BPharm, PhD (Rhodes)
Professor Walker runs an active research group that focuses on formulation and process development and design. Projects are undertaken within the current regulatory context and include development and validation of analytical tools for quality control and assurance. All projects make use of the principles of Quality by Design and entail risk assessment, design of experiments and application of Response Surface Methodology and mathematical modelling. Specifically, his current research focuses on the development, manufacture and assessment of solid oral extended release dosage forms, combination formulations, paediatric formulations, topical and transdermal drug delivery, regulatory sciences and policy development.
Recent research projects
C.I. Nkanga, R.B.Walker and R.W. Krause
pH-dependent release of isoniazid from isonicotinic acid (4-hydroxy-benzylidene)-hydrazide loaded liposomes. Journal of Drug Delivery Science and Technology, 45, 264-271 (2018).
S. Yaripour, A. Mohammadi, I. Esfanjani, R.B. Walker and S. NojavanQuantitation of zolpidem in biological fluids by electro-driven microextraction combine with HPLC-UV analysis. EXCLI Journal, 17, 349-361 (2018).
P.A. Makoni, S.M.M. Khamanga, K. Wa Kasongo and R.B. Walker
Development of a stability-indicating HPLC-ECD method for the analysis of efavirenz in formulationsusing experimental design, Pharmazie, 73(10),570-578 (2018)
H.M.K. Veerubhotla and R.B.Walker
Development and validation of a stability-indicating RP-HPLC method using quality by design for estimating captopril. Indian Journal of Pharmaceutical Sciences, 81(1), 45-56 (2019)
B.A. Witika and R.B. Walker.
Development, manufacture and characterization of niosomes for the delivery of nevirapine. Pharmazie 74(2), 91-96 (2019).
A. Manda, R.B. Walker and S.M.M. KhamangaAn artificial neural network approach to predict the effects of formulation and process variables on prednisone release from a multi-particulate system. Pharmaceutics 11(3), 109-127 (2019).
C.I. Nkanga, X. Siwe Noundou, R.B. Walker and R.W. Krause
Co-encapsulation of rifampicin and isoniazid in crude soybean lecithin liposomes. South African Journal of Chemistry 72(1), 80-87 (2019).
P.A. Makoni, K. Wa Kasongo and R.B. WalkerShort term stability testing of efavirenz-loaded solid lipid nanoparticles (SLN) and nanostructured lipid carrier (NLC) dispersions. Pharmaceutics 11(8), 397, 1-21 (2019). https://doi.org/10.3390/pharmaceutics11080397
P.A. Makoni, M.T.R. Chikukwa, S.M.M. Khamanga and R.B. Walker.
Stability Indicating HPLC-ECD method for the analysis of clarithromycin in pharmaceutical dosage forms: Method scaling versus re-validation. Scientia Pharmaceutica, 87(4), 31-51 (2019).
P.V. Ntemi, R.B. Walker and S.M.M. Khamanga
Design, evaluation and optimization of taste masked clarithromycin powder. Pharmazie, 74(12), 721-727 (2019).
C.I. Nkanga, M. Roth, R.B. Walker, X. Siwe Noundou and R.W. KrauseCo-loading of isoniazid-grafted phthalocyanine-in-cyclodextrin and rifampicin in crude soybean lecithin liposomes: Formulation, spectroscopic and biological characterization. Journal of Biomedical Nanotechnology 16, 14-28 (2020).
P.A. Makoni, J. Ranchhod, K. Wa Kasongo and R.B. WalkerThe use of quantitative analysis and Hansen solubility parameter predictions for the selection of excipients for lipid nanocarriers to be loaded with water soluble and insoluble compounds. Saudi Pharmaceutical Journal 28(3), 308-315 (2020). doi: https://doi.org/10.1016/j.jsps.2020.01.010
M. Chikukwa, M. Wesolv, A. Korzeniowska, P. Ciosek-Skibinska, R.B. Walker and S.M.M. Khamanga. Assessment of taste masking of captopril by ion-exchange resins using an electronic gustatory system. Pharmaceutical Development and Technology, 25(3), 281-289 (2020). https://doi.org/10.1080/10837450.2019.1687520
B.A. Witika, V.J. Smith and R.B. Walker
A comparative study of the effect of different stabilizers on the Critical Quality Attributes of self-assembling nano co-crystals. Pharmaceutics 12(2), 182, 1-15 (2020). https://doi.org/10.3390/pharmaceutics12020182
H.M.K. Veerubhotla and R.B. WalkerApplication of a Plackett–Burman design for screening process variables likely to impact extrusion and spheronization of a formulation. Indian Journal of Pharmaceutical Sciences 82(1), 76-87 (2020).
N.I. Okafor, C.I. Nkanga, R.B. Walker, X. Siwe Noundou and R.W. KrauseEncapsulation and physicochemical evaluation of efavirenz in liposomes. Journal of Pharmaceutical Investigation 50 (2), 201-208 (2020) https://doi.org/10.1007/s40005-019-00458-8
C Mwila and R.B. Walker
Improved stability of rifampicin in acidic media in the presence of gastric-resistant isoniazid microspheres. Pharmaceutics 12(3), 234-262 (2020) https://doi.org/10.3390/pharmaceutics12030234
B.A. Witika, V.J. Smith and R.B. WalkerQuality by design optimization of cold sonochemical synthesis of zidovudine-lamivudine nanosuspensions. Pharmaceutics 12 (4), 367 1-17 (2020). https://doi.org/10.3390/pharmaceutics12040367
M.T.R. Chikukwa, R.B. Walker and S.M.M. KhamangaFormulation and characterization of a combination captopril and hydrochlorothiazide microparticulate dosage form, Pharmaceutics 12(8), 712, 1-19 (2020). https://doi.org/10.3390/pharmaceutics12080712
A.F.B. Fauzee and RB Walker.
The impact of formulation variables on the optimization of pilot scale cream formulations. Cogent Engineering, 7(1), 1-21 (2020). https://doi.org/10.1080/23311916.2020.1804713
P.A. Makoni, K. Wa Kasongo and R.B. WalkerPreformulation studies of efavirenz with lipid excipients using thermal and spectroscopic techniques. Pharmazie, 75(9), 417-423 (2020). https://doi.org/10.1691/ph.2020.0053
B.A. Witika, P.A. Makoni, S.K. Matafwali, A.C. Kalungia, C. Mwila, A. Bapolisi, C.I. Nkanga, and R.B. Walker. Biocompatibility of biomaterials used in nanoencapsulation: Current approaches. Nanomaterials, 10 (9), 1649, 1-40 (2020). https://doi.org/10.3390/nano10091649
S. Melamane, R.B. Walker and S.M.M. KhamangaFormulation optimization of smart thermosetting lamotrigine loaded hydrogels using response surface methodology, Box-Behnken design and artificial neural networks. Drug Development and Industrial Pharmacy, 46 (9), 1402-1415 (2020). https://doi.org/10.1080/03639045.2020.1791163
Awards and grants
South Africa – India NRF Research Grant 2016 - 2018
Academy of Pharmaceutical Sciences of South Africa Distinguished Teacher of the Year Award in 2000
Academic Pharmacist of the Year National Pioneer Pharmacy Award 2019
Recent former students
Doctor of Philosophy
Ayeshah Fateemah Bebee Fauzee - Establishing a formulation design space for a generic clobetasol 17-propionate cream using the principles of Quality by Design (2014).
Ashmita Raminah - Development and assessment of ketoconazole intravaginal thermosetting hydrogel formulations (2017).
Chiluba Mwila - The development, manufacture and evaluation of sustained release gastric-resistant isoniazid and gastro-retentive microporous microspheres (2018).
Melissa Tafadzwa Ruramai Chikukwa - Formulation and characterization of a combination captopril and hydrochlorothiazide microparticulate dosage form for paediatric use (2020).
Bwalya Angel Witika - Formulation development, manufacture and evaluation of a lamivudine-zidovudine nano co-crystal thermo-responsive suspension (2020). Pascal Vitalis Ntemi
Pascal Vitalis Ntemi - Formulation, development and assessment of Devil’s Claw loaded phyto-elastosomes in thermo-responsive hydrogels (2020).
Master of Science (Pharmacy) in Pharmaceutics
Chiedza Cathrine Zindove - Development and assessment of sustained release stavudine loaded microparticles (2014).
Tendai Jonathon Chanakira - Development, manufacture and assessment of mometasone furoate loaded nanostructured lipid carriers (2014).
Pedzisai A Makoni - Formulation, development and assessment of efavirenz-loaded lipid nanocarriers (2014). Co-supervisor. Supervisor. Dr K Wa Kasongo
Samantha Yolanda Mukozhiwa Development and assessment of gastroretentive sustained release captopril tablets (2014). Co-supervisor. Supervisor Dr SMM Khamanga
Tawanda Gay Dube - Formulation, development and assessment of tenofovir disoproxil fumarate-loaded pellets (2015).
Henusha Devi Jhundoo - An investigation into the feasibility of incorporating ketoconazole into solid lipid microparticles (2015).
Farai Arthur Mhaka - Development and manufacture of sustained release captopril pellets (2015).
Sonja Koekemoer - Gradient high performance liquid chromatographic method for the simultaneous analysis of efavirenz, emtricitabine and tenofovir (2016).
Hari Mani Krishna Veerubhotla - Development of captopril pellets using the principles of Quality by Design (2016).
Janeeta Ranchhod - Formulation, development and evaluation of lipid nanocarriers for minocycline hydrochloride (2017).
Anjana Makan - Development and assessment of gastric-retentive sustained release metronidazole microcapsules (2017).
Bwalya Angel Witika - The development, manufacture and characterization of niosomes intended to deliver nevirapine to the brain (2017).
Shakemore Tinashe Kangausaru - Formulation development, manufacture and evaluation of hydralazine hydrochloride microspheres (2017). Supervisor. Co-supervisor Dr S.M.M. Khamanga
Pascal Vitalis Ntemi - Taste masking of clarithromycin with ion-exchange resins (2017).
Melissa Tafadzwa Ruramai Chikukwa - Preparation and evaluation of captopril-ion exchange resin complexes (2017)
Tanyaradzwa Gracious Musakana - The development, manufacture and evaluation of a self-micro-emulsifying drug delivery system for efavirenz (2018).
Omoyosola Omolola Oridota - Development and assessment of gastroretentive sustained release captopril micro-balloons (March 2018).
Tsitsi Mudyahoto - Formulation, characterization and optimization of self-nanoemulsifying drug delivery systems (SNEDDS) loaded with artemether and lumefantrine (2018).
Grace Shalom Govere - Development and assessment of solid gliclazide-HPMC-AS dispersion delivery
Siyabonga Melamane - Development and assessment of a smart thermosetting intranasal hydrogel for lamotrigine (2018).
Hariska Naidu - Development, formulation and assessment of an orodispersible taste-masked sildenafil film for paediatric use (2019).
Arthur Manda - Application of Quality by Design to the manufacture of a multiparticulate prednisone dosage form (2019).
Fadzai Naomi Mungoshi - The development, manufacture and characterization of tenofovir encapsulated liposomes (2019).
Kudzai Gabriella Makoni - Preparation, characterization and optimization of carbamazepine based pellets prepared by extrusion-spheronization technique (2019).
Tavonga Tyomai Mandava - Development and assessment of a fixed dose combination of perindopril arginine and indapamide loaded microparticles (2020).
Registered with South African Pharmacy Council
Member of the Pharmaceutical Society of South Africa
Hobbies and interests
All sports, photography and reading