About

Gerardo Callegari is an Associate Research Professor in the Department of Chemical and Biochemical Engineering at Rutgers University. His areas of expertise include Pharmaceutical Manufacturing, Fluid Mechanics, and Mass Transport. He is located at the School of Engineering in Piscataway, NJ, and can be contacted via email at g.callegari@rutgers.edu. The information provided indicates his involvement in research related to chemical and biochemical engineering, with a focus on pharmaceutical processes and fluid dynamics.

Research topics

• Physics
• Data Mining
• Artificial Intelligence
• Mathematics
• Engineering
• Computer Science
• Biological system
• Composite material
• Mechanics
• Chemistry
• Materials science
• Mechanical engineering
• Geometry
• Process engineering

Selected publications

• Comparison of granules obtained with two twin-screw granulators of different diameter working at the same shear rate

  Powder Technology · 2025-05-02

  articleOpen accessSenior authorCorresponding

  We study the response of two twin-screw granulators of different barrel diameter to the variation of three process parameters (liquid-to-solid ratio, screw speed and throughput), while maintaining the same shear rate field along the screws. Various responses, including size distribution, porosity and content uniformity, were measured to determine granule characteristics. The set of experiments was based on a central composite design face-centered. Granules in both systems showed drug content consistent with expected values across varying process parameters. Relative granules size, normalized with the granulator gap, was larger for the equipment with the smaller gap. The liquid-to-solid ratio (LSR) was the most influential parameter affecting the granule size. Specifically, dimensional granule size increased with LSR values in both systems, consistent with previous studies. Elevated LSR values resulted in greater amounts of over-granulated material, whereas lower values produced exceedingly small (fines) or under-granulated material. The minimum amounts of both over- and under-granulated material were found at intermediate LSR values. Porosity varied differently between the systems, with a consistent reduction observed as LSR decreased from 0.3 to 0.4. Optimization studies revealed that central values of LSR and screw speed minimized fines and bigger granules while maximizing porosity, critical attributes for downstream processing. Granule size and porosity exhibited no significant correlation with tablet tensile strength across both systems. These findings offer valuable insights for optimizing pharmaceutical manufacturing processes to enhance product quality. • Granules produced at two twin screw granulators using a DoE were compared. • Ibuprofen content uniformity was consistent across both systems. • Moderate liquid-to-solid ratio maximizes porosity and usable granules. • Distinct granule properties observed, yet tablet tensile strength remains comparable.

  PublisherDOI

• Statistical data treatment for residence time distribution studies in pharmaceutical manufacturing

  International Journal of Pharmaceutics · 2024-04-19 · 3 citations

  article
  PublisherDOI

• Exploring pharmaceutical powder cohesion through the Warren Spring cohesion test

  Advanced Powder Technology · 2024-11-26

  article
  PublisherDOI

• CAPILLARY IMBIBITION TECHNIQUES USED TO CHARACTERIZE THESTRUCTURAL CHANGES IN MICROCRYSTALLINE CELLULOSE DUE TO WET AND DRY PROCESS

  Anales/Anales AFA · 2024-03-28

  articleOpen access

  In this work we study the change on the wettability and solid properties of microcrystalline cellulose (Avicel PH101)after it was wet and dried, through drop penetration experiments in slightly compacted porous beds. We perform these experiments with water and a silicone oil, (Polidimethilsyloxane–PDMS) and we determine a dimensionless parameter that takes into account all the water penetration factors, including wettability and swelling. We consider three different scenarios, original MCC, and after one and two wetting and drying cycles. For each case we study the particle size effects by considering two subset samples SiA)25<φ<75μm and SiB)75<φ<125μm. We were able to determine, as it was expected, that PDMS penetration dynamics is not affected by the wetting–drying cycles but water is. The penetration rate goes down after cellulose was wet. Finally we discuss how these behavior may affect the different processes where microcrystalline cellulose is used.

  PublisherOA PDFDOI

• Powder agglomeration in continuous powder feeding by twin-screw feeder

  Powder Technology · 2024-06-15 · 4 citations

  articleSenior authorCorresponding
  PublisherDOI

• High-dose modified-release formulation of a poorly soluble drug via twin-screw melt coating and granulation

  International Journal of Pharmaceutics · 2024-12-14 · 6 citations

  article
  PublisherDOI

• Water interaction with MCC powder exposed to wetting–drying cycles: Comparison of capillary imbibition techniques

  Powder Technology · 2024-09-17 · 2 citations

  articleOpen access
  PublisherOA PDFDOI

• Powder property change after passing through a feeder: The effect of electrostatics on powder flow

  Powder Technology · 2023 · 10 citations

  Senior authorCorresponding
  • Materials science
  • Mechanics
  • Composite material

  Powder feeding is one of the most critical processes in continuous manufacturing of powder-related products. Predictions of final product attributes have overlooked possible changes of powders properties as they pass through feeders and the effect has not been studied systematically. For example, the bulk density and the compressibility of the powder entering a continuous blender, have been assumed to be the same as the incoming raw materials. We find that this is not always the case. In this study, fourteen pharmaceutical powders were characterized both before and immediately after passing through a twin-screw feeder aiming to: (1) Quantitatively determine which materials alter their behavior. (2) Determine which properties are affected. (3) Investigate the probable causes of the changes in flow behavior (4) Validate the hypothesis that tribo-charging of the powder can be the cause of such behavior.

  PublisherDOI

• Optimal quantification of residence time distribution profiles from a quality assurance perspective

  International Journal of Pharmaceutics · 2023-01-28 · 8 citations

  article
  PublisherDOI

• Selection of an appropriate tracer to measure the residence time distribution (RTD) of continuous powder blending operations

  Powder Technology · 2023 · 15 citations

  • Computer Science
  • Data Mining
  • Process engineering
  PublisherDOI

Frequent coauthors

• Fernando J. Muzzio

  Rutgers, The State University of New Jersey

  22 shared

• Germán Drazer

  13 shared

• A. Calvo

  Universidad de Deusto

  12 shared

• Zhanjie Liu

  11 shared

• Jean‐Pierre Hulin

  Fluides, Automatique et Systèmes Thermiques

  11 shared

• Sonia M. Razavi

  9 shared

• F. Brochard‐Wyart

  Institut Curie

  9 shared

• Alberto M. Cuitiño

  7 shared