2013
|
Dalmoro, Annalisa; D'Amore, Matteo; Barba, Anna Angela Droplet size prediction in the production of drug delivery microsystems by ultrasonic atomization. Journal Article Translational medicine @ UniSa, 7 (2), pp. 6–11, 2013, ISSN: 2239-9747. Abstract | Links | BibTeX | Tags: dimensionless, Micro and Nano Vectors, microparticles size prediction, numbers in atomization, ultrasonic atomization @article{Dalmoro2013,
title = {Droplet size prediction in the production of drug delivery microsystems by ultrasonic atomization.},
author = { Annalisa Dalmoro and Matteo D'Amore and Anna Angela Barba},
url = {http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=3829785&tool=pmcentrez&rendertype=abstract},
issn = {2239-9747},
year = {2013},
date = {2013-01-01},
journal = {Translational medicine @ UniSa},
volume = {7},
number = {2},
pages = {6--11},
publisher = {Universit},
abstract = {Microencapsulation processes of drugs or other functional molecules are of great interest in pharmaceutical production fields. Ultrasonic assisted atomization is a new technique to produce microencapsulated systems by mechanical approach. It seems to offer several advantages (low level of mechanical stress in materials, reduced energy request, reduced apparatuses size) with respect to more conventional techniques. In this paper the groundwork of atomization is briefly introduced and correlations to predict droplet size starting from process parameters and material properties are presented.},
keywords = {dimensionless, Micro and Nano Vectors, microparticles size prediction, numbers in atomization, ultrasonic atomization},
pubstate = {published},
tppubtype = {article}
}
Microencapsulation processes of drugs or other functional molecules are of great interest in pharmaceutical production fields. Ultrasonic assisted atomization is a new technique to produce microencapsulated systems by mechanical approach. It seems to offer several advantages (low level of mechanical stress in materials, reduced energy request, reduced apparatuses size) with respect to more conventional techniques. In this paper the groundwork of atomization is briefly introduced and correlations to predict droplet size starting from process parameters and material properties are presented. |
2012
|
Dalmoro, Annalisa; Barba, Anna Angela; Lamberti, Gaetano; Grassi, Mario; D'Amore, Matteo Pharmaceutical applications of biocompatible polymer blends containing sodium alginate Journal Article Advances in Polymer Technology, 31 (3), pp. 219–230, 2012, ISSN: 07306679. Abstract | Links | BibTeX | Tags: Alginate gel film, Alginate shell{–}core particles, Biocompatibility, Crosslinking, Hydrogel Characterization, Hydrogels, Micro and Nano Vectors @article{Dalmoro2012a,
title = {Pharmaceutical applications of biocompatible polymer blends containing sodium alginate},
author = { Annalisa Dalmoro and Anna Angela Barba and Gaetano Lamberti and Mario Grassi and Matteo D'Amore},
url = {http://doi.wiley.com/10.1002/adv.21276},
doi = {10.1002/adv.21276},
issn = {07306679},
year = {2012},
date = {2012-09-01},
journal = {Advances in Polymer Technology},
volume = {31},
number = {3},
pages = {219--230},
publisher = {Wiley Subscription Services, Inc., A Wiley Company},
abstract = {Biocompatible polymer blends, such as alginate blends, have a widespread use in pharmaceutical and medical applications due to their specific features, such as biodegradation, adhesiveness, and thermo- and pH sensitivity and that can be obtained from the mixture composition. In this work, the use of alginate blends was tested in a novel production methodology of therapeutic dosage forms based on polymeric chain reticulation phenomena induced by exposure to bivalent ions. Two kinds of sodium alginate were used to obtain gel films (structured films) in blends with Pluronic F127®. The blends were considered for applications in gel paving of drug-eluting stents. Sodium alginate was also used in shell\textendashcore particle production (structured particles) to obtain shell-barrier reducing drug release in the preparative steps (see wash operations). Both structures, films and particles, were obtained using Cu2+ and Ca2+ ions, respectively. Film/shell barrier properties were tested in dissolution experiments using vitamin B12 as an active molecule model. Experimental work demonstrated that the alginate composition is a crucial point in defining reticulated structures.},
keywords = {Alginate gel film, Alginate shell{\textendash}core particles, Biocompatibility, Crosslinking, Hydrogel Characterization, Hydrogels, Micro and Nano Vectors},
pubstate = {published},
tppubtype = {article}
}
Biocompatible polymer blends, such as alginate blends, have a widespread use in pharmaceutical and medical applications due to their specific features, such as biodegradation, adhesiveness, and thermo- and pH sensitivity and that can be obtained from the mixture composition. In this work, the use of alginate blends was tested in a novel production methodology of therapeutic dosage forms based on polymeric chain reticulation phenomena induced by exposure to bivalent ions. Two kinds of sodium alginate were used to obtain gel films (structured films) in blends with Pluronic F127®. The blends were considered for applications in gel paving of drug-eluting stents. Sodium alginate was also used in shell–core particle production (structured particles) to obtain shell-barrier reducing drug release in the preparative steps (see wash operations). Both structures, films and particles, were obtained using Cu2+ and Ca2+ ions, respectively. Film/shell barrier properties were tested in dissolution experiments using vitamin B12 as an active molecule model. Experimental work demonstrated that the alginate composition is a crucial point in defining reticulated structures. |
Dalmoro, Annalisa; Barba, Anna Angela; Lamberti, Gaetano; D'Amore, Matteo Intensifying the microencapsulation process: Ultrasonic atomization as an innovative approach Journal Article European Journal of Pharmaceutics and Biopharmaceutics, 80 (3), pp. 471–477, 2012, ISSN: 09396411. Abstract | Links | BibTeX | Tags: Atomization assisted by ultrasonic energy, Micro and Nano Vectors, microencapsulation, Microparticles production, Process intensification @article{Dalmoro2012,
title = {Intensifying the microencapsulation process: Ultrasonic atomization as an innovative approach},
author = { Annalisa Dalmoro and Anna Angela Barba and Gaetano Lamberti and Matteo D'Amore},
url = {http://www.sciencedirect.com/science/article/pii/S0939641112000070},
doi = {10.1016/j.ejpb.2012.01.006},
issn = {09396411},
year = {2012},
date = {2012-04-01},
journal = {European Journal of Pharmaceutics and Biopharmaceutics},
volume = {80},
number = {3},
pages = {471--477},
abstract = {In this review, new approaches to the microencapsulation processes, widely used in the manufacturing of pharmaceutical products, are discussed focusing the attention on the emerging ultrasonic atomization technique. Fundamentals and novel aspects are presented, and advantages of ultrasonic atomization in terms of intensification and low energy requests are emphasized.},
keywords = {Atomization assisted by ultrasonic energy, Micro and Nano Vectors, microencapsulation, Microparticles production, Process intensification},
pubstate = {published},
tppubtype = {article}
}
In this review, new approaches to the microencapsulation processes, widely used in the manufacturing of pharmaceutical products, are discussed focusing the attention on the emerging ultrasonic atomization technique. Fundamentals and novel aspects are presented, and advantages of ultrasonic atomization in terms of intensification and low energy requests are emphasized. |
Barba, Anna Angela; Dalmoro, Annalisa; D'Amore, Matteo; Lamberti, Gaetano Controlled Release of Drugs from Microparticles Produced by Ultrasonic Assisted Atomization Based on Biocompatible Polymers Journal Article Chemical and Biochemical Engineering Quarterly, 26 (4), pp. 345–353, 2012, ISSN: 0352-9568. Abstract | Links | BibTeX | Tags: Micro and Nano Vectors @article{Barba2012b,
title = {Controlled Release of Drugs from Microparticles Produced by Ultrasonic Assisted Atomization Based on Biocompatible Polymers},
author = { Anna Angela Barba and Annalisa Dalmoro and Matteo D'Amore and Gaetano Lamberti},
url = {http://hrcak.srce.hr/index.php?show=clanak&id_clanak_jezik=138369},
issn = {0352-9568},
year = {2012},
date = {2012-01-01},
journal = {Chemical and Biochemical Engineering Quarterly},
volume = {26},
number = {4},
pages = {345--353},
publisher = {Hrvatsko dru\v{s}tvo kemijskih in\v{z}enjera i tehnologa},
abstract = {Microencapsulation of active molecules in biocompatible polymers is a matter of great interest in pharmaceutical sciences. Ultrasonic assisted atomization as a new technique to produce microencapsulated systems seems to offer several advantages (low level of mechanical stress in materials, reduced energy request, reduced apparatuses size) with respect to more conventional techniques. In this work, fine drug-loaded particles were produced by ionic reticulation of droplets obtained by ultrasonic atomization of biopolymers solutions. The particles were then characterized in terms of morphology and drug release kinetics. Data were used to estimate the PNMS (Polymeric Network Mesh-Size) with the aims of clarifying its role in controlled drug release, and analyzing its relationships with material and process parameters. For materials and operative conditions investigated, the calculated PNMS was found consistent with a fast release of drugs of small molecular size.},
keywords = {Micro and Nano Vectors},
pubstate = {published},
tppubtype = {article}
}
Microencapsulation of active molecules in biocompatible polymers is a matter of great interest in pharmaceutical sciences. Ultrasonic assisted atomization as a new technique to produce microencapsulated systems seems to offer several advantages (low level of mechanical stress in materials, reduced energy request, reduced apparatuses size) with respect to more conventional techniques. In this work, fine drug-loaded particles were produced by ionic reticulation of droplets obtained by ultrasonic atomization of biopolymers solutions. The particles were then characterized in terms of morphology and drug release kinetics. Data were used to estimate the PNMS (Polymeric Network Mesh-Size) with the aims of clarifying its role in controlled drug release, and analyzing its relationships with material and process parameters. For materials and operative conditions investigated, the calculated PNMS was found consistent with a fast release of drugs of small molecular size. |
Barba, Anna Angela; Dalmoro, Annalisa; D'Amore, Matteo An engineering approach to biomedical sciences: advanced strategies in drug delivery systems production Journal Article Translational Medicine@ UniSa, 4 , pp. 5–11, 2012. Abstract | BibTeX | Tags: Micro and Nano Vectors, microwave heating, Process intensification, ultrasonic atomization @article{Barba2012a,
title = {An engineering approach to biomedical sciences: advanced strategies in drug delivery systems production},
author = { Anna Angela Barba and Annalisa Dalmoro and Matteo D'Amore},
year = {2012},
date = {2012-01-01},
journal = {Translational Medicine@ UniSa},
volume = {4},
pages = {5--11},
publisher = {Universit},
abstract = {Development and optimization of novel production techniques for drug delivery systems are fundamental steps in the “from the bench to the bedside” process which is the base of translational medicine. In particular, in the current scenery where the need for reducing energy consumption, emissions, wastes and risks drives the development of sustainable processes, new pharmaceutical manufacturing does not constitute an exception. In this paper, concepts of process intensification are presented and their transposition in drug delivery systems production is discussed. Moreover, some examples on intensified techniques, for drug microencapsulation and granules drying, are reported.},
keywords = {Micro and Nano Vectors, microwave heating, Process intensification, ultrasonic atomization},
pubstate = {published},
tppubtype = {article}
}
Development and optimization of novel production techniques for drug delivery systems are fundamental steps in the “from the bench to the bedside” process which is the base of translational medicine. In particular, in the current scenery where the need for reducing energy consumption, emissions, wastes and risks drives the development of sustainable processes, new pharmaceutical manufacturing does not constitute an exception. In this paper, concepts of process intensification are presented and their transposition in drug delivery systems production is discussed. Moreover, some examples on intensified techniques, for drug microencapsulation and granules drying, are reported. |
2010
|
Dalmoro, Annalisa; Lamberti, Gaetano; Titomanlio, Giuseppe; Barba, Anna Angela; D'Amore, Matteo Enteric Micro-Particles for Targeted Oral Drug Delivery Journal Article AAPS PharmSciTech, 11 (4), pp. 1500–1507, 2010, ISSN: 1530-9932. Abstract | Links | BibTeX | Tags: coating, drug targeting, emulsion, Micro and Nano Vectors, microencapsulation, polymeric drug delivery systems @article{Dalmoro2010a,
title = {Enteric Micro-Particles for Targeted Oral Drug Delivery},
author = { Annalisa Dalmoro and Gaetano Lamberti and Giuseppe Titomanlio and Anna Angela Barba and Matteo D'Amore},
url = {http://www.springerlink.com/index/10.1208/s12249-010-9528-3},
doi = {10.1208/s12249-010-9528-3},
issn = {1530-9932},
year = {2010},
date = {2010-12-01},
journal = {AAPS PharmSciTech},
volume = {11},
number = {4},
pages = {1500--1507},
publisher = {Springer US},
abstract = {This work is focused on production of enteric-coated micro-particles for oral administration, using a water-in-oil-in-water solvent evaporation technique. The active agent theophylline was first encapsulated in cellulose acetate phthalate (CAP), a pH-sensitive well-known polymer, which is insoluble in acid media but dissolves at neutral pH (above pH 6). In this first step, CAP was chosen with the aim optimizing the preparation and characterization methods. The desired release pattern has been obtained (low release at low pH, higher release at neutral pH) but in presence of a low encapsulation efficiency. Then, the CAP was replaced by a novel-synthesized pH-sensitive poly(methyl methacrylate\textendashacrylic acid) copolymer, poly(MMA\textendashAA). In this second step, the role of two process parameters was investigated, i.e., the percentage of emulsion stabilizer (polyvinyl alcohol, PVA) and the stirring power for the double emulsion on the encapsulation efficiency. The encapsulation efficiency was found to increase with PVA percentage and to decrease with the stirring power. By increasing the PVA content and by decreasing the stirring power, a high stable double emulsion was obtained, and this explains the increase in encapsulation efficiency found.},
keywords = {coating, drug targeting, emulsion, Micro and Nano Vectors, microencapsulation, polymeric drug delivery systems},
pubstate = {published},
tppubtype = {article}
}
This work is focused on production of enteric-coated micro-particles for oral administration, using a water-in-oil-in-water solvent evaporation technique. The active agent theophylline was first encapsulated in cellulose acetate phthalate (CAP), a pH-sensitive well-known polymer, which is insoluble in acid media but dissolves at neutral pH (above pH 6). In this first step, CAP was chosen with the aim optimizing the preparation and characterization methods. The desired release pattern has been obtained (low release at low pH, higher release at neutral pH) but in presence of a low encapsulation efficiency. Then, the CAP was replaced by a novel-synthesized pH-sensitive poly(methyl methacrylate–acrylic acid) copolymer, poly(MMA–AA). In this second step, the role of two process parameters was investigated, i.e., the percentage of emulsion stabilizer (polyvinyl alcohol, PVA) and the stirring power for the double emulsion on the encapsulation efficiency. The encapsulation efficiency was found to increase with PVA percentage and to decrease with the stirring power. By increasing the PVA content and by decreasing the stirring power, a high stable double emulsion was obtained, and this explains the increase in encapsulation efficiency found. |
Dalmoro, Annalisa; Galdi, Ivan; Lamberti, Gaetano; Titomanlio, Giuseppe; Barba, Anna Angela; D'Amore, Matteo Targeted oral drug delivery by pH-sensitive microparticles Inproceedings Proceedings on CD-ROM of CHISA 2010 - ECCE 7, pp. 1–3, Chisa 2010, Praha, Czech Republic, 2010. BibTeX | Tags: @inproceedings{a.2010-2,
title = {Targeted oral drug delivery by pH-sensitive microparticles},
author = { Annalisa Dalmoro and Ivan Galdi and Gaetano Lamberti and Giuseppe Titomanlio and Anna Angela Barba and Matteo D'Amore},
year = {2010},
date = {2010-08-01},
booktitle = {Proceedings on CD-ROM of CHISA 2010 - ECCE 7},
pages = {1--3},
publisher = {Chisa 2010},
address = {Praha, Czech Republic},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
|
Galdi, Ivan; Dalmoro, Annalisa; Lamberti, Gaetano; Titomanlio, Giuseppe; Barba, Anna Angela; D'Amore, Matteo Modeling of the controlled drug release from solid matrices based on swellable/erodible polymeric hydrogels Inproceedings Proceedings of CHISA 2010 - ECCE 7, pp. 1–3, Chisa 2010, Praha, Czech Republic, 2010. BibTeX | Tags: Hydrogel Modeling @inproceedings{i.2010,
title = {Modeling of the controlled drug release from solid matrices based on swellable/erodible polymeric hydrogels},
author = { Ivan Galdi and Annalisa Dalmoro and Gaetano Lamberti and Giuseppe Titomanlio and Anna Angela Barba and Matteo D'Amore},
year = {2010},
date = {2010-08-01},
booktitle = {Proceedings of CHISA 2010 - ECCE 7},
pages = {1--3},
publisher = {Chisa 2010},
address = {Praha, Czech Republic},
keywords = {Hydrogel Modeling},
pubstate = {published},
tppubtype = {inproceedings}
}
|
Dalmoro, Annalisa; Galdi, Ivan; Lamberti, Gaetano; Titomanlio, Giuseppe; Barba, Anna Angela; D'Amore, Matteo PH-sensitive microparticles for enteric drug delivery by solvent evaporation from double emulsion Inproceedings Proceedings on CD-ROM of PBP 7, pp. 1–4, PBP Organization, La Valletta, Malta, 2010. BibTeX | Tags: @inproceedings{dalmoro2010b,
title = {PH-sensitive microparticles for enteric drug delivery by solvent evaporation from double emulsion},
author = { Annalisa Dalmoro and Ivan Galdi and Gaetano Lamberti and Giuseppe Titomanlio and Anna Angela Barba and Matteo D'Amore},
year = {2010},
date = {2010-03-01},
booktitle = {Proceedings on CD-ROM of PBP 7},
pages = {1--4},
publisher = {PBP Organization},
address = {La Valletta, Malta},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
|
Galdi, Ivan; Dalmoro, Annalisa; Lamberti, Gaetano; Titomanlio, Giuseppe; Barba, Anna Angela; D'Amore, Matteo Swelling, erosion and drug release in hydrogel based solid matrices Inproceedings Prodeedings of 7th World Meeting on Pharmaceutics, Biopharmaceutics and Pharmaceutical Technology, pp. 1–2, Organization World Meeting on Pharmaceutics, Bioph, Valletta (Malta), 2010, (Proc. su CD ROM). BibTeX | Tags: @inproceedings{galdi2010-1,
title = {Swelling, erosion and drug release in hydrogel based solid matrices},
author = { Ivan Galdi and Annalisa Dalmoro and Gaetano Lamberti and Giuseppe Titomanlio and Anna Angela Barba and Matteo D'Amore},
year = {2010},
date = {2010-03-01},
booktitle = {Prodeedings of 7th World Meeting on Pharmaceutics, Biopharmaceutics and Pharmaceutical Technology},
pages = {1--2},
publisher = {Organization World Meeting on Pharmaceutics, Bioph},
address = {Valletta (Malta)},
note = {Proc. su CD ROM},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
|
Galdi, Ivan; Dalmoro, Annalisa; Lamberti, Gaetano; Titomanlio, Giuseppe; Barba, Anna Angela; D'Amore, Matteo Swelling, erosion and drug release in hydrogel based solid matrices Inproceedings Proceedings on CD-ROM of PBP 7, pp. 1–4, PBP, La Valletta, Malta, 2010. BibTeX | Tags: Hydrogel Modeling @inproceedings{galdi2010-2,
title = {Swelling, erosion and drug release in hydrogel based solid matrices},
author = { Ivan Galdi and Annalisa Dalmoro and Gaetano Lamberti and Giuseppe Titomanlio and Anna Angela Barba and Matteo D'Amore},
year = {2010},
date = {2010-03-01},
booktitle = {Proceedings on CD-ROM of PBP 7},
pages = {1--4},
publisher = {PBP},
address = {La Valletta, Malta},
keywords = {Hydrogel Modeling},
pubstate = {published},
tppubtype = {inproceedings}
}
|
Dalmoro, Annalisa; Villano, Oriana; Barba, Anna Angela; Lamberti, Gaetano Dosare dove serve Journal Article NCF-Notiziario Chimico Farmaceutico, 49 (4), pp. 112–114, 2010, ISSN: 0393-3733. BibTeX | Tags: Micro and Nano Vectors @article{Dalmoro2010,
title = {Dosare dove serve},
author = { Annalisa Dalmoro and Oriana Villano and Anna Angela Barba and Gaetano Lamberti},
issn = {0393-3733},
year = {2010},
date = {2010-01-01},
journal = {NCF-Notiziario Chimico Farmaceutico},
volume = {49},
number = {4},
pages = {112--114},
keywords = {Micro and Nano Vectors},
pubstate = {published},
tppubtype = {article}
}
|
2009
|
Barba, Anna Angela; D'Amore, Matteo; Dalmoro, Annalisa; Lamberti, Gaetano; Titomanlio, Giuseppe Enteric coated micro-particles for targeted and controlled release Inproceedings Proceedings of CRS36, pp. 1–4, Controlled Release Society, Copenhagen, Danimarca, 2009. BibTeX | Tags: @inproceedings{barba2009-2,
title = {Enteric coated micro-particles for targeted and controlled release},
author = { Anna Angela Barba and Matteo D'Amore and Annalisa Dalmoro and Gaetano Lamberti and Giuseppe Titomanlio},
year = {2009},
date = {2009-07-01},
booktitle = {Proceedings of CRS36},
pages = {1--4},
publisher = {Controlled Release Society},
address = {Copenhagen, Danimarca},
keywords = {},
pubstate = {published},
tppubtype = {inproceedings}
}
|
Barba, Anna Angela; Chirico, Serafina; Dalmoro, Annalisa; Galzerano, Barbara; Lamberti, Gaetano Water and drug mass fraction profiles in HPMC/TP matrices Inproceedings Proceedings of CRS36, pp. 1–4, Copenhagen, Danimarca, 2009. BibTeX | Tags: Hydrogel Characterization @inproceedings{barba2009-3,
title = {Water and drug mass fraction profiles in HPMC/TP matrices},
author = { Anna Angela Barba and Serafina Chirico and Annalisa Dalmoro and Barbara Galzerano and Gaetano Lamberti},
year = {2009},
date = {2009-07-01},
booktitle = {Proceedings of CRS36},
pages = {1--4},
address = {Copenhagen, Danimarca},
keywords = {Hydrogel Characterization},
pubstate = {published},
tppubtype = {inproceedings}
}
|
Barba, Anna Angela; Dalmoro, Annalisa; Santis, Felice De; Lamberti, Gaetano Synthesis and characterization of P(MMA-AA) copolymers for targeted oral drug delivery Journal Article Polymer Bulletin, 62 (5), pp. 679–688, 2009, ISSN: 0170-0839. Abstract | Links | BibTeX | Tags: drug delivery, Enteric coating, P(MMA-AA) @article{Barba2009d,
title = {Synthesis and characterization of P(MMA-AA) copolymers for targeted oral drug delivery},
author = { Anna Angela Barba and Annalisa Dalmoro and Felice De Santis and Gaetano Lamberti},
url = {http://dx.doi.org/10.1007/s00289-009-0040-4},
doi = {10.1007/s00289-009-0040-4},
issn = {0170-0839},
year = {2009},
date = {2009-01-01},
journal = {Polymer Bulletin},
volume = {62},
number = {5},
pages = {679--688},
publisher = {Springer-Verlag},
abstract = {This paper describes the development of pH-sensitive poly(methyl methacrylate-acrylic acid) copolymers for the enteric coating of pharmaceutical products for oral administration. To obtain the dissolution at the desired pH level, different pH-sensitive polymers are available on the market. Usually, for each desired dissolution pH, an ad hoc polymer is designed. Thus, different dissolution pH values could ask for completely different polymers. Instead, the materials proposed in this work are copolymers of the same two monomers, and the different dissolution pH was obtained by changing the volume fraction of the hydrophobic methyl methacrylate monomer to the hydrophilic acrylic acid monomer. Increasing the volumetric percentage of methyl methacrylate causes the polymer to dissolve at increasing pH, until the dissolution does not take place at all, and it is replaced by a slow swelling phenomenon. The copolymers obtained were characterized by differential scanning calorimetry, in order to evaluate their glass transition temperature, and these latter were related to %MMA. The molecular weights of the pure polymers (PAA, PMMA) were measured by intrinsic viscosity, to further validate the glass transition temperatures observed. The dissolution of the copolymers was carefully tested in buffer solutions for a dense set of pH values. A linear relationship between dissolution pH and volumetric percentage of methyl methacrylate was obtained from these measurements. As a result, for any physiological compartment, the copolymer which dissolves at the pH of interest can be easily synthesized.},
keywords = {drug delivery, Enteric coating, P(MMA-AA)},
pubstate = {published},
tppubtype = {article}
}
This paper describes the development of pH-sensitive poly(methyl methacrylate-acrylic acid) copolymers for the enteric coating of pharmaceutical products for oral administration. To obtain the dissolution at the desired pH level, different pH-sensitive polymers are available on the market. Usually, for each desired dissolution pH, an ad hoc polymer is designed. Thus, different dissolution pH values could ask for completely different polymers. Instead, the materials proposed in this work are copolymers of the same two monomers, and the different dissolution pH was obtained by changing the volume fraction of the hydrophobic methyl methacrylate monomer to the hydrophilic acrylic acid monomer. Increasing the volumetric percentage of methyl methacrylate causes the polymer to dissolve at increasing pH, until the dissolution does not take place at all, and it is replaced by a slow swelling phenomenon. The copolymers obtained were characterized by differential scanning calorimetry, in order to evaluate their glass transition temperature, and these latter were related to %MMA. The molecular weights of the pure polymers (PAA, PMMA) were measured by intrinsic viscosity, to further validate the glass transition temperatures observed. The dissolution of the copolymers was carefully tested in buffer solutions for a dense set of pH values. A linear relationship between dissolution pH and volumetric percentage of methyl methacrylate was obtained from these measurements. As a result, for any physiological compartment, the copolymer which dissolves at the pH of interest can be easily synthesized. |
Barba, Anna Angela; Chirico, Serafina; Dalmoro, Annalisa; Lamberti, Gaetano Simultaneous measurement of theophylline and cellulose acetate phthalate in phosphate buffer by UV analysis Journal Article Can J Anal Sci Spectros, 53 (6), pp. 249–253, 2009. Abstract | BibTeX | Tags: Hydrogel Characterization @article{Barba2009a,
title = {Simultaneous measurement of theophylline and cellulose acetate phthalate in phosphate buffer by UV analysis},
author = { Anna Angela Barba and Serafina Chirico and Annalisa Dalmoro and Gaetano Lamberti},
year = {2009},
date = {2009-01-01},
journal = {Can J Anal Sci Spectros},
volume = {53},
number = {6},
pages = {249--253},
abstract = {The oral administration of pH-sensitive drugs requires protecting the drug molecules from the acidic pH in the stomach: the simplest way is to use polymers as coating, especially polymers which are insoluble at low pH (in the stomach) and soluble under neutral conditions (in the intestine). The Cellulose Acetate Phosphate, CAP, is one of these polymers, and it is one of the most used coating polymers. Studies related to the behavior of such pharmaceutical systems require fast and accurate methods to assay the released drug concentration in dissolution medium. However, both the drug and the coating polymer are present in the dissolution bulk with unknown concentration, and they can interfere each other in assaying. In this communication, a simple method to assay, by UV analysis, Theophylline (TP) and Cellulose Acetate Phosphate concentrations in a dissolution medium, phosphate buffer pH 7.0 (BP), is proposed and validated.},
keywords = {Hydrogel Characterization},
pubstate = {published},
tppubtype = {article}
}
The oral administration of pH-sensitive drugs requires protecting the drug molecules from the acidic pH in the stomach: the simplest way is to use polymers as coating, especially polymers which are insoluble at low pH (in the stomach) and soluble under neutral conditions (in the intestine). The Cellulose Acetate Phosphate, CAP, is one of these polymers, and it is one of the most used coating polymers. Studies related to the behavior of such pharmaceutical systems require fast and accurate methods to assay the released drug concentration in dissolution medium. However, both the drug and the coating polymer are present in the dissolution bulk with unknown concentration, and they can interfere each other in assaying. In this communication, a simple method to assay, by UV analysis, Theophylline (TP) and Cellulose Acetate Phosphate concentrations in a dissolution medium, phosphate buffer pH 7.0 (BP), is proposed and validated. |
2007
|
Chirico, Serafina; Dalmoro, Annalisa; Lamberti, Gaetano; Russo, Giuseppina; Titomanlio, Giuseppe Analysis and modeling of swelling and erosion behavior for pure HPMC tablet Journal Article Journal of Controlled Release, 122 (2), pp. 181–188, 2007, ISSN: 01683659. Abstract | Links | BibTeX | Tags: Controlled drug release, Erosion, HPMC, Hydrogel Characterization, Hydrogel Modeling, Swelling @article{Chirico2007,
title = {Analysis and modeling of swelling and erosion behavior for pure HPMC tablet},
author = { Serafina Chirico and Annalisa Dalmoro and Gaetano Lamberti and Giuseppina Russo and Giuseppe Titomanlio},
url = {http://www.sciencedirect.com/science/article/pii/S0168365907003215},
doi = {10.1016/j.jconrel.2007.07.001},
issn = {01683659},
year = {2007},
date = {2007-09-01},
journal = {Journal of Controlled Release},
volume = {122},
number = {2},
pages = {181--188},
abstract = {This work is focused on the transport phenomena which take place during immersion in water of pure hydroxypropylmethylcellulose tablets. The water uptake, the swelling and the erosion during immersion were investigated in drug-free systems, as a preliminary task before to undertake the study of drug-loaded ones. The tablets, obtained by powder compression, were confined between glass slabs to allow water uptake only by lateral surface and then immersed in distilled water at 37 °C, with simultaneous video-recording. By image analysis the normalized light intensity profiles were obtained and taken as a measure of the water mass fraction. The time evolutions of the total tablet mass, of the water mass and of the erosion radius were measured, too. Thus a novel method to measure polymer and water masses during hydration was pointed out. Then, a model consisting in the transient mass balance, accounting for water diffusion, diffusivity change due to hydration, swelling and erosion, was found able to reproduce all experimental data. Even if the model was already used in literature, the novelty of our approach is to compare model predictions with a complete set of experimental data, confirming that the main phenomena were correctly identified and described.},
keywords = {Controlled drug release, Erosion, HPMC, Hydrogel Characterization, Hydrogel Modeling, Swelling},
pubstate = {published},
tppubtype = {article}
}
This work is focused on the transport phenomena which take place during immersion in water of pure hydroxypropylmethylcellulose tablets. The water uptake, the swelling and the erosion during immersion were investigated in drug-free systems, as a preliminary task before to undertake the study of drug-loaded ones. The tablets, obtained by powder compression, were confined between glass slabs to allow water uptake only by lateral surface and then immersed in distilled water at 37 °C, with simultaneous video-recording. By image analysis the normalized light intensity profiles were obtained and taken as a measure of the water mass fraction. The time evolutions of the total tablet mass, of the water mass and of the erosion radius were measured, too. Thus a novel method to measure polymer and water masses during hydration was pointed out. Then, a model consisting in the transient mass balance, accounting for water diffusion, diffusivity change due to hydration, swelling and erosion, was found able to reproduce all experimental data. Even if the model was already used in literature, the novelty of our approach is to compare model predictions with a complete set of experimental data, confirming that the main phenomena were correctly identified and described. |
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Chirico, Serafina; Dalmoro, Annalisa; Lamberti, Gaetano; Russo, Giuseppina; Titomanlio, Giuseppe Radial water up-take in pure HPMC tablet: analysis and model prediction Inproceedings Proceedings of Pharmaceutical Science World Congress, pp. 1–4, Amsterdam, 0000. BibTeX | Tags: Hydrogel Characterization, Hydrogel Modeling @inproceedings{chirico2007-1,
title = {Radial water up-take in pure HPMC tablet: analysis and model prediction},
author = { Serafina Chirico and Annalisa Dalmoro and Gaetano Lamberti and Giuseppina Russo and Giuseppe Titomanlio},
booktitle = {Proceedings of Pharmaceutical Science World Congress},
pages = {1--4},
address = {Amsterdam},
keywords = {Hydrogel Characterization, Hydrogel Modeling},
pubstate = {published},
tppubtype = {inproceedings}
}
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