Mechanical characterization of pharmaceutical solids: a comparison between rheological tests performed under static and dynamic porosity conditions.

The aim of this work was to verify how and to what extent rheological tests, carried out under dynamic (Heckel) and static (creep, stress/strain) porosity conditions, may serve as a valuable complement to the classic Heckel tests in the characterization of viscoelastic and densification properties of solid materials for pharmaceutical use. Six different modified (pregelatinized) starches were compressed in a rotary tablet machine equipped to measure force and punch displacement. Tablets were obtained using flat-faced 6 mm diameter punches at different compression pressures. Compression cycles performed at the maximal pressure of 200 MPa were used to build the Heckel plots. Ejected tablets at the 10%, 20%, 30%, and 40% porosity levels were used for the stress/strain and creep tests. Parameters obtained with both types of tests were consistent with each other. In particular, among the six starches, lower viscosity values corresponded to lower PY values, and lower elastic modulus values corresponded to lower elastic recovery of the tablet. Mechanical properties of materials can be better characterized if viscoelastic tests performed under dynamic porosity conditions (Heckel analysis) are supported by classical viscoelastic tests carried out under conditions of static porosity

Engineered Carrier with a Long Time of Flight (TOF) to Improve Drug Delivery From Dry Powder Inhalation Aerosols

A lactose carrier with long TOF was engineered to improve drug deposition from DPIs. The particles were engineered by contacting spray-dried particles with a solvent in which these have a poor solubility. The process increased the particles hollow volume without affecting their original shape. The long TOF was demonstrated by carrier deposition in the lower stage of the TSI, which was up to 9 -fold higher compared to the conventional lactose. The highest deposition of the long TOF carrier was obtained at the lowest inhalation flow rate (24 L/min). The % Fine Particle Fraction of salbutamol sulphate was up to 50% when long TOF carrier was used. Importantly, this study has shown that adhesion drug/carrier has no negative effect on drug deposition, when a long TOF carrier is used

High-Resolution Ultrasound Spectroscopy for the Determination of Phospholipid Transitions in Liposomal Dispersions

High-resolution ultrasound spectroscopy (HR-US) is a spectroscopic technique using ultrasound waves at high frequencies to investigate the structural properties of dispersed materials. This technique is able to monitor the variation of ultrasound parameters (sound speed and attenuation) due to the interaction of ultrasound waves with samples as a function of temperature and concentration. Despite being employed for the characterization of several colloidal systems, there is a lack in the literature regarding the comparison between the potential of HR-US for the determination of phospholipid thermal transitions and that of other common techniques both for loaded or unloaded liposomes. Thermal transitions of liposomes composed of pure phospholipids (dimyristoylphosphatidylcholine, DMPC; dipalmitoylphosphatidylcholine, DPPC and distearoylphosphatidylcholine, DSPC), cholesterol and their mixtures were investigated by HR-US in comparison to the most commonly employed microcalorimetry (mDSC) and dynamic light scattering (DLS). Moreover, tramadol hydrochloride, caffeine or miconazole nitrate as model drugs were loaded in DPPC liposomes to study the effect of their incorporation on thermal properties of a phospholipid bilayer. HR-US provided the determination of phospholipid sol-gel transition temperatures from both attenuation and sound speed that are comparable to those calculated by mDSC and DLS techniques for all analysed liposomal dispersions, both loaded and unloaded. Therefore, HR-US is proposed here as an alternative technique to determine the transition temperature of phospholipid membrane in liposomes

Optimization of Solvent-Free Microwave-Assisted Hydrodiffusion and Gravity Extraction of Morus nigra L. Fruits Maximizing Polyphenols, Sugar Content, and Biological Activities Using Central Composite Design

Black mulberry, Morus nigra L. (family: Moraceae), is a healthy food and medicinal plant. Microwave hydrodiffusion and gravity (MHG) is one of the most innovative applications of solvent-free microwave extraction. The aim of this study was to optimize for the first time the MHG solvent-free extraction of polyphenols and sugars from M. nigra fruits. Optimization was carried out using a central composite design (CCD) with selected responses such as extraction yield, total polyphenol (TPC), flavonoid (TFC), anthocyanin (TAC), and sugar (TSC) contents, in addition to DPPH radical scavenging, and a-glucosidase (AGHi), lipase (Li), and xanthine oxidase (XOi) inhibition as tools to evaluate the best parameters for efficient and rapid extraction of black mulberry. The optimized extract was characterized in terms of the aforementioned parameters to validate the models, and was further analyzed for 36 individual polyphenols using HPLC-MS/MS. The optimized MHG extract was finally compared with traditional extracts, and demonstrated much better performance in terms of TPC, TAC, and Li, while the traditional extracts showed better XOi and AGHi. In conclusion, MHG is a valuable green technique for the production of non-degraded black mulberry polyphenol-rich extract and we suggest its larger use in the pharmaceutical and food industries

Sustainability of Urban Growth Forms in Metropolitan Area of Buenos Aires

Esta ponencia expone avances de una investigación cuyo objetivo es identificar indicadores de sustentabilidad urbana que contribuyan a evaluar el desempeño de distintas formas de crecimiento urbano y orientar la conformación de futuros observatorios que permitan monitorear el desempeño ambiental de unidades territoriales de análisis (UTA) dentro del AMBA. La metodología aplicada, basada en distintos autores que analizan la evolución del crecimiento urbano fue adaptada al contexto local y a los casos de estudio. Se seleccionaron cuatro unidades de análisis con diferente forma de crecimiento en dos municipios del AMBA. Se definieron variables para desarrollar indicadores, integrando sistemas de evaluación de sustentabilidad urbana y ambiental. Se relevaron las UTAs seleccionadas y realizaron ensayos bioclimáticos y mediciones in situ. Los resultados, permiten sacar las conclusiones comparativas iniciales del desempeño bioambiental de las unidades a fin de evaluar aspectos de sustentabilidad, tanto a escala de la unidad, como en relación al contexto urbano.This paper presents advances of a research that is aimed to identify urban sustainability indicators which help to evaluate the performance of various forms of city growth and guide the establishment of observatories for monitoring environmental performance of territorial units of analysis, transferable to different AMBA sectors. The methodology applied, based in different theories that interpret changes of urbanization in the cities, was adapted to local context. Four units of analysis of different growth form were selected in two municipalities in the AMBA. From the integration of different evaluation systems for urban sustainability, variables were defined to develop indicators. The selected units were analized and were made in situ environmental measurements. The results allows to obtain initial comparative conclusions about bioambiental performance of the units, aimed to evaluate some sustainability aspects both at the unit as in relation to urban context.Eje: Sustentabilidad urbana (Actas).Facultad de Arquitectura y Urbanism

Toxicological profiles and surface properties at physiological pH of N-decanoyl amino acids

Meeting title: From Food to Pharma: the polyhedral nature of polymersPURPOSE: N-acyl amino acids based surfactants are an attractive class of anionic amphiphiles alternative to sulphate-based surfactants potentially employed as excipients in all pharmaceutical applications at which an anionic surfactant (eg. sodium dodecyl sulphate SDS) is needed (1, 2). The aim of this work is to correlate surface properties of N-decanoyl amino acids at physiological pH and their toxicological profile in order to explore the potential use of these surfactants for …postprin

Evaluation of dibutyrylchitin as new excipient for sustained drug release

Dibutyrylchitin (DBC), a lipophilic chitin diester, has been synthesized from chitin and butyric anhydride with methanesulfonic acid as catalyst. Exhaustive esterification of free alcoholic groups of chitin was assessed by FT-IR and 1H-NMR spectroscopy. High degree of alkyl substitution allowed DBC to acquire an almost completely lipophilic character. Tablets of paracetamol and metformin employing DBC as major excipient, in comparison with starch, microcrystalline cellulose, lactose and polyvinylpyrrolidone, were prepared and rates of drug release were checked by dissolution test assays. DBC released drug at a lower rate than that of the other tested materials. A comparison study of rate release of metformin from DBC tablets and from metformin-hydroxypropyl methylcellulose prolonged release oral formulation available on the market has been also curried out. Under the same conditions and in the presence of the same amount of loaded drug, DBC released 64% of metformin whereas hypromellose-based tablets released 87%