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Dr David Armitage

Job: Senior Lecturer in Pharmaceutical Technologies

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)116 257 7721

E: darmitage@dmu.ac.uk

W: https://www.dmu.ac.uk/hls

 

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Personal profile

Dr David Armitage is a Senior Lecturer in Pharmaceutical Technologies in the School of Pharmacy, De Montfort University. Following graduation from the University of Bristol with an honours degree in Physics and the University of Liverpool with a Masters degree in Materials Engineering he gained his PhD from the University of Nottingham.

He was awarded a prestigious Marie Curie Fellowship which enabled him to experience working for a medical device manufacturer in Belgium. Dr Armitage then undertook postdoctoral research at the School of Pharmacy, University of Nottingham and the Eastman Dental Institute, University College London. In 2007 he was appointed as Lecturer in Mechanics of Materials at Leicester University prior to taking his current post in 2008.

His current research interests are centred on application of surface modification and surface analytical techniques in the pharmaceutical and biomaterials sectors.He has researchinterests in the development of novel PAT tools for powder flow measurement.

He is admissions tutor for Pharmaceutical and Cosmetic Science (PCS) and teaches across PCS and the Pharmacy programme.

Research group affiliations

Pharmaceutical Technologies

Publications and outputs

  • A multi-faceted approach to determining the efficacy of metal and metal oxide nanoparticles against bacterial biofilms
    A multi-faceted approach to determining the efficacy of metal and metal oxide nanoparticles against bacterial biofilms Tejpal, Jyoti; Cross, R. B. M.; Owen, Lucy; Paul, Shashi; Jenkins, R. O.; Armitage, David; Laird, Katie Antibacterial efficacy of nanoscale silver, copper (II) oxide and zinc oxide were assessed against Pseudomonas aeruginosa and Staphylococcus aureus biofilms in solution and on surfaces. Using a Center for Disease Control biofilm reactor, minimum biofilm reduction concentrations, the coefficient of determination (R2) and log(10) reductions were determined. Atomic absorption spectroscopy, scanning electron microscopy and confocal laser scanning microscopy were used to assess the disruption of the biofilms. The efficacy of thin films of zinc oxide and silver deposited via magnetron sputtering and thermal evaporation respectively was also assessed. Minimum biofilm reduction concentrations of zinc oxide or silver nanoparticles were 256 or 50 µg/ml for P. aeruginosa and 16 or50 µg/ml for S. aureus respectively. When tested in combination the nanoparticles concentrations were at least halved resulting in significant (p ≤0.05) biofilm reductions of 3.77 log(10) - 3.91 log(10). Biofilm growth on thin films resulted in reductions of up to 1.82 log(10). The results suggest that nanoparticle suspensions and thin films of zinc oxide and may have potential as antimicrobial treatments for hard to eliminate biofilms in a clinical environment.
  • Development of aqueous ternary nanomatrix films: a novel ‘green’ strategy for the delivery of poorly soluble drugs
    Development of aqueous ternary nanomatrix films: a novel ‘green’ strategy for the delivery of poorly soluble drugs Kola-Mustapha, A.; Armitage, David; Abioye, A. O. Aqueous polymeric films have potentially great values in drug development, particularly in controlled drug release and taste masking strategies. However the progressive polymer-particle coalescence that occurs randomly during film formation, curing and storage may render the film less permeable leading to erratic and unpredictable drug release profile. The focus of this study was to investigate the impacts of the in situ formation of polymer-drug nanoconjugate, at the interfacial nano-domains of two oppositely charged polymers, on the mechanism of film formation and to prepare aqueous ternary polymer-drug-polymer nanomatrix films as a novel green strategy for the delivery of ibuprofen, a model poorly soluble drug. Composite and Layer-by-Layer films were prepared by aqueous casting technique using the concept of combined polymer-drug self-assembly and polyelectrolyte complexation. The plain and drug-loaded nanomatrix films were characterized using SEM, AFM, FTIR, DSC and TGA. Ibuprofen formed spherical core-shell microstructures (4.55 - 9.73 μm) in gellan film. However in the presence of cationic dextran (Ddex), nanoconjugates (61.49±5.97 - 447.52±37.51 nm) were formed within the core of the film matrix. The composite films exhibited reduced tensile strength and lower elastic modulus with optimal conjugation efficiency of 98.14±1.19%, which correlates with higher dissolution efficiency (99.76%) compared to 47.37% in layer-by-layer (LbL) films, dictated by Ddex concentration. Generally, the mechanism of drug release was by Fickian diffusion, however anomalous transport or polymer relaxation was also observed at higher concentration of Ddex. This study demonstrated the potential application of aqueous drug-loaded nanomatrix films as controlled drug delivery strategy for ibuprofen, a model poorly soluble drug.
  • Electrospun PVP-indomethacin constituents for transdermal dressings and drug delivery devices
    Electrospun PVP-indomethacin constituents for transdermal dressings and drug delivery devices Rasekh, M.; Karavasili, Chirstina; Soong, Yi Ling; Bouropoulos, Nikolaos; Morris, M. A.; Armitage, David; Li, Xiang; Fatouros, Dimitrios; Ahmad, Z. A method in layering dressings with a superficial active layer of sub-micrometer scaled fibrous structures is demonstrated. For this, polyvinylpyrolidone (PVP) - indomethacin (INDO) fibres (5% w/v PVP, 5% w/w indomethacin, using a 50:50 ethanol-methanol solvent system) were produced at different flow rates (50μL/min and 100μL/min) via a modified electrospinning device head (applied voltage varied between 15±2kV). We further assessed these structures for their chemical, physical and morphological properties using SEM, AFM, DSC, XRD, FTIR and HPLC-UV. The average diameter of the resulting 3D (∼500nm in height) PVP-INDO fibres produced at 50μL/min flow rate was 2.58±0.30μm, while the diameter almost doubled (5.22±0.83μm) when the flow rate was doubled. However, both of these diameters were appreciably smaller than the existing dressing fibres (∼30μm), which were visible even when layered with the active spun fibres. Indomethacin was incorporated in the amorphous state. The encapsulation efficiency was 75% w/w, with complete drug release in 45minutes. The advantages are the ease of fabrication and deposition onto any existing normal or functionalised dressing (retaining the original fabric functionality), elimination of topical product issues (application, storage and transport), rapid release of active and controlled loading of drug content (fibre layer). Electrospun PVP-indomethacin constituents for transdermal dressings and drug delivery devices.
  • Reduction of surface contamination and biofilms of Enterococcus sp and Staphylococcus aureus using a citrus-based vapour.
    Reduction of surface contamination and biofilms of Enterococcus sp and Staphylococcus aureus using a citrus-based vapour. Laird, Katie; Armitage, David; Phillips, C.
  • Nanoscale DNA tetrahedra improve biomolecular recognition on patterned surfaces.
    Nanoscale DNA tetrahedra improve biomolecular recognition on patterned surfaces. Schlapak, Robert; Danzberger, J.; Armitage, David; Morgan, D.; Ebner, Andreas; Hinterdorfer, Peter; Pollheimer, P.; Gruber, H. J.; Schaffler, F.; Howorka, Stefan
  • In vitro studies on the influence of surface modification of Ni-Ti alloy on human bone cells.
    In vitro studies on the influence of surface modification of Ni-Ti alloy on human bone cells. Chrzanowski, W.; Abou Neel, E.; Armitage, David; Zhao, X.; Knowles, J.; Salih, V.
  • Impaired bacterial attachment to light activated Ni–Ti alloy.
    Impaired bacterial attachment to light activated Ni–Ti alloy. Chrzanowski, W.; Valappil, S.; Dunnill, C.; Abou Neel, E.; Lee, Kevin; Parkin, I.; Wilson, M.; Armitage, David; Knowles, J.
  • A DNA nanostructure for the functional assembly of chemical groups with tunable stoichiometry and defined nanoscale geometry
    A DNA nanostructure for the functional assembly of chemical groups with tunable stoichiometry and defined nanoscale geometry Mitchell, Nick; Schlapak, Robert; Kastner, Markus; Armitage, David; Chrzanowski, W.; Riener, Johannes; Hinterdorfer, Peter; Ebner, Andreas; Howorka, Stefan
  • Semipermeable poly(ethylene glycol) films: the relationship between permeability and molecular structure of polymer chains
    Semipermeable poly(ethylene glycol) films: the relationship between permeability and molecular structure of polymer chains Schlapak, Robert; Armitage, David; Caruana, D.; Howorka, Stefan We describe size-selective semipermeable poly(ethylene glycol) (PEG) films which avoid the nonspecific absorption of large proteins but permit the passage of small target molecules. The size threshold for permeation through the PEG films on indium-tin oxide surfaces was characterised using cyclovoltammetry and redox-active probes of 0.3 and 0.6 nm diameter. The permeation was dependent on the molecular weight of PEG and the different conformational preferences of the polymer chains. PEG 5000 D with a looped and dynamically changing structure provided a porous and easily permeable meshwork for the passage of small molecules. In contrast, parallel aligned and helical PEG 500 chains represented a denser molecular sieve which is only permeable for small molecules 0.3 nm in size. By describing the relationship between the molecular structure and an important physiochemical property of surface-tethered PEG films, our findings on controllable semipermeable interfaces may be exploited for electrical sensor surfaces.
  • Selective protein and DNA adsorption on PLL-PEG films modulated by ionic strength.
    Selective protein and DNA adsorption on PLL-PEG films modulated by ionic strength. Schlapak, Robert; Armitage, David; Saucedo-Zeni, N.; Chrzanowski, W.; Caruana, D.; Howorka, Stefan; Hohage, M.

Click here for a full list of David Armitage's publications and outputs.

Research interests/expertise

  • Surface characterisation of modified surfaces in support of ultra sensitive biosensor applications.
  • Biocompatible materials.
  • Improved performance of orthopaedic implant materials through incorporation of metal ions into modified titanium surfaces.
  • Applications of zinc oxide based nanostructure for enhancing surface Plasmon resonance sensitivity in biosensor applications.
  • Surface Plasmon resonance imaging for rapid point of care medical diagnostics.
  • Characterisation and modification of surface properties of pharmaceutical materials.
  • Optical Process Analytical Technology Tools
  • Powder Flow Characterisation

Areas of teaching

Admissions Tutor:

  • B29041 Pharmaceutical and Cosmetic Science.

Module Leader:

  • PHAR1703 People and Medicines: GI and Nutrition
  • PHAR2604 Medicine Design and Development
  • PHCO1303 Pharmaceutical Processes and Technologies
  • PHCO3309 Pharmaceutical Materials Science
  • PHCO5303 Analytical Techniques in Materials Sciences.

I teach on the following modules on our Pharmacy undergraduate programme:

  • PHCO1505 Molecular Properties of Drugs
  • PHCO2505 Solid Dosage Forms: From Powder to Patient
  • PHCO3503 Pharmaceutics: From Solutions to Controlled Release.

I teach on the following modules on our Pharmaceutical and Cosmetic Science undergraduate programme:

  • PHCO1301 Compounding
  • PHCO2303 Process Technology 2
  • PHCO2311 Product Formulation
  • PHCO3302 Quality Assurance and Quality by Design Principles
  • PHCO3304 Project
  • PHCO3309 Pharmaceutical Materials Science (module leader)
  • PHCO3311 Development and Manufacture of Pharmaceutical Products
  • PHCO3313 New Approaches to Drug Delivery

I teach on the following modules on our Pharmaceutical Quality by Design M.Sc. postgraduate programme:

  • PHCO5301 Quality by Design
  • PHCO5303 Analytical Techniques in Materials Sciences (module leader)
  • PHCO5306 Process Analytical Technology and Chemometrics
  • PHCO5307 Advances in Drug Delivery

Conference attendance

2008 British Pharmaceutical Congress, Manchester, Calcium Enriched Titanium Surfaces via a Hydrothermal Process, D.A. Armitage, R.I. Mihoc, F.H. Jones, T.J. Tate & J.C. Knowles.

2009 British Pharmaceutical Congress, Manchester, Therapeutic Ion Release from Modified Titanium Surfaces,D. A. Armitage, F.H. Jones & J.C. Knowles.

Current research students

  • Kennedy Omonalia (1st Supervisor)
  • Nare Gabrielin, (2nd Supervisor)