Browsing by Author "Hayeshi, Rose"

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Curdlan-Conjugated PLGA Nanoparticles Possess Macrophage Stimulant Activity and Drug Delivery Capabilities
(Springer, 2015-03-28) Tukulula, Matshawandile; Hayeshi, Rose; Fonteh, Pascaline; Meyer, Debra; Ndamase, Abongile; Madziva, Michael T.; Khumalo, Vincent; Lubuschagne, Philip; Naicker, Brendon; Swai, Hulda; Dube, Admire
Purpose There is significant interest in the application of nanoparticles to deliver immunostimulatory signals to cells.We hypothesized that curdlan (immune stimulating polymer) could be conjugated to PLGA and nanoparticles from this copolymer would possess immunostimulatory activity, be non-cytotoxic and function as an effective sustained drug release system. Methods Carbodiimide chemistry was employed to conjugate curdlan to PLGA. The conjugate (C-PLGA) was characterized using 1H and 13C NMR, FTIR, DSC and TGA. Nanoparticles were synthesized using an emulsion-solvent evaporation technique. Immunostimulatory activity was characterized in THP-1 derived macrophages. MTTassay and real-time impedance measurements were used to characterize polymer and nanoparticle toxicity and uptake in macrophages. Drug delivery capability was assessed across Caco-2 cells using rifampicin as a model drug. Results Spectral characterization confirmed successful synthesis of C-PLGA. C-PLGA nanoparticles enhanced phosphorylated ERK production in macrophages indicating cell stimulation. Nanoparticles provided slow release of rifampicin across Caco-2 cells. Polymers but not nanoparticles altered the adhesion profiles of the macrophages. Impedance measurements suggested Ca2+ dependent uptake of nanoparticles by the macrophages. Conclusions PLGA nanoparticles with macrophage stimulating and sustained drug delivery capabilities have been prepared. These nanoparticles can be used to stimulate macrophages and concurrently deliver drug in infectious disease therapy.
Effects of protein binding on the biodistribution of PEGylated PLGA nanoparticles post oral administration
(Elsevier B.V., 2012-03-15) Semete, Boitumelo; Booysen, Laetitia; Kalombo, Lonji; Ramalapa, Bathabile; Hayeshi, Rose; Swai, Hulda
The surface of nanoparticles is often functionalised with polymeric surfactants, in order to increase systemic circulation time. This has been investigated mainly for intravenously administered nanoparticles. This study aims to elucidate the effect of surface coating with various concentrations of polymeric surfactants (PEG and Pluronics F127) on the in vitro protein binding as well as the tissue biodistribution, post oral administration, of PLGA nanoparticles. The in vitro protein binding varied depending on the polymeric surfactant used. However, in vivo, 1% PEG and 1% Pluronics F127 coated particles presented similar biodistribution profiles in various tissues over seven days. Furthermore, the percentage of PEG and Pluronics coated particles detected in plasma was higher than that of uncoated PLGA particles, indicating that systemic circulation time can also be increased with oral formulations. The difference in the in vitro protein binding as a result of the different poloxamers used versus similar in vivo profiles of these particles indicates that in vitro observations for nanoparticles cannot represent or be correlated to the in vivo behaviour of the nanoparticles. Our results therefore suggest that more studies have to be conducted for oral formulations to give a better understanding of the kinetics of the particles.
Nanomedicine: Past, present and future - A global perspective.
(Elsevier Inc, 2015-12-18) Chang, Esther; Harford, Joe; Eaton, Michael; Boisseau, Patrick; Dube, Admire; Hayeshi, Rose; Swai, Hulda; Lee, Dong
Nanomedicine is an emerging and rapidly evolving field and includes the use of nanoparticles for diagnosis and therapy of a variety of diseases, as well as in regenerative medicine. In this mini-review, leaders in the field from around the globe provide a personal perspective on the development of nanomedicine. The focus lies on the translation from research to development and the innovation supply chain, as well as the current status of nanomedicine in industry. The role of academic professional societies and the importance of government funding are discussed. Nanomedicine to combat infectious diseases of poverty is highlighted along with other pertinent examples of recent breakthroughs in nanomedicine. Taken together, this review provides a unique and global perspective on the emerging field of nanomedicine.
Oral lipid-based nanoformulation of tafenoquine enhanced bioavailability and blood stage antimalarial efficacy and led to a reduction in human red blood cell loss in mice
(Dovepress, 2015-02-20) Melariri, Paula; Kalombo, Lonji; Nkuna, Patric; Dube, Admire; Hayeshi, Rose; Ogutu, Benhards; Gibhard, Liezl; deKock, Carmen; Smith, Peter; Wiesner, Lubbe; Swai, Hulda
: Tafenoquine (TQ), a new synthetic analog of primaquine, has relatively poor bioavailability and associated toxicity in glucose-6-phosphate dehydrogenase (G6PD)-deficient individuals. A microemulsion formulation of TQ (MTQ) with sizes 20 nm improved the solubility of TQ and enhanced the oral bioavailability from 55% to 99% in healthy mice (area under the curve 0 to infinity: 11,368±1,232 and 23,842±872 min⋅µmol/L) for reference TQ and MTQ, respectively. Average parasitemia in Plasmodium berghei-infected mice was four- to tenfold lower in the MTQ-treated group. In vitro antiplasmodial activities against chloroquinesensitive and chloroquine-resistant strains of Plasmodium falciparum indicated no change in half maximal inhibitory concentration, suggesting that the microemulsion did not affect the inherent activity of TQ. In a humanized mouse model of G6PD deficiency, we observed reduction in toxicity of TQ as delivered by MTQ at low but efficacious concentrations of TQ. We hereby report an enhancement in the solubility, bioavailibility, and efficacy of TQ against blood stages of Plasmodium parasites without a corresponding increase in toxicity.
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.
State of the art and future directions in nanomedicine for tuberculosis.
(Expert Opinion on Drug Delivery, 2013-12-01) Dube, Admire; Lemmer, Yolandy; Hayeshi, Rose; Balogun, Mohammed; Labuschagne, Philip; Swai, Hulda; Kalombo, Lonji
Introduction: Tuberculosis (TB) ranks the second leading cause of death from an infectious disease worldwide. However, treatment of TB is affected by poor patient compliance due to the requirement for daily drug administration, for lengthy periods of time, often with severe drug-induced side effects. Nanomedicines have the potential to improve treatment outcomes by providing therapies with reduced drug doses, administered less frequently, under shortened treatment durations. Areas covered: In this article, we present the pathophysiology of the disease, focusing on pulmonary TB and the characteristics of drugs used in treatment and discuss the application of nanomedicines within this scope. We also discuss new formulation approaches for TB nanomedicines and directions for future research. Expert opinion: Nanomedicines have the potential to improve TB treatment outcomes. New approaches such as nanoparticle systems able to impact the immune response of macrophages and deliver drug intracellularly, as well as the use of polymer–drug conjugates for drug delivery, are likely to play an important role in TB nanomedicines in future. However, further research is required before TB nanomedicines can be translated to the clinic.