Browsing by Author "Naidoo, Saloshnee"

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Design and formulation of nano-sized spray dried efavirenz-part I: influence of formulation parameters
(Springer Nature Switzerland AG., 2012-10-25) Katata, Lebogang; Tshweu, Lesego; Naidoo, Saloshnee; Kalombo, Lonji; Swai, Hulda
Efavirenz (EFV) is one of the first-line antiretroviral drugs recommended by the World Health Organisation for treating HIV. It is a hydrophobic drug that suffers from low aqueous solubility (4 μg/mL), which leads to a limited oral absorption and low bioavailability. In order to improve its oral bioavailability, nano-sized polymeric delivery systems are suggested. Spray dried polycaprolactone-efavirenz (PCL-EFV) nanoparticles were prepared by the double emulsion method. The Taguchi method, a statistical design with an L8 orthogonal array, was implemented to optimise the formulation parameters of PCL-EFV nanoparticles. The types of sugar (lactose or trehalose), surfactant concentration and solvent (dichloromethane and ethyl acetate) were chosen as significant parameters affecting the particle size and polydispersity index (PDI). Small nanoparticles with an average particle size of less than 254 ± 0.95 nm in the case of ethyl acetate as organic solvent were obtained as compared to more than 360 ± 19.96 nm for dichloromethane. In this study, the type of solvent and sugar were the most influencing parameters of the particle size and PDI. Taguchi method proved to be a quick, valuable tool in optimising the particle size and PDI of PCL-EFV nanoparticles. The optimised experimental values for the nanoparticle size and PDI were 217 ± 2.48 nm and 0.093 ± 0.02.
Preparation of rifampicin/poly(d,l-lactice) nanoparticles for sustained release by supercritical assisted atomization technique
(Elsevier, 2014-11) Labuschagne, Philip; Adami, Renata; Liparoti, Sara; Naidoo, Saloshnee; Reverchon, E.; Swai, Hulda
In this work supercritical assisted atomization (SAA) process was used for the co-precipitation of poly(d,l-lactide) (PDLLA) and rifampicin (RIF) as nanoparticles for sustained release applications. The effect of the variation of PDLLA/RIF ratio on co-precipitate characteristics was mainly investigated. The precipitated particles were analyzed in terms of their morphological, thermodynamic and crystallographic properties. In addition, loading efficiency and in-vitro release studies were conducted. Spherical PDLLA/RIF nanoparticles with mean diameter ranging from 123 to 148 nm were prepared. Loading efficiency was greater than 100% resulting in RIF loadings of 28.8 to 50.5%. X-ray diffraction revealed that the encapsulated RIF is in an amorphous state, while NMR spectra indicated no structural modifications after the SAA process. In-vitro release studies showed an initial burst release of 80–87% of total RIF loaded, necessary to suppress the generation of resistance by the microorganism, followed by first-order sustained release between 0.4 and 0.8 mg/L RIF per day over a period of 17 days.
Spray-Dried, Nanoencapsulated, Multi-Drug Anti-Tuberculosis Therapy Aimed at OnceWeekly Administration for the Duration of Treatment
(MDPI, 2019-08-15) Kalombo, Lonji; Lemmer, Yolandy; Semete-Makokotlela, Boitumelo; Ramalapa, Bathabile; Nkuna, Patric; Booysen, Laetitia; Naidoo, Saloshnee; Hayeshi, Rose; Verschoor, Jan; Swai, Hulda
Aiming to improve the treatment outcomes of current daily tuberculosis (TB) chemotherapy over several months, we investigated whether nanoencapsulation of existing drugs would allow decreasing the treatment frequency to weekly, thereby ultimately improving patient compliance. Nanoencapsulation of three first-line anti-TB drugs was achieved by a unique, scalable spray-drying technology forming free-flowing powders in the nanometer range with encapsulation e ciencies of 82, 75, and 62% respectively for rifampicin, pyrazinamide, and isoniazid. In a pre-clinical study on TB infected mice, we demonstrate that the encapsulated drugs, administered once weekly for nine weeks, showed comparable e cacy to daily treatment with free drugs over the same experimental period. Both treatment approaches had equivalent outcomes for resolution of inflammation associated with the infection of lungs and spleens. These results demonstrate how scalable technology could be used to manufacture nanoencapsulated drugs. The formulations may be used to reduce the oral dose frequency from daily to once weekly in order to treat uncomplicated TB.