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Papers by Alessandra Rossi
European Journal of Pharmaceutical Sciences, 2017
In vitro dissolution testing is routinely used in the development of pharmaceutical products. Whi... more In vitro dissolution testing is routinely used in the development of pharmaceutical products. Whilst the dissolution testing methods are well established and standardized for oral dosage forms, i.e. tablets and capsules, there are no pharmacopoeia methods or regulatory requirements for testing the dissolution of orally inhaled powders. Despite this, a wide variety of dissolution testing methods for orally inhaled powders has been developed and their bio-relevance has been evaluated. The review provides an overview of the in vitro dissolution methodologies for dry inhalation products, with particular emphasis on dry powder inhaler, where the dissolution behavior of the respirable particles can have a role on duration and absorption of the drug. Dissolution mechanisms of respirable particles as well as kinetic models have been presented. A more recent bio-relevant dissolution setups and media for studying inhalation biopharmaceutics were also reviewed. In addition, factors affecting interplay between dissolution and absorption of deposited particles in the context of biopharmaceutical considerations of inhalation products were examined.
Controlled release of drugs is a dynamic activity of pharmaceutical companies, due to the indispu... more Controlled release of drugs is a dynamic activity of pharmaceutical companies, due to the indisputable advancement provided by delivery technology to pharmacotherapy. In addition, this activity give rise to new patented products for a market in which new substances are ...
European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences, Jan 15, 2018
This review aims in discussing the application of the Quality by Design (QbD) approach on the dev... more This review aims in discussing the application of the Quality by Design (QbD) approach on the development of the Dry Powders Inhalers (DPIs). It starts with a thorough presentation of the Quality's concept evolution within the pharmaceutical sector and how this slowly adopted set of quality guidelines is now a major scientific and regulatory requirement. DPIs represent a type of delivery system where the system's thinking approach integrating the device, the formulation and the patient represent a major challenge to be met. Within this context this review points out the critical gaps in this optimization exercise and proposes a series of remedies in overcoming the obstacles when the system's parts are viewed alone and not as a whole. Statistical thinking and the corresponding tools are the means for successfully carrying out this purpose. QbD is not just another guideline to simply comply with. It is the ultimate scope of any pharmaceutical development effort, which is t...
International Journal of Pharmaceutics, 2016
International Journal of Pharmaceutics, 2016
The bilayer tableting technology is gaining more acceptance in the drug industry, due to its abil... more The bilayer tableting technology is gaining more acceptance in the drug industry, due to its ability to improve the drug delivery strategies. It is currently assessed by the European Pharmacopoeia, that the mechanical strength of tablets can be evaluated using a diametral breaking tester. This device applies a force diametrically, and records the tablet breaking point. This approach has been used to measure the structural integrity of single layer tablets as well as bilayer (and multi-layer) tablets. The latter ones, however, have a much complex structure. Therefore, testing a bilayer tablet with the currently used breaking test methodology might not be appropriate. The aim of this work was to compare results from several tests that have been proposed to quantify the interfacial strength of bilayer tablets. The obtained results would provide an indication on which tests are appropriate to evaluate the robustness of a bilayer tablet. Bilayer tablets were fabricated using a model formulation: Microcrystalline Cellulose (MCC) for the first layer, and spray dried lactose (SDLac) as second layer. Each set of tablets were tested using the following tests: Diametral Test, Shear Test and Indentation Test. The tablets were examined before and after the breaking test using Scanning Electron Microscopy (SEM). When a bilayer tablet was subjected to shearing or indentation, it showed signs of clear delamination. Differently, using the diametral test system, the tablets showed no clear difference, before and after the testing. However, when examining each layer via SEM, it was clear that a fracture occurred in the layer made of SDLac. Thus, the diametral test is a measure of the strength of one of the two layers and therefore it is not suited to test the mechanical strength of bilayer tablets.
International journal of pharmaceutics, Jan 9, 2016
In recent decades, many efforts have been made in order to improve drug bioavailability after ora... more In recent decades, many efforts have been made in order to improve drug bioavailability after oral administration. Gastroretentive drug delivery systems are a good example; they emerged to enhance the bioavailability and effectiveness of drugs with a narrow absorption window in the upper gastrointestinal tract and/or to promote local activity in the stomach and duodenum. Several strategies are used to increase the gastric residence time, namely bioadhesive or mucoadhesive systems, expandable systems, high-density systems, floating systems, superporous hydrogels and magnetic systems. The present review highlights some of the drugs that can benefit from gastroretentive strategies, such as the factors that influence gastric retention time and the mechanism of action of gastroretentive systems, as well as their classification into single and multiple unit systems.
Journal of Drug Delivery Science and Technology, 2007
ABSTRACT Soft agglomerates containing pantoprazole gastro-resistant microparticles were prepared ... more ABSTRACT Soft agglomerates containing pantoprazole gastro-resistant microparticles were prepared for an oral delayed-release solid dosage form. A new technique was used to agglomerate the microparticles: enteric microparticles of pantoprazole, non-agglomerating per se, were blended with mannitolllecithin spray-dried microparticles, i.e. excipient microparticles. The blend was agglomerated by tumbling or sieve vibration. In order to elucidate the agglomerate formation, the effect of factors such as the amount of lecithin in the excipient microparticles, the ratio between pantoprazole and excipient microparticles and the agglomeration method were investigated by factorial design. Twelve batches of agglomerates presenting differing yield, drug loading, morphology, mechanical and release properties were prepared. The concentration of lecithin in the excipient microparticles was crucial for the agglomeration process. The biopharmaceutical characteristics of pantoprazole microparticles, i.e. their delayed-release properties, were not affected by the agglomeration process.
Drug Development and Industrial Pharmacy, 2015
Bollettino chimico farmaceutico
The properties of pharmaceutical formulations are profoundly influenced by physico-chemical inter... more The properties of pharmaceutical formulations are profoundly influenced by physico-chemical interactions, particularly those occurring between a drug and an excipient. The prediction and comprehension of these interactions provide information to use during the development of a dosage form. Thermal analysis methods are commonly utilized to obtain data from which phase diagrams can be easily constructed for a number of binary systems. The aim of this review is the classification of the phase diagrams of binary systems, as a function of two fundamental factors: 1) the relative strength of interaction between similar (UAA, UBB) and different atoms (UAB); 2) the limiting permissible degree of deformation of the energy field. The main binary phase diagrams have been analyzed starting from the simplest case, in which the two components are virtually incapable of dissolving each other either in the liquid and in the solid states, to the case where the formation of unlimited solid solutions ...
European Journal of Pharmaceutical Sciences, 2017
In vitro dissolution testing is routinely used in the development of pharmaceutical products. Whi... more In vitro dissolution testing is routinely used in the development of pharmaceutical products. Whilst the dissolution testing methods are well established and standardized for oral dosage forms, i.e. tablets and capsules, there are no pharmacopoeia methods or regulatory requirements for testing the dissolution of orally inhaled powders. Despite this, a wide variety of dissolution testing methods for orally inhaled powders has been developed and their bio-relevance has been evaluated. The review provides an overview of the in vitro dissolution methodologies for dry inhalation products, with particular emphasis on dry powder inhaler, where the dissolution behavior of the respirable particles can have a role on duration and absorption of the drug. Dissolution mechanisms of respirable particles as well as kinetic models have been presented. A more recent bio-relevant dissolution setups and media for studying inhalation biopharmaceutics were also reviewed. In addition, factors affecting interplay between dissolution and absorption of deposited particles in the context of biopharmaceutical considerations of inhalation products were examined.
Controlled release of drugs is a dynamic activity of pharmaceutical companies, due to the indispu... more Controlled release of drugs is a dynamic activity of pharmaceutical companies, due to the indisputable advancement provided by delivery technology to pharmacotherapy. In addition, this activity give rise to new patented products for a market in which new substances are ...
European journal of pharmaceutical sciences : official journal of the European Federation for Pharmaceutical Sciences, Jan 15, 2018
This review aims in discussing the application of the Quality by Design (QbD) approach on the dev... more This review aims in discussing the application of the Quality by Design (QbD) approach on the development of the Dry Powders Inhalers (DPIs). It starts with a thorough presentation of the Quality's concept evolution within the pharmaceutical sector and how this slowly adopted set of quality guidelines is now a major scientific and regulatory requirement. DPIs represent a type of delivery system where the system's thinking approach integrating the device, the formulation and the patient represent a major challenge to be met. Within this context this review points out the critical gaps in this optimization exercise and proposes a series of remedies in overcoming the obstacles when the system's parts are viewed alone and not as a whole. Statistical thinking and the corresponding tools are the means for successfully carrying out this purpose. QbD is not just another guideline to simply comply with. It is the ultimate scope of any pharmaceutical development effort, which is t...
International Journal of Pharmaceutics, 2016
International Journal of Pharmaceutics, 2016
The bilayer tableting technology is gaining more acceptance in the drug industry, due to its abil... more The bilayer tableting technology is gaining more acceptance in the drug industry, due to its ability to improve the drug delivery strategies. It is currently assessed by the European Pharmacopoeia, that the mechanical strength of tablets can be evaluated using a diametral breaking tester. This device applies a force diametrically, and records the tablet breaking point. This approach has been used to measure the structural integrity of single layer tablets as well as bilayer (and multi-layer) tablets. The latter ones, however, have a much complex structure. Therefore, testing a bilayer tablet with the currently used breaking test methodology might not be appropriate. The aim of this work was to compare results from several tests that have been proposed to quantify the interfacial strength of bilayer tablets. The obtained results would provide an indication on which tests are appropriate to evaluate the robustness of a bilayer tablet. Bilayer tablets were fabricated using a model formulation: Microcrystalline Cellulose (MCC) for the first layer, and spray dried lactose (SDLac) as second layer. Each set of tablets were tested using the following tests: Diametral Test, Shear Test and Indentation Test. The tablets were examined before and after the breaking test using Scanning Electron Microscopy (SEM). When a bilayer tablet was subjected to shearing or indentation, it showed signs of clear delamination. Differently, using the diametral test system, the tablets showed no clear difference, before and after the testing. However, when examining each layer via SEM, it was clear that a fracture occurred in the layer made of SDLac. Thus, the diametral test is a measure of the strength of one of the two layers and therefore it is not suited to test the mechanical strength of bilayer tablets.
International journal of pharmaceutics, Jan 9, 2016
In recent decades, many efforts have been made in order to improve drug bioavailability after ora... more In recent decades, many efforts have been made in order to improve drug bioavailability after oral administration. Gastroretentive drug delivery systems are a good example; they emerged to enhance the bioavailability and effectiveness of drugs with a narrow absorption window in the upper gastrointestinal tract and/or to promote local activity in the stomach and duodenum. Several strategies are used to increase the gastric residence time, namely bioadhesive or mucoadhesive systems, expandable systems, high-density systems, floating systems, superporous hydrogels and magnetic systems. The present review highlights some of the drugs that can benefit from gastroretentive strategies, such as the factors that influence gastric retention time and the mechanism of action of gastroretentive systems, as well as their classification into single and multiple unit systems.
Journal of Drug Delivery Science and Technology, 2007
ABSTRACT Soft agglomerates containing pantoprazole gastro-resistant microparticles were prepared ... more ABSTRACT Soft agglomerates containing pantoprazole gastro-resistant microparticles were prepared for an oral delayed-release solid dosage form. A new technique was used to agglomerate the microparticles: enteric microparticles of pantoprazole, non-agglomerating per se, were blended with mannitolllecithin spray-dried microparticles, i.e. excipient microparticles. The blend was agglomerated by tumbling or sieve vibration. In order to elucidate the agglomerate formation, the effect of factors such as the amount of lecithin in the excipient microparticles, the ratio between pantoprazole and excipient microparticles and the agglomeration method were investigated by factorial design. Twelve batches of agglomerates presenting differing yield, drug loading, morphology, mechanical and release properties were prepared. The concentration of lecithin in the excipient microparticles was crucial for the agglomeration process. The biopharmaceutical characteristics of pantoprazole microparticles, i.e. their delayed-release properties, were not affected by the agglomeration process.
Drug Development and Industrial Pharmacy, 2015
Bollettino chimico farmaceutico
The properties of pharmaceutical formulations are profoundly influenced by physico-chemical inter... more The properties of pharmaceutical formulations are profoundly influenced by physico-chemical interactions, particularly those occurring between a drug and an excipient. The prediction and comprehension of these interactions provide information to use during the development of a dosage form. Thermal analysis methods are commonly utilized to obtain data from which phase diagrams can be easily constructed for a number of binary systems. The aim of this review is the classification of the phase diagrams of binary systems, as a function of two fundamental factors: 1) the relative strength of interaction between similar (UAA, UBB) and different atoms (UAB); 2) the limiting permissible degree of deformation of the energy field. The main binary phase diagrams have been analyzed starting from the simplest case, in which the two components are virtually incapable of dissolving each other either in the liquid and in the solid states, to the case where the formation of unlimited solid solutions ...