of the free drug towards a receiving phase where its concentration was determined over time. The phase-solubility diagrams revealed increasing drug solubility on increasing the polymer concentration. The drug-polymer affinity was slightly increased by lengthening the chain of the substituent on the polymer and was strongly increased by raising the pH of the aqueous phase. The thermodynamic evaluation of the drug-polymer interactions indicated that the interaction is enthalpically driven while the increase in drug-polymer affinity with increasing chain length could be attributed to an entropic contribution. The free drug availability from the drug-polymer systems increased on enhancing the drug-polymer affinity because it corresponded to an increase in the solubilizing effect of the polymer on the drug.

Delayed-Action Preparations↗

PubMed1998

Substituted poly(methyl vinyl ether-alt-maleic anhydride) for the release control and targeting of methotrexate.

Poly(methyl vinyl ether-alt-maleic anhydride) substituted with cholamine (CA), aminoethylcholamine (AECA), or aminooctylcholamine (AOCA) at different substitution degrees, were used for methotrexate (MTX) complexation. The solid complexes, isolated by precipitation from the preparative mixture, showed lower fractional releases at pH 7.4 than at 5.5. This was ascribed to the establishment of ionic interactions between the ionized carboxyls of both the polymer and the drug and the quaternary ammonium groups of the substituents (CA, AECA, AOCA) inducing polymer self-aggregation and thus complex stabilization. The fractional release in pH 7.4 decreases with the increase in the substitution degree until a minimum characteristic for each substituent analyzed is reached and then rises with the increase in substitution degree. The minimum release at pH 7.4 was observed in the presence of AECA at the degree of substitution corresponding to 0.35 mole of substituent per mole of dimer (methyl vinyl ethermaleic anhydride). None of the substituted polymers studied had any haemolytic effect, indicating good biocompatibility.

Animals↗

PubMedDate not supplied

Controlled release of vancomycin from freeze-dried chitosan salts coated with different fatty acids by spray-drying.

The aim of this study was to describe a controlled drug release system based on chitosan salts for vancomycin hydrochloride delivery. Chitosan aspartate (CH-Asp), chitosan glutamate (CH-Glu) and chitosan hydrochloride (CH-HCl) were prepared by freeze-drying and coated with stearic, palmitic, myristic and lauric acids by spray-drying technique. Vancomycin hydrochloride was used as a peptidic model drug whose sustained release should minimize its inactivation in the upper part of the gastrointestinal tract. This study evaluated, in vitro, the influence of chitosan salts on the release behaviour of vancomycin hydrochloride from the freeze-dried and spray-dried systems at pH 2.0 and 7.4.

Anti-Bacterial Agents↗

PubMedDate not supplied

Poly(vinylalcohol-co-vinyloleate) for the preparation of micelles enhancing retinyl palmitate transcutaneous permeation.

The amphiphilic properties of poly(vinylalcohol) substituted with oleic acid was evaluated to assess the possibility to prepare polymeric micelles in an aqueous phase containing a hydrophobic core able to host lipophilic drugs such as retinyl palmitate and thereby enhance its transcutaneous absorption in the stratum corneum. The effect of the increased drug absorption suggests the possibility of interaction between the substituted polymer and the components present in the intercorneocyte spaces. Correlations between the drug concentration in the preparative mixture, micelle size, and drug permeation were evaluated to establish the best functional properties of the micellar systems enhancing retinyl palmitate absorption. Transcutaneous absorption increased with decreasing micelle size, and micelle size decreased on decreasing the drug concentration in the preparative mixture.

Administration, Cutaneous↗

PubMedDate not supplied

Bovine serum albumin nanospheres carrying progesterone inclusion complexes.

Bovine serum albumin nanospheres carrying cyclodextrin complexes for the delivery of progesterone were produced. Inclusion complexes composed of progesterone and hydroxypropyl-beta-cyclodextrin or dimethyl-beta-cyclodextrin were prepared by spray-drying or freeze-drying methods. Prog alone and its inclusion complexes were incorporated into bovine serum albumin nanospheres using a coacervation method and cross-linking with heating. The nanosphere suspensions were essicated by spray-drying or freeze-drying. The inclusion complexes and the nanospheres were characterized by Fourier Transform-Infrared Spectroscopy (FT-IR) and Differential Scanning Calorimetry (DSC). Phase-solubility diagrams and stability constants were determined in distilled water at different temperatures (10, 25, and 37 degrees C). Size of nanospheres, their drug loading capacity and swelling ability were evaluated, as well as the in vitro controlled release profiles at pH 5.5 and 7.4.

Calorimetry, Differential Scanning↗

PubMedDate not supplied

Micelles based on polyvinyl alcohol substituted with oleic acid for targeting of lipophilic drugs.

Polymeric micelles based on polyvinyl alcohol substituted with oleic acid were used as vehicles for progesterone and folic acid. The ability of this amphiphilic polymer to entrap lipophilic drugs and to generate stable micelles in aqueous neutral medium makes it a good candidate for drug delivery. The release of the loaded drugs in acidic environments represents another important property of these systems. Size of micelles, their stability, and their drug-loading capacity were evaluated, as well as the in vitro controlled-release profiles at pH 7.4 and 5.5.

Drug Delivery Systems↗

PubMedDate not supplied

Crosslinked poly(methyl vinyl ether-co-maleic anhydride) as topical vehicles for hydrophilic and lipophilic drugs.

Poly(methyl vinyl ether-co-maleic anhydride) crosslinked with ethylene glycol (GZ-ET), 1,4-butanediol (GZ-BUT), 1,6-exandiol (GZ-EX), 1,8-octanediol (GZ-OCT), 1,10-decanediol (GZ-DEC) or 1,12-dodecanediol (GZ-DOD) was prepared and employed as a supporting material for aqueous topical gels containing pyridoxine hydrochloride (PYCL) chosen as a hydrophilic model molecule or for O/A emulsion containing beta-carotene chosen as a hydrophobic model molecule. We analyzed the effect of the nature of the crosslinker on the permeation of hydrophilic and lipophilic vitamins through porcine skin by in vitro permeation studies. The vehicles formed by crosslinked poly(methyl vinyl ether-co-maleic anhydride) showed enhanced vitamins permeation with respect to the same vehicles formed by noncrosslinked poly(methyl vinyl ether-co-maleic anhydride) (GZ). The decrease in the crosslinker acyl chain length provides vehicles accelerating the drug permeability through the skin.

Administration, Topical↗