1. Department of Chemistry University of Fort Hare, Alice Eastern Cape, 5700, South Africa
2. Department of Pharmacy & Pharmacology, Wits Advanced Drug Delivery Platform Research Unit, School of Therapeutic Science, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
3. Department of Applied Chemistry, University of Johannesburg, Doornfontein Campus, Johannesburg, 2028, South Africa