Developing nanoparticulate delivery systems that will allow easy movement and localisation of a drug to the target tissue and provide more controlled release of the drug in vivo is a challenge for researchers in nanomedicine. The aim of this study was to evaluate the biodistribution of two nano-delivery systems namely, poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles containing samarium-153 oxide ([153Sm]Sm2O3) as radiotracer and solid lipid nanoparticles (SLNs) containing technetium-99m-methylene diphosphonate (99mTc-MDP), after oral and intravenous administration to rats to prove that orally administered nanoparticles indeed alter the biodistribution of a drug as compared to the drug on its own. Stable samarium-152 oxide ([152Sm]Sm2O3) was encapsulated in polymeric PLGA nanoparticles. These were then activated in a nuclear reactor to produce radioactive [153Sm]Sm2O3 loaded-PLGA nanoparticles. Both the stable nanoparticles as well as the fully decayed activated nanoparticles, were characterized for size, Zeta potential and morphology using dynamic light scattering and scanning electron microscopy (SEM) or transmission electron microscopy (TEM), respectively. SLNs were a form of delivery system which was used to encapsulate the radiotracer, 99mTc-MDP. 99mTc-MDP SLNs were characterized before and after encapsulation for size and Zeta potential. Both nanoparticle compounds were orally and intravenously (IV) administered to rats in order to trace their uptake and biodistribution through imaging and ex vivo biodistribution studies. The PLGA nanoparticles containing [153Sm]Sm2O3 were spherical in morphology and smaller than 500 nm, therefore meeting the objective of producing radiolabelled nanoparticles smaller than 500 nm. Various parameters were optimized to obtain an average particle size ranging between 250 and 300 nm, with an average polydispersity index (PDI) ≤ 0.3 after spray drying. The particles had a Zeta potential ranging between 5 and 20 mV. The Sm2O3-PLGA nanoparticles had an average size of 281 ± 6.3 nm and a PDI average of 0.22. The orally administered [153Sm]Sm2O3-PLGA nanoparticles were deposited in various organs which includes bone with a total of 0.3% of the Injected Dose (ID) per gram vs the control of [153Sm]Sm2O3which showed no uptake in any organs except the GI-tract. The IV injected [153Sm]Sm2O3-PLGA nanoparticles exhibit the highest localisation of nanoparticles in the spleen (8.63%ID/g) and liver (3.07%ID/g). The 99mTc-MDP-labelled SLN were spherical and smaller than 500 nm. Optimization of the MDP-loaded SLN emulsions yielded a slightly higher PDI of ≥0.5 and a size range between 150 and 450 nm. The Zeta potential was between -30 and -2 mV. The MDP-loaded SLN had an average size of 256 ± 5.27 and an average PDI of 0.245.The orally administered 99mTc-MDP SLN had the highest localisation of nanoparticles in the kidneys (8.50%ID/g) and stomach (8.04%ID/g) while the control, 99mTc-MDP had no uptake in any organs except the GI-tract. The IV injected 99mTc-MDP SLN also exhibited a high localisation of particles in the kidneys (3.87%ID/g) followed by bone (2.66%ID/g). Both the IV and oral 99mTc-MDP SLN reported significantly low deposition values in the heart, liver and spleen. Based on the imaging and the biodistribution studies, it can be concluded that there was a significant transfer of the orally administrated radiolabelled nanoparticles from the stomach to other organs vs the controls. Furthermore, this biodistribution of the nano carriers warrants surface modification and optimisation of the nanoparticles to avoid higher particle localisation in the stomach. / MSc (Pharmaceutics), North-West University, Potchefstroom Campus, 2014

Developing nanoparticulate delivery systems that will allow easy movement and localisation of a drug to the target tissue and provide more controlled release of the drug in vivo is a challenge for researchers in nanomedicine. The aim of this study was to evaluate the biodistribution of two nano-delivery systems namely, poly(D,L-lactide-co-glycolide) (PLGA) nanoparticles containing samarium-153 oxide ([153Sm]Sm2O3) as radiotracer and solid lipid nanoparticles (SLNs) containing technetium-99m-methylene diphosphonate (99mTc-MDP), after oral and intravenous administration to rats to prove that orally administered nanoparticles indeed alter the biodistribution of a drug as compared to the drug on its own. Stable samarium-152 oxide ([152Sm]Sm2O3) was encapsulated in polymeric PLGA nanoparticles. These were then activated in a nuclear reactor to produce radioactive [153Sm]Sm2O3 loaded-PLGA nanoparticles. Both the stable nanoparticles as well as the fully decayed activated nanoparticles, were characterized for size, Zeta potential and morphology using dynamic light scattering and scanning electron microscopy (SEM) or transmission electron microscopy (TEM), respectively. SLNs were a form of delivery system which was used to encapsulate the radiotracer, 99mTc-MDP. 99mTc-MDP SLNs were characterized before and after encapsulation for size and Zeta potential. Both nanoparticle compounds were orally and intravenously (IV) administered to rats in order to trace their uptake and biodistribution through imaging and ex vivo biodistribution studies. The PLGA nanoparticles containing [153Sm]Sm2O3 were spherical in morphology and smaller than 500 nm, therefore meeting the objective of producing radiolabelled nanoparticles smaller than 500 nm. Various parameters were optimized to obtain an average particle size ranging between 250 and 300 nm, with an average polydispersity index (PDI) ≤ 0.3 after spray drying. The particles had a Zeta potential ranging between 5 and 20 mV. The Sm2O3-PLGA nanoparticles had an average size of 281 ± 6.3 nm and a PDI average of 0.22. The orally administered [153Sm]Sm2O3-PLGA nanoparticles were deposited in various organs which includes bone with a total of 0.3% of the Injected Dose (ID) per gram vs the control of [153Sm]Sm2O3which showed no uptake in any organs except the GI-tract. The IV injected [153Sm]Sm2O3-PLGA nanoparticles exhibit the highest localisation of nanoparticles in the spleen (8.63%ID/g) and liver (3.07%ID/g). The 99mTc-MDP-labelled SLN were spherical and smaller than 500 nm. Optimization of the MDP-loaded SLN emulsions yielded a slightly higher PDI of ≥0.5 and a size range between 150 and 450 nm. The Zeta potential was between -30 and -2 mV. The MDP-loaded SLN had an average size of 256 ± 5.27 and an average PDI of 0.245.The orally administered 99mTc-MDP SLN had the highest localisation of nanoparticles in the kidneys (8.50%ID/g) and stomach (8.04%ID/g) while the control, 99mTc-MDP had no uptake in any organs except the GI-tract. The IV injected 99mTc-MDP SLN also exhibited a high localisation of particles in the kidneys (3.87%ID/g) followed by bone (2.66%ID/g). Both the IV and oral 99mTc-MDP SLN reported significantly low deposition values in the heart, liver and spleen. Based on the imaging and the biodistribution studies, it can be concluded that there was a significant transfer of the orally administrated radiolabelled nanoparticles from the stomach to other organs vs the controls. Furthermore, this biodistribution of the nano carriers warrants surface modification and optimisation of the nanoparticles to avoid higher particle localisation in the stomach. / MSc (Pharmaceutics), North-West University, Potchefstroom Campus, 2014

Research on nanoparticles for pharmaceutical applications has become increasingly popular in recent years. N-trimethyl chitosan chloride (TMC) is a cationic polymer that can enhance absorption across mucosal surfaces. It has been explored as a nanoparticulate drug delivery system for the delivery of vaccines, vitamins, insulin and cancer medication. It has special interest for intravenous use, as it is soluble over a wide range of pH values. However, polycationic nanoparticles run a great risk for intravenous toxicity, as the positive surface charge allows easy electrostatic interactions with negatively charged blood components, such as red blood cells and plasma proteins. Additionally, the small size of the nanoparticles permits the binding of more proteins per mass, than larger particles do. These interactions can lead to extensive hemolysis, cell aggregation, complement activation, inflammation and fast clearance of the particles from the circulation. A decrease in the surface charge density can ameliorate these toxic interactions. Such a decrease is achieved by adding poly(ethylene) glycol (PEG) to the particle’s formulation. PEG creates a steric shield around the particles, preventing a certain extent of interaction between the particles and the blood components. To be able to use TMC nanoparticles as a successful drug delivery system, the hemocompatibility must first be determined, which was the aim of this study. The influence of particle size, concentration and the addition of PEG were also examined. The extent of hemolysis and cell aggregation caused by the experimental groups (20% and 60% concentration small TMC nanoparticles, 20% larger TMC nanoparticles and 20% cross-linked PEGTMC nanoparticles) were determined by incubating the groups with whole blood and/or blood components. Complement activation was determined with a Complement C3 Human enzyme-linked immunosorbent assay (ELISA) and plasma protein interactions were quantified through rapid equilibrium dialysis and a colorimetric assay. It was determined that 60% concentration small TMC nanoparticles caused 49.08 ± 2.538% hemolysis at the end of a 12-hour incubation period, significantly more than any other experimental group. This group had also caused mild aggregation of the white blood cells and platelets. This was the greatest extent of cell aggregation seen in any of the groups. No significant complement activation was seen by any of the experimental groups. Because of the cationic nature of the particles, all groups had more than 50% of the initial particles in the sample bound to plasma proteins after a 4-hour incubation period. However, at 90.68 ± 0.828%, the 60% small TMC nanoparticles had had significantly more interaction with the plasma proteins than the other groups. Through the experimental measurements it was revealed that TMC nanoparticles had hemotoxic effects at high concentrations. The addition of PEG to the particle formulation stabilized the particles and decreased their zeta potential , but had no significant effect on improving hemocompatibility. It was concluded that although further tests are needed, TMC nanoparticles seem to have potential as a successful intravenous carrier for high molecular weight active pharmaceutical ingredients. / MSc (Pharmaceutics), North-West University, Potchefstroom Campus, 2014

Research on nanoparticles for pharmaceutical applications has become increasingly popular in recent years. N-trimethyl chitosan chloride (TMC) is a cationic polymer that can enhance absorption across mucosal surfaces. It has been explored as a nanoparticulate drug delivery system for the delivery of vaccines, vitamins, insulin and cancer medication. It has special interest for intravenous use, as it is soluble over a wide range of pH values. However, polycationic nanoparticles run a great risk for intravenous toxicity, as the positive surface charge allows easy electrostatic interactions with negatively charged blood components, such as red blood cells and plasma proteins. Additionally, the small size of the nanoparticles permits the binding of more proteins per mass, than larger particles do. These interactions can lead to extensive hemolysis, cell aggregation, complement activation, inflammation and fast clearance of the particles from the circulation. A decrease in the surface charge density can ameliorate these toxic interactions. Such a decrease is achieved by adding poly(ethylene) glycol (PEG) to the particle’s formulation. PEG creates a steric shield around the particles, preventing a certain extent of interaction between the particles and the blood components. To be able to use TMC nanoparticles as a successful drug delivery system, the hemocompatibility must first be determined, which was the aim of this study. The influence of particle size, concentration and the addition of PEG were also examined. The extent of hemolysis and cell aggregation caused by the experimental groups (20% and 60% concentration small TMC nanoparticles, 20% larger TMC nanoparticles and 20% cross-linked PEGTMC nanoparticles) were determined by incubating the groups with whole blood and/or blood components. Complement activation was determined with a Complement C3 Human enzyme-linked immunosorbent assay (ELISA) and plasma protein interactions were quantified through rapid equilibrium dialysis and a colorimetric assay. It was determined that 60% concentration small TMC nanoparticles caused 49.08 ± 2.538% hemolysis at the end of a 12-hour incubation period, significantly more than any other experimental group. This group had also caused mild aggregation of the white blood cells and platelets. This was the greatest extent of cell aggregation seen in any of the groups. No significant complement activation was seen by any of the experimental groups. Because of the cationic nature of the particles, all groups had more than 50% of the initial particles in the sample bound to plasma proteins after a 4-hour incubation period. However, at 90.68 ± 0.828%, the 60% small TMC nanoparticles had had significantly more interaction with the plasma proteins than the other groups. Through the experimental measurements it was revealed that TMC nanoparticles had hemotoxic effects at high concentrations. The addition of PEG to the particle formulation stabilized the particles and decreased their zeta potential , but had no significant effect on improving hemocompatibility. It was concluded that although further tests are needed, TMC nanoparticles seem to have potential as a successful intravenous carrier for high molecular weight active pharmaceutical ingredients. / MSc (Pharmaceutics), North-West University, Potchefstroom Campus, 2014