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Professor Geoff Smith

Job: Professor of Pharmaceutical Process Analytical Technology

Faculty: Health and Life Sciences

School/department: Leicester School of Pharmacy

Research group(s): Pharmaceutical Technologies

Address: De Montfort University, The Gateway, Leicester, LE1 9BH.

T: +44 (0)116 250 6298

E: gsmith02@dmu.ac.uk

W: www.dmu.ac.uk/pharmaceutical

Social Media: uk.linkedin.com/in/gsmith02

 

Personal profile

Geoff Smith graduated in Pharmacy from the University of Bath in 1985 and obtained his PhD from the University of Brighton in 1991 based on a study of the mechanisms of action of cryoprotectants. It was then that he developed a keen interest in the dielectric properties of materials.

He joined De Montfort University in 1993 and went on to develop a number of lines of research based around broad band dielectric measurements. In recent years these studies are focussed increasingly on PAT applications in process development and manufacturing controls for the pharmaceutical industry. His research group is now working on a number of pharmaceutical applications for impedance, dielectric and terahertz spectroscopy alongside optical techniques such as laser speckle and optical flow. These techniques cover an extremely wide range of frequencies thereby enabling the direct analysis of material properties over a wide range of scales from the macroscopic to the molecular.

He was responsible for the development of through-vial impedance spectroscopy (LyoDEA) as a PAT tool for monitoring phase behaviour (ice formation and eutectics), temperatures, and drying profiles and end points, in collaboration with GEA Pharma Systems and AstraZeneca (Funded by the Technology Strategy Board).

More recently his pharmaceutical research focus has extended to investigations into the use of electrostatic noise measurements and optical imaging for applications in roller compaction, powder flow and tablet defect analysis, with the aim of improving understanding and control of tablet production methods.

From 2007 he began to re-structure the Pharmaceutical Technologies group, by recruiting staff from various backgrounds, including chemists, physicists, chemical engineers and process control specialists in order to diversify the research base of the group and to re-focus efforts on current pharmaceutical industry challenges in product design and manufacturing. By 2010 he had instigated De Montfort University's Pharmaceutical Quality by Design programme, with a wide range of industrial practitioners providing webinars on elements of quality by design.

 

Research group affiliations

Pharmaceutical Technologies 

Publications and outputs 

  • Determination of ice interface temperature, sublimation rate and the dried product resistance, and its application in the assessment of microcollapse using through-vial impedance spectroscopy
    Determination of ice interface temperature, sublimation rate and the dried product resistance, and its application in the assessment of microcollapse using through-vial impedance spectroscopy Smith, Geoff; Jeeraruangrattana, Yowwares; Polygalov, E.; Ermolina, I. Through-vial impedance spectroscopy (TVIS) is a new approach for characterizing product attributes during freeze-drying process development. In this study, a pair of copper foil electrodes was attached to the external surface of a Type I glass tubing vial, of nominal capacity 10 mL and containing 3.5 g of an aqueous solution of 5% w/v lactose, and the impedance spectrum of the vial and contents recorded during a lyophilization cycle. The cycle included a temperature ramp in the primary drying stage in order to induce a collapse event in the dry layer. Using the peak in the dielectric loss spectrum, associated with the dielectric relaxation of ice, methods were developed to predict the sublimation rate and the ice interface temperature at the sublimation front, from which the dry layer resistance was then calculated. A four-fold increase in sublimation rate and a reduction in the dry layer resistance wereobserved once the ice interface temperature reached −33 °C, which coincides with the onset of the glass transition (as determined by DSC) and the time point at which micro-collapse occurred (as evidenced by SEM images at the end of the cycle). This work suggests a prospective application of impedance measurements in driving process efficiencies by operating the dryer at the highest achievable temperature (i.e. the collapse temperature) whilst avoiding macro-collapse. The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.
  • An investigation on a quantum communication phenomenon between sub-atomic properties of substances by Quantum eraser pattern quantification
    An investigation on a quantum communication phenomenon between sub-atomic properties of substances by Quantum eraser pattern quantification Orun, A.; Smith, Geoff The proposed novel idea is concerned with the investigation on a probability of sub-atomic quantum communication between the chemical substances by use of “interferometric Quantum eraser” pattern analysis, which would be the first step towards the further comprehensive study on a similar natural communications between the medications and diseased organic tissues. The hypothesis is based on the idea that, sub-atomic particles like photons attempt to access or gain complementary information causing their “wave-particle duality” shifting which is used to observe their time-sequenced activities. Such information would probably be provided by sub-atomic quantum communication action demonstrated between the substances in a chemical reaction. Similarly, the medications may have curing effects on a diseased organic tissue after such “natural” communication, by which a complementary information is transferred from the sub-atomic properties of chemical substance to the diseased organic tissue at same level for the treatment. The file attached to this record is the author's final peer reviewed version.
  • Through-Vial Impedance Spectroscopy (TVIS): A New Method for Determining the Ice Nucleation Temperature and the Solidification End Point
    Through-Vial Impedance Spectroscopy (TVIS): A New Method for Determining the Ice Nucleation Temperature and the Solidification End Point Smith, Geoff; Jeeraruangrattana, Yowwares The file attached to this record is the author's final peer reviewed version.
  • The use of through vial impedance spectroscopy (TVIS) for determination of ice nucleation, solidification end point, and mannitol crystallization during freezing and re-heating
    The use of through vial impedance spectroscopy (TVIS) for determination of ice nucleation, solidification end point, and mannitol crystallization during freezing and re-heating Ogugua, Longinus; Smith, Geoff; Orun, A. This is a study of the freezing/reheating behavior of aqueous solutions of mannitol with respect to lyophilization process development given the prevalent use of the excipient. Here, through-vial impedance spectroscopy (TVIS) was used to study the thermophysical kinetics of an aqueous solution of 5%w/v mannitol during a freezing and re-heating phase of a freeze-drying cycle. Temperature calibration of the TVIS parameter FPEAK enabled the determination of the ice nucleation temperature Tn at −13 oC while the ice solidification end point was observed based on the time profile of C' (0.2MHz), i.e. the real part capacitance at 0.2 MHz. A time difference of 20 min between the onset and end point then defines the ice solidification time ti. A later step in C' (0.2MHz) indicated that mannitol crystallized at -32 oC and 20 minutes from end of ice solidification. Upon reheating at 0.2 oC/min, a large increase in C' (0.2MHz) was seen at −32 oC indicating the onset of melting of mannitol crystals which then lasted 20 min.
  • Through vial impedance spectroscopy (TVIS): A novel approach to process understanding for freeze-drying cycle development
    Through vial impedance spectroscopy (TVIS): A novel approach to process understanding for freeze-drying cycle development Smith, Geoff; Polygalov, Evgeny Through vial impedance spectroscopy (TVIS) provides a new process analytical technology for monitoring a development scale lyophilization process, which exploits the changes in the bulk electrical properties that occur on freezing and subsequent drying of a drug solution. Unlike the majority of uses of impedance spectroscopy, for freeze-drying process development, the electrodes do not contact the product but are attached to the outside of the glass vial which is used to contain the product to provide a non-sample-invasive monitoring technology. Impedance spectra (in frequency range 10 Hz to 1 MHz) are generated throughout the drying cycle by a specially designed impedance spectrometer based on a 1 GΩ trans-impedance amplifier and then displayed in terms of complex capacitance. Typical capacitance spectra have one or two peaks in the imaginary capacitance (i.e., the dielectric loss) and the same number of steps in the real part capacitance (i.e., the dielectric permittivity). This chapter explores the underlying mechanisms that are responsible for these dielectric processes, i.e., the Maxwell-Wagner (space charge) polarization of the glass wall of the vial through the contents of the vial when in the liquid state, and the dielectric relaxation of ice when in the frozen state. In future work, it will be demonstrated how to measure product temperature and drying rates within single vials and multiple (clusters) of vials, from which other critical process parameters, such as heat transfer coefficient and dry layer resistance, may be determined. The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.
  • Correlation between molecular dynamics and physical stability of two milled anhydrous sugars: lactose and sucrose
    Correlation between molecular dynamics and physical stability of two milled anhydrous sugars: lactose and sucrose Smith, Geoff; Hussain, Amjad; Bukhari, Nadeem Irfan; Ermolina, I. The process of milling often results in amorphization and the physical stability of amorphous phase is linked with its molecular dynamics. This study focuses on a propensity of two disaccharides (lactose and sucrose) to amorphize on ball milling and the stability of the resultant amorphous phase. The amorphous content in milled sugars is estimated by Differential Scanning Calorimetry (DSC) and the stability was measured in terms of the tendency to recrystallize by Broadband Dielectric Spectroscopy (BDS). The results show that the amorphous content increases with milling time and is greater for lactose than sucrose. At the same degree of amorphization, sucrose recrystallize at temperature ∼15 °C higher than lactose, indicating higher stability. The molecular dynamics (beta relaxation process), suggest that milled sucrose is more stable with higher activation energy (∼9 kJ mol−1) than that of lactose. The moisture content of amorphous phase also impacts its molecular dynamics in terms of increase in activation energy as the moisture decrease with increasing the milling times. The study suggests a greater stability of amorphous sucrose and susceptibility of milled lactose to recrystallize, however, on extended milling when the moisture content decreases, lactose was seen to become relatively more stable. The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.
  • Solubility and dissolution rate enhancement of ibuprofen by co-milling with polymeric excipients
    Solubility and dissolution rate enhancement of ibuprofen by co-milling with polymeric excipients Smith, Geoff; Pedge, Nicholas; Khan, Karrar A; Bukhari, Nadeem Irfan; Hussain, Amjad; Ermolina, I. The aim of this study was to enhance the kinetic solubility and dissolution rate of ibuprofen by co-milling with different excipients and to establish the underlying mechanism(s) for such enhancement. In the first-part, two excipients (HPMC and soluplus) were selected from seven, and the optimal ball-milling parameters of speed and time (18 Hz, 15 min) were determined based on solubility-enhancement and flow-ability criteria. In the second-part, co-milling of different weight-ratios of ibuprofen-to-excipient was carried out and solubility and dissolution rates were determined. Mechanisms of biopharmaceutical enhancement were studied by SEM, laser diffraction, DSC, and FTIR analysis of the co-mixtures. Ibuprofen solubility (0.09 mg/mL for un-milled) was increased by factors of 4–5 and 10–20 for HPMC and soluplus, respectively. The weakening of crystals, stabilization of the amorphous phase and an increase in solid-state hydrogen bonding are the likely mechanisms for this enhancement. Reductions in Q70% dissolution time were also observed, by a factor of 4 and 7 for ibuprofen:HMPC and ibuprofen:soluplus co-milled mixtures, respectively. Although, there were similar reductions in particle size, dispersibility and degree of amorphization in both mixtures, the higher dissolution rate for soluplus, over that for HPMC, must be due to the additional solubilization contribution to the kinetic solubility provided by soluplus. The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.
  • Effect of Arginine on the Aggregation of Protein in Freeze-Dried Formulations Containing Sugars and Polyol: II. BSA Reconstitution and Aggregation
    Effect of Arginine on the Aggregation of Protein in Freeze-Dried Formulations Containing Sugars and Polyol: II. BSA Reconstitution and Aggregation Hackl, E. V.; Darkwah, Joseph; Smith, Geoff; Ermolina, I. The current paper continues our study on the ability of L-arginine to prevent/reduce the aggregation of proteins that results from the various stresses during the lyophilisation and/or storage of lyophilized protein-based products. The first part of our study, i.e. formulation development, was devoted to the rational design and optimization of an L-arginine containing lyophilized formulation which can resist the natural tendency of L-arginine to absorb atmosphere moisture. Mannitol and trehalose were chosen among other excipients to be included in the protein-based formulation, as mannitol in a combination with L-arginine has been shown to reduce moisture sorption while trehalose provides a degree of lyoprotection. In the present study, a number of formulations, which comprised bovine serum albumin (BSA) with and without L-arginine, and with five different ratios of trehalose-to-mannitol (from 30:70 to 80:20) were lyophilised and assessed. The internal structures and the moisture sorption/retention of the lyophilized formulations were characterised. To study the effect of L-arginine on BSA solid-phase stability, the lyophilized powder was exposed to accelerated storage conditions (high moisture (75% RH) and temperature (22 or 45 °C)) for up to 24 h. The lyophilized BSA formulations were then reconstituted and solution-state protein aggregation assessed by turbidimetry at 360 nm and fluorescence spectroscopy using the thioflavin T assay. It was demonstrated that L-arginine can be used in protein-based freeze-dried formulations to significantly reduce the aggregation of protein during the manufacturing, storage and subsequent reconstitution. The results also revealed the importance of a sufficient amount of mannitol in the arginine-containing formulations. The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.
  • The application of dual-electrode through vial impedance spectroscopy for the determination of ice interface temperatures, primary drying rate and vial heat transfer coefficient in lyophilization process development
    The application of dual-electrode through vial impedance spectroscopy for the determination of ice interface temperatures, primary drying rate and vial heat transfer coefficient in lyophilization process development Smith, Geoff; Jeeraruangrattana, Yowwares; Ermolina, I. Through vial impedance spectroscopy (TVIS) is a product non-invasive process analytical technology which exploits the frequency dependence of the complex impedance spectrum of a composite object (i.e. the freeze-drying vial and its contents) in order to track the progression of the freeze-drying cycle. This work demonstrates the use of a dual electrode system, attached to the external surface of a type I glass tubing vial (nominal capacity 10 mL) in the prediction of (i) the ice interface temperatures at the sublimation front and at the base of the vial, and (ii) the primary drying rate. A value for the heat transfer coefficient (for a chamber pressure of 270 µbar) was then calculated from these parameters and shown to be comparable to that published by Tchessalov (2017). The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.
  • Effect of arginine on the aggregation of protein in freeze-dried formulations containing sugars and polyol. 1. Formulation development
    Effect of arginine on the aggregation of protein in freeze-dried formulations containing sugars and polyol. 1. Formulation development Hackl, E. V.; Darkwah, Joseph; Smith, Geoff; Ermolina, I. L-arginine was introduced into protein-based freeze-dried formulations to study the ability of arginine to reduce / prevent from protein aggregation during manufacturing, storage and reconstitution of lyophilized protein-based pharmaceuticals. As L-arginine is known to be very hygroscopic, additional excipients which could provide a moisture buffering capacity need to be introduced into the formulation. In the first part of our study – excipient formulation development – the screening of a number of sugars/polyols has been done in order to select the best combination of excipients that, in a complex with L-arginine, can i) produce freeze-dried cakes with elegant appearance, adequate mechanical properties and reconstitution times, and ii) resist/minimize the moisture sorption. Various freeze-dried cakes containing L-arginine in combination with mannitol, trehalose, lactose, and sucrose were produced and analyzed by TGA, DSC, texture analysis, moisture sorption, cake shrinkage, TVIM and SEM. The non-linear dependencies of the physicochemical properties of the freeze-dried cakes on the sugar-to-mannitol ratios were found. The best combinations of excipients (L-arginine, mannitol and trehalose) were selected to be used in the second part of this work, in which the impact of each selected formulation will be studied in relation to the aggregation of a protein. The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.

Click here for a full list of Geoff Smith's publications and outputs.

Key research outputs

Smith, G., Arshad, M.S., Polygalov, E., Ermolina, I., McCoy, T.R., Matejtschuk, P. (2017). Process Understanding in Freeze-Drying Cycle Development: Applications for Through-Vial Impedance Spectroscopy (TVIS) in Mini-pilot Studies. Journal of Pharmaceutical Innovation, 12 (1), pp. 26-40

Arshad, M.S., Smith, G., Polygalov, E., Ermolina, I. (2014). Through-vial impedance spectroscopy of critical events during the freezing stage of the lyophilization cycle: The example of the impact of sucrose on the crystallization of mannitol. European Journal of Pharmaceutics and Biopharmaceutics, 87 (3), pp. 598-605

Smith, G., Polygalov, E., Arshad, M.S., Page, T., Taylor, J., Ermolina, I. (2013) An impedance-based process analytical technology for monitoring the lyophilisation process. International Journal of Pharmaceutics, 449 (1-2), pp. 72-83

Smith, G., Arshad, M.A., Polygalov, E., Irina Ermolina, I. (2013) Factors Affecting the Use of Impedance Spectroscopy in the Characterisation of the Freezing Stage of the Lyophilisation Process: the Impact of Liquid Fill Height in Relation to Electrode Geometry. AAPS PharmSciTech, online first

Smith, G., Arshad, M.S., Polygalov, E. and Ermolina, I. (2013) An application for impedance spectroscopy in the characterisation of the glass transition during the lyophilization cycle: The example of a 10% w/v maltodextrin solution. European Journal of Pharmaceutics and Biopharmaceutics, 86 (3 Part B), pp. 1130-1140

Smith, G., Polygalov, E. & Page, T. (2011) A method for monitoring and/or controlling process parameters of a lyophilisation process. British patent application 2480299. Application Number 1007961.4. Filing date 12.05.2010

Research interests/expertise

  • Freeze-drying process development
  • Process analytical technologies (novel sensors in process understanding and control)
  • Impedance spectroscopy, dielectric spectroscopy, terahertz spectroscopy and terahertz imaging, dynamic laser speckle, electrostatic measuremnst of powder flow
  • See current PhD projects for more information.

Areas of teaching

  • Pharmaceutical Sciences
  • Good Manufacturing Practice
  • Pharmaceutical Quality by Design
  • Freeze-Drying
  • Preformulation

Qualifications

  • PhD. Mechanims of Action of Cryoprotectant 1991
  • BPharm 1985 University of Bath

Courses taught

  • BSc Pharmaceutical and Cosmetic Sciences
  • MSc Pharmaceutical Quality by Design

Membership of external committees

 

Membership of professional associations and societies

 

Forthcoming events

 

Conference attendance

Smith   G. (2018) Through-Vial Impedance Spectroscopy (TVIS). A new process   analytical technology for freeze-drying process development. Podium   presentation at: SMi 6th Annual Conference on Pharmaceutical Freeze-Drying   Technology, 2018 June 13-14th, Holiday Inn Kensington Forum, London, United   Kingdom 
Smith G. (2018) Through-Vial Impedance Spectroscopy (TVIS). A   Novel Process Analytical Technology for the Development of Pharmaceutical   Products and Processes.Podium presentation at 2nd Annual Lyophilization   Summit, Vienna, Austria, May 24-25th 2018
Smith   G. (2018) Through Vial Impedance Spectroscopy (TVIS): Dual-Electrode System   for Process Parameter Determination. Podium presentation at  ISL-FD Midwest Chapter Annual Meeting,   Midwest Conference Centre, Northlake, IL 60164, USA, April 12th 2018
Smith   G. Through Vial Impedance Spectroscopy (TVIS): A Novel Approach in the   Development of Freeze-Drying Processes for Drug Products. Podium presentation   at 10th International Workshop on Impedance Spectroscopy, 2017 September   27-29, Chemnitz, Germany
Smith,   G. (2017) Recent Advances in Through Vial Impedance Spectroscopy (TVIS) for   Process Parameter Determination. ISL-FD Conference April 26-28th 2017.   Havana, Cuba
Smith,   G. (2017) Applications for Through Vial Impedance Spectroscopy (TVIS) in   Process Parameter Determination. LyoTalk Dublin, May 22 2017
Smith, G. (2016)  The   Application of Through Vial Impedance Spectroscopy (TVIS)  for Process Parameter Determination in   Freeze-Drying Method Development. PDA Europe. Pharmaceutical Freeze Drying   Technology. Strasbourg, 27 – 28 September 2016
Smith, G. (2016) Through Vial Impedance Spectroscopy. SMi   Lyophilisation Europe, Kensington, London, United Kingdom 4-5 July 2016
Smith, G. (2015) Process Analytical Technology and the Question   of Scale. ISL-FD 2015 International Society of Lyophilization – Freeze Drying   Conference and Seminar. College of Pharmacy, Barcelona, 8-10 July 2015
Smith, G. (2015) A focus on PAT in freeze-drying. APS Parenteral   Focus Group meeting on Freeze Drying and Alternative Drying Technologies for   Parenterals, Burleigh Court, Loughborough University.28 January 2015

Consultancy work

We currently offer our expertise in freeze-drying process development to assist pharmaceutical companies in the development of optimized freeze-drying cycles. Through the application of new process analytical technologies (LyoDEA) we can reduce your development time while delivering a shorter cycle time.

This will reduce the materials consumed in development, accelerate your product to market, and provide you with a more efficient process hence reduce the cost of manufacture.

Externally funded research grants information

EXTALcoat : External Lubrication Coating Inspection System by Dynamic Laser Speckle Imaging (grant ref. 132872)

£115,054 Feasibility Study

March 1 2018 to  February 28 2019

Funding body : Innovate UK

Partners: Gasfill Ltd (Micron Design), Nutrapharma, Merlin Powder Characterization, S3 Process, De Montfort University

 

FastLyo (grant ref. 133425)

£99,849 Feasibility Study

March 1 2018 to  February 28 2019

Funding body : Innovate UK

Partners: Biopharma Process Solutions, OnkoLytika, De Montfort University

 

AtlasBio (grant ref. 102610)

£803 846 Collaborative R&D

February 1 2017 to  January 31 2020

Funding body : Innovate UK

Partners: GEA, BlueFrog, CPI, 

OnkoLytika, IS Instruments, Ocean Optics,

National Institute for Biological Standards and Control, Nottingham University, De Montfort University

 

BioStaRT (grant ref. 101711)

£367 567 Collaborative R&D

August 1 2014 to Jan 31 2018

Funding body : Innovate UK

Partners: GEA, BlueFrog, Sanofi (Ireland)

National Institute for Biological Standards and Control, De Montfort University    

 

LyoDEA (grant ref. 100527)

£217 160 Collaborative R&D

November 1 2008 to October 31  2012

Funding body : Technology Strategy Board

Partners: GEA, AstraZeneca, Ametek, De Montfort University

Published patents

Smith, G, and Polygalov E. (2007). Apparatus for measuring the dielectric properties of conductive materials. British patent 0704880.4 Filing date 13 March 2007. Publication number GB2447477 17 September 2008

Smith, G., Polygalov, E. and Page, T. (2011) A method for monitoring and/or controlling process parameters of a lyophilisation process. GB patent GB2480299 (A). Application number GB20100007961 20100512. Priority date 12 May 2010. Published 16th November 2011

TVIS : Through Vial Impedanace Spectroscopy

The freeze-drying cycle comprise three stages, of pre-freezing (to form ice and to crystallise out any solutes with a propensity to crystallise), primary drying to remove the ice phase, and secondary drying to remove the water which is physic-sorbed to the remaining matrix or crystalline and amorphous solids. Process optimization and scale up requires measurement technologies for characterising each stage of the process. In the freezing stage, it is essential to maximise the amount of ice that forms and to optimise the ice structure in order to facilitate sublimation in the primary drying phase. In primary drying it is essential that the product temperature is as high to reduce the drying time, while maintaining it below certain critical temperatures (e.g. eutectic temperature if the unfrozen phase is largely crystalline and the glass transition if the unfrozen phase is largely amorphous) in order to avoid collapse (from melting and/or loss of structural viscosity.

Process analytical techniques for achieving these challenges goals are limited. Thermocouples are used primary for the detection of crystallization (primary phase transitions) but are ineffective at detecting the glass transition and collapse. Pressure rise testing is used in primary drying, and through modelling of the system can be used to control the temperature at the sublimation interface, and hence optimise the drying process. However, the thermocouple is invasive and may itself alter the ice crystal structure (and hence drying profile), whereas the pressure rise testing model relies on many assumptions in the model which provides an average batch measurement across the drier, and only works in the early phase of drying when there is a steady state condition.

The Pharmaceutical Technologies Group has developed a new approach for process understanding for freeze-drying cycle development, which uses a through vial impedance measurement (TVIS) to characterise a broad range of features of the process, including, ice onset times, the completion of ice solidification, the glass transition, and the structural relaxation of the unfrozen solid, and the primary drying rate and end point. The on-going development of this technology will see the application with micro-titre plate technologies for formulation screening (micro-scale down) and for scale up into production by using a non-contact probes for monitoring problematic regions within the drier.

 Key References

Arshad, M.S. Smith, G., Polygalov, E., Ermolina, I. (2014). Through-vial impedance spectroscopy of critical events during the freezing stage of the lyophilization cycle: The example of the impact of sucrose on the crystallization of mannitol. Eur J Pharm Biopharm., 87, (3), pp. 598-605

Smith, G.; Arshad, Muhammad Sohail; Polygalov, E., Ermolina, I. (2014). Through-Vial Impedance Spectroscopy of the Mechanisms of Annealing in the Freeze-Drying of Maltodextrin: The Impact of Annealing Hold Time and Temperature on the Primary Drying Rate. J Pharm. Sci., 103, (6), 1799-1810

Smith, G., Arshad, M.A., Polygalov, E., Ermolina, I. (2013) Factors Affecting the Use of Impedance Spectroscopy in the Characterisation of the Freezing Stage of the Lyophilisation Process: the Impact of Liquid Fill Height in Relation to Electrode Geometry. AAPS PharmSciTech, online first

Smith, G., Arshad, M.S., Polygalov, E. and Ermolina, I. (2013) An application for impedance spectroscopy in the characterisation of the glass transition during the lyophilization cycle: The example of a 10% w/v maltodextrin solution. European Journal of Pharmaceutics and Biopharmaceutics, 86 (3 Part B), pp. 1130-1140

Smith, G., Polygalov, E., Arshad, M.S., Page, T., Taylor, J., Ermolina, I.  (2013) An impedance-based process analytical technology for monitoring the lyophilisation process. International Journal of Pharmaceutics, 449 (1-2), pp. 72-83

Smith, G., Arshad, M.S., Polygalov, E. and Ermolina, I. (2013) An application for impedance spectroscopy in the characterisation of the glass transition during the lyophilization cycle: The example of a 10% w/v maltodextrin solution. European Journal of Pharmaceutics and Biopharmaceutics, 86 (3 Part B), pp. 1130-1140

Smith, G., Polygalov, E. & Page, T. (2011) A method for monitoring and/or controlling process parameters of a lyophilisation process. British patent application 2480299. Application Number 1007961.4. Filing date 12.05.2010

 

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