Associate Professor Greg Walker

Contact Details
- Phone
- +64 3 479 7133
- greg.walker@otago.ac.nz
University Links
- Position
- Associate Professor Head of the Bayer Centre for Dairy Animal Health / Pharmaceutical Science and Product Innovations at the School of Pharmacy (2019-present)
- Qualifications
- BSc MSc PhD(Otago)
- Research summary
- Drug delivery and formulation
- Teaching
- PHCY211: Fundamental Pharmaceutical Sciences (Dosage forms module coordinator)
- PHCY220: Integrated modules A
- PHCY430: Elective Projects B
- PHCY485: Honours
- Memberships
- Controlled Release Society (2012-present)
- New Zealand Chapter of the Controlled Release Society (2012 to present): President of the Society (November 2017 to present)
Research
Associate Professor Walker’s general area of research interest is in formulation and delivery of bioactive molecules. Particular interests are in physico-chemical principles relating to how delivery systems can influence the absorption, disposition and fate of bioactives in the body and how such systems can increase the efficacy of bioactives.
He has extensive experience in polymeric drug delivery systems, engineering formulations for biopharmaceuticals, project management and pre-clinical studies.
Prior to joining University of Otago as a lecturer, he was the Research and Development Manager at a UK biotech company where he invented the lead technology of a new class of topical haemostat (PeproStat) which has completed successful phase two clinical trials.
As head of the Bayer Centre for Dairy Animal Health / Pharmaceutical Science and Product Innovations at the School of Pharmacy, he applies his formulation and drug delivery expertise to issues relating to veterinary and animal health.
Associate Professor Walker is a key researcher in three Ministry of Business, Innovation and Employment (MBIE) grants totalling to over NZ $19 million. These projects focus on the formulation and delivery of: vaccines, a new class of antimicrobials and bioactives to crops.
PhD projects are available, please contact me if you are interested in conducting PhD research in the field of formulation and drug delivery.
Publications
Nguyen, H. V., Campbell, K., Painter, G. F., Young, S. L., & Walker, G. F. (2022). Effect of carrier molecular weight on physicochemical properties and the in vitro immune-stimulatory activity of the CpG-dextran conjugates. International Journal of Pharmaceutics, 627, 122236. doi: 10.1016/j.ijpharm.2022.122236
Liu, W., Price, S., Bennett, G., Maxwell, T. M. R., Zhao, C., Walker, G., & Bunt, C. (2022). A landscape review of controlled release urea products: Patent objective, formulation and technology. Journal of Controlled Release, 348, 612-630. doi: 10.1016/j.jconrel.2022.06.009
McLaughlin, A. W., McDowell, A., Clarkson, A. N., & Walker, G. F. (2022). Characterization of poly(lactic-co-glycolic acid) nanofibers electrospun using a sustainable green chemistry with a low toxicity solvent system. International Journal of Polymeric Materials & Polymeric Biomaterials, 71(13), 983-992. doi: 10.1080/00914037.2021.1933976
Bērziņš, K., Fraser-Miller, S. J., Walker, G. F., Rades, T., & Gordon, K. C. (2021). Investigation on formulation strategies to mitigate compression-induced destabilization in supersaturated celecoxib amorphous solid dispersions. Molecular Pharmaceutics, 18, 3882-3893. doi: 10.1021/acs.molpharmaceut.1c00540
Liu, W., Walker, G., Price, S., Yang, X., Li, J., & Bunt, C. (2021). Electrospun membranes as a porous barrier for molecular transport: membrane characterization and release assessment. Pharmaceutics, 13(6), 916. doi: 10.3390/pharmaceutics13060916
McLaughlin, A. W., McDowell, A., Clarkson, A. N., & Walker, G. F. (2022). Characterization of poly(lactic-co-glycolic acid) nanofibers electrospun using a sustainable green chemistry with a low toxicity solvent system. International Journal of Polymeric Materials & Polymeric Biomaterials, 71(13), 983-992. doi: 10.1080/00914037.2021.1933976
Journal - Research Article
Nguyen, H. V., Campbell, K., Painter, G. F., Young, S. L., & Walker, G. F. (2022). Effect of carrier molecular weight on physicochemical properties and the in vitro immune-stimulatory activity of the CpG-dextran conjugates. International Journal of Pharmaceutics, 627, 122236. doi: 10.1016/j.ijpharm.2022.122236
Journal - Research Article
Bērziņš, K., Fraser-Miller, S. J., Walker, G. F., Rades, T., & Gordon, K. C. (2021). Investigation on formulation strategies to mitigate compression-induced destabilization in supersaturated celecoxib amorphous solid dispersions. Molecular Pharmaceutics, 18, 3882-3893. doi: 10.1021/acs.molpharmaceut.1c00540
Journal - Research Article
Campbell, K., Young, V. L., Donaldson, B. C., Woodall, M. J., Shields, N. J., Walker, G. F., Ward, V. K., & Young, S. L. (2021). Delivering two tumour antigens survivin and mucin-1 on virus-like particles enhances anti-tumour immune responses. Vaccines, 9(5), 463. doi: 10.3390/vaccines9050463
Journal - Research Article
Davison, E. K., McGowan, J. E., Li, F. F., Harper, A. D., Young Jeong, J., Mros, S., Harbison-Price, N., Van Zuylen, E. M., Knottenbelt, M. K., Heikal, A., Ferguson, S. A., McConnell, M. A., Cook, G. M., Krittaphol, W., Walker, G. F., … Rennison, D. (2021). C-2 derivatized 8-sulfonamidoquinolines as antibacterial compounds. Bioorganic & Medicinal Chemistry, 29, 115837. doi: 10.1016/j.bmc.2020.115837
Journal - Research Article
Dowlath, S., Campbell, K., Al-Barwani, F., Young, V. L., Young, S. L., Walker, G. F., & Ward, V. K. (2021). Dry formulation of virus-like particles in electrospun nanofibers. Vaccines, 9(3), 213. doi: 10.3390/vaccines9030213
Journal - Research Article
Liu, W., Walker, G., Price, S., Yang, X., Li, J., & Bunt, C. (2021). Electrospun membranes as a porous barrier for molecular transport: membrane characterization and release assessment. Pharmaceutics, 13(6), 916. doi: 10.3390/pharmaceutics13060916
Journal - Research Article
McGowan, J. E., Harper, A. D., Davison, E. K., Jeong, J. Y., Mros, S., Harbison-Price, N., Van Zuylen, E. M., Knottenbelt, M. K., Heikal, A., Ferguson, S. A., McConnell, M. A., Cook, G. M., Krittaphol, W., Walker, G. F., … Rennison, D. (2020). Substituted sulfonamide bioisosteres of 8-hydroxyquinoline as zinc-dependent antibacterial compounds. Bioorganic & Medicinal Chemistry Letters, 30, 127110. doi: 10.1016/j.bmcl.2020.127110
Journal - Research Article
Nguyen, H. V., Campbell, K., Painter, G. F., Young, S. L., & Walker, G. F. (2020). Nanoparticle system based on amino-dextran as a drug delivery vehicle: Immune-stimulatory CpG-oligonucleotide loading and delivery. Pharmaceutics, 12, 1150. doi: 10.3390/pharmaceutics12121150
Journal - Research Article
Poller, B., Painter, G. F., & Walker, G. F. (2019). Influence of albumin in the microfluidic synthesis of PEG-PLGA nanoparticles. Pharmaceutical Nanotechnology, 7, 460-468. doi: 10.2174/2211738507666191023091938
Journal - Research Article
Zawari, M., Poller, B., Walker, G., Pearson, A., & Carr, A. C. (2019). Formulation of broccoli sprout powder in gastro-resistant capsules protects against the acidic pH of the stomach in vitro but does not increase isothiocyanate bioavailability in vivo. Antioxidants, 8(9), 359. doi: 10.3390/antiox8090359
Journal - Research Article
Kramer, K., Shields, N. J., Poppe, V., Young, S. L., & Walker, G. F. (2017). Intracellular cleavable CpG oligodeoxynucleotide-antigen conjugate enhances anti-tumor immunity. Molecular Therapy, 25(1), 62-70. doi: 10.1016/j.ymthe.2016.10.001
Journal - Research Article
Kramer, K., Young, S. L., & Walker, G. F. (2017). Comparative study of 5′- and 3′-linked CpG–antigen conjugates for the induction of cellular immune responses. ACS Omega, 2(1), 227-235. doi: 10.1021/acsomega.6b00368
Journal - Research Article
Poller, B., Strachan, C., Broadbent, R., & Walker, G. F. (2017). A minitablet formulation made from electrospun nanofibers. European Journal of Pharmaceutics & Biopharmaceutics, 114, 213-220. doi: 10.1016/j.ejpb.2017.01.022
Journal - Research Article
Smith, G. P. S., McLaughlin, A., Clarkson, A. N., Gordon, K. C., & Walker, G. F. (2017). Raman microscopic imaging of electrospun fibers made from a polycaprolactone and polyethylene oxide blend. Vibrational Spectroscopy, 92, 27-34. doi: 10.1016/j.vibspec.2017.05.002
Journal - Research Article
Walker, G., Römann, P., Poller, B., Löbmann, K., Grohganz, H., Rooney, J. S., Huff, G. S., Smith, G. P. S., Rades, T., Gordon, K. C., Strachan, C. J., & Fraser-Miller, S. J. (2017). Probing pharmaceutical mixtures during milling: The potency of low frequency Raman spectroscopy in identifying disorder. Molecular Pharmaceutics, 14(12), 4675-4684. doi: 10.1021/acs.molpharmaceut.7b00803
Journal - Research Article
Yarragudi, S. B., Richter, R., Lee, H., Walker, G. F., Clarkson, A. N., Kumar, H., & Rizwan, S. B. (2017). Formulation of olfactory-targeted microparticles with tamarind seed polysaccharide to improve nose-to-brain transport of drugs. Carbohydrate Polymers, 163, 216-226. doi: 10.1016/j.carbpol.2017.01.044
Journal - Research Article
DeRouchey, J., Schmidt, C., Walker, G. F., Koch, C., Plank, C., Wagner, E., & Rädler, J. O. (2008). Monomolecular assembly of siRNA and Poly(ethylene glycol)—peptide copolymers. Biomacromolecules, 9(2), 724-732. doi: 10.1021/bm7011482
Journal - Research Article
Fella, C., Walker, G. F., Ogris, M., & Wagner, E. (2008). Amine-reactive pyridylhydrazone-based PEG reagents for pH-reversible PEI polyplex shielding. European Journal of Pharmaceutical Sciences, 34(4-5), 309-320. doi: 10.1016/j.ejps.2008.05.004
Journal - Research Article
Knorr, V., Allmendinger, L., Walker, G. F., Paintner, F. F., & Wagner, E. (2007). An acetal-based PEGylation reagent for pH-sensitive shielding of DNA polyplexes. Bioconjugate Chemistry, 18, 1218-1225. doi: 10.1021/bc060327a
Journal - Research Article
Ledger, R., Tucker, I. G., & Walker, G. F. (2002). Quantitative capillary electrophoresis assay for the proteolytic stability of luteinizing hormone-releasing hormones. Journal of Chromatography B, 769, 235-242.
Journal - Research Article
Ledger, R., Tucker, I. G., & Walker, G. F. (2002). The metabolic barrier of the lower intestinal tract of salmon to the oral delivery of protein and peptide drugs. Journal of Controlled Release, 85, 91-103.
Journal - Research Article
Walker, G. F., Ledger, R., & Tucker, I. G. (2001). Activity of pancreatic endopeptidases towards luteinizing hormone-releasing hormones. International Journal of Pharmaceutics, 216, 77-82.
Journal - Research Article
Walker, G., Ledger, R., & Tucker, I. G. (1999). Garbomer inhibits tryptic proteolysis of luteinizing hormone-releasing hormone and N-alpha-benzoyl-L-arginine ethyl ester by binding the enzyme. Pharmaceutical Research, 16(7), 1074-1080.
Journal - Research Article
Liu, W., Price, S., Bennett, G., Maxwell, T. M. R., Zhao, C., Walker, G., & Bunt, C. (2022). A landscape review of controlled release urea products: Patent objective, formulation and technology. Journal of Controlled Release, 348, 612-630. doi: 10.1016/j.jconrel.2022.06.009
Journal - Research Other
Nguyen, H. V., Campbell, K., Painter, G. F., Young, S. L., & Walker, G. F. (2021). Data on the uptake of CpG-loaded amino-dextran nanoparticles by antigen-presenting cells [Data article]. Data in Brief, 35, 106883. doi: 10.1016/j.dib.2021.106883
Journal - Research Other
Kramer, K., Young, S. L., & Walker, G. F. (2019). Data on the uptake of reducible antigen-adjuvant conjugates by dendritic cells [Data article]. Data in Brief, 23, 103759. doi: 10.1016/j.dib.2019.103759
Journal - Research Other
Donaldson, B., Lateef, Z., Walker, G. F., Young, S. L., & Ward, V. K. (2018). Virus-like particle vaccines: Immunology and formulation for clinical translation. Expert Review of Vaccines, 17(9), 833-849. doi: 10.1080/14760584.2018.1516552
Journal - Research Other