ABSTRACT
BACKGROUND: Buparvaquone (BPQ), a hydroxynaphthoquinone derivative, has been investigated for the treatment of many infections and is recommended as the gold standard for the treatment of theileriosis. Theileriosis, an intramacrophage infection is localized mainly in reticuloendotheileial system (RES) organs. The present study investigates development of solid lipid nanoparticles (SLN) of BPQ for targeted delivery to the RES. MATERIALS AND METHODS: BPQ SLN was prepared using melt method by adding a molten mixture into aqueous Lutrol F68 solution (80°C). Larger batches were prepared up to 6 g of BPQ with GMS: BPQ, 2:1. SLN of designed size were obtained using ultraturrax and high pressure homogenizer. A freeze and thaw study was used to optimize type and concentration of cryoprotectant with Sf: Mean particle size, Si: Initial particle size <1.3. Differential scanning calorimetry (DSC), powder X-ray diffraction (XRD) and scanning electron microscope (SEM) study was performed on optimized formulation. Formulation was investigated for in vitro serum stability, hemolysis and cell uptake study. Pharmacokinetic and biodistribution study was performed in Holtzman rat. RESULTS: Based on solubility in lipid; glyceryl monostearate (GMS) was selected for preparation of BPQ SLN. Batches of BPQ SLN were optimized for average particle size and entrapment efficiency at <100 mg solid content. A combination of Solutol HS-15 and Lutrol F68 at 2% w/v and greater enabled the desired Sf/Si < 1.3. Differential scanning calorimetry and powder X-ray diffraction revealed decrease in crystallinity of BPQ in BPQ SLN while, scanning electron microscope revealed spherical morphology. BPQ SLN revealed good stability at 4°C and 25°C. Low hemolytic potential (<8%) and in vitro serum stability up to 5 h was observed. Cytotoxicity of SLN to the U937 cell was low. The macrophage cell line revealed high (52%) uptake of BPQ SLN in 1 h suggesting the potential to RES uptake. SLN revealed longer circulation and biodistrbution study confirmed high RES uptake (75%) in RES organs like liver lung spleen etc. CONCLUSION: The high RES uptake suggests BPQ SLN as a promising approach for targeted and improved delivery in theileriosis.
ABSTRACT
Nanoparticles, being small (<1,000 nm) in size, provide high surface area-to-volume ratio as compared with the bulk materials which increase the concern about their potential toxicities. The present investigation was undertaken to evaluate the genotoxic potential of asymmetric lipid polymer hybrid nanoparticles of doxycycline hydrochloride (DH lipomer) following intravenous route. DH lipomer was prepared by modified nano-precipitation method as reported earlier. Doxycyline loading was found to be 20 ± 2.5 %. Average particle size of DH lipomer and blank lipomer was 512 ± 8 and 520 ± 6 nm, respectively. Micronucleus (MN) assay was performed in adult healthy Swiss mice whereas chromosomal aberration (CA) test and comet assay were performed in healthy Holtzman rats following intravenous administration. Animals were divided into two sets, male and female, each set comprising of six groups (n = 5/group), viz., three test groups, blank lipomer (BL), vehicle control (VC), and positive control. Groups treated with 1.5 mg/kg BW DH lipomer did not show micronuclei formation in bone marrow cell, DNA damage, and CA, respectively, as compared with VC, suggesting no genotoxicity. On the other hand 3 and 6 mg/kg BW revealed significant (P > 0.001) increase in micronuclei formation, DNA damage, and chromosomal aberrations. Furthermore, BL (6 mg/kg BW) did not reveal genotoxic response in any of the tests, suggesting lipomer components as non-genotoxic. No sex-dependent variation in genotoxicity was observed. This study therefore suggests the potential safety of the proposed dose of DH lipomer at 1 mg/kg BW. An interesting highlight of the study is safety of lipomer matrix which could be exploited for other biomedical application.
