Gaetano Lamberti

Measurement and modelling of the film casting process 1. Width distribution along draw direction

In the cast

Intensifying the microencapsulation process: ultrasonic atomization as an innovative approach.

lm process a polymer melt is extruded through a slit die, stretched in air and cooled on a chill roll. During the path in air, while the melt cools, a reduction of both thickness and width takes place; obviously, thickness and width reductions are functions of draw ratio and stretching distance. Width distribution along the draw direction was measured on a iPP resin supplied by Montell as function of both 8ow rate and take up velocity. Final

Measurement and modelling of the film casting process: 2. Temperature distribution along draw direction

lm width was found to decrease as take up velocity increase and, surprisingly, as extrusion 8ow rate increases. Thus draw ratio increase, attained by either lowering extrusion 8ow rate or by rising take up velocity, can lead to either enlargement or reduction of

Modeling the Drug Release from Hydrogel-Based Matrices

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Mathematical modeling of simultaneous drug release and in vivo absorption.

lm width. The process of stretching in air was modelled with coupled one-dimensional equations of continuity and motion based on work of Barq, Haudin, Agassant, and Bourgin (Int. Poly. Process. 9 (1994) 350) the crystallinity generation term, according to the Nakamura non-isothermal model, was included in the equation of energy lumped along the thickness direction. The polymer was considered as a viscous 8uid (non-Newtonian), the apparent viscosity being function of temperature and strain rate. Furthermore, the e?ect of crystallinity on viscosity was somehow accounted for. The model equations were solved numerically. A modi

Crystallinity and Linear Rheological Properties of Polymers

ed expression of heat transfer coe@cient with respect to the model of Barq et al. (1994) was applied leading to a better agreement between model predictions and data with reference to width distribution along the draw direction and

On the Behavior of HPMC/Theophylline Matrices for Controlled Drug Delivery

nal

A general code to predict the drug release kinetics from different shaped matrices.

lm thickness. ? 2001 Elsevier Science Ltd. All rights reserved.

Controlled drug release from hydrogel-based matrices: Experiments and modeling

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.

Liposomes as siRNA Delivery Vectors

Abstract In the case film process a polymer melt is extruded through a slit die, stretched in air and cooled on a chill roll. During the path in air the melt cools and a reduction of both thickness and width takes place; obviously, temperature distribution, thickness and width reductions are function of draw ratio and stretching distance. Temperature distribution along the draw direction was measured as function of flow rate during film casting experiments performed with an iPP resin. A non-contacting method of measurement, based on a narrow-band IR pyrometer, was adopted. A good qualitative agreement is shown between experimental temperature data and predictions of a model accounting of radiation emissivity dependence upon film thickness. Differences are consistent with discrepancies of film thickness evolution along draw direction, indeed the model slightly over predicts both film thickness reduction and, parallel, temperature decrease along the draw direction.