NANOSCALE STUDIES ON CANCER THERAPY BY TARGETED DRUG DELIVERY SYSTEM

Abstract

Breast cancer is a heterogenous disease and differs greatly among different patients and even within each individual. This change in heterogeneity significantly changes the efficacy of cancer therapy and therefore, requires the designing of a novel formulation that can deliver therapeutics more efficiently to the cancer cells and can be directed even after the administration of the formulation. Over the last couple of decades, cancer diagnosis and treatment has improved drastically through the expansion of development in novel technologies used in diagnostic, surgical, and therapeutic treatments. However, due to the complexity and diversity of cancers, it is still a challenge to cure cancer using conventional therapies. The development of treatment strategy in cancer is one of the most difficult part because of cancer heterogeneity and challenges in selectively targeting cancer cells without affecting any healthy tissue. The conventional chemotherapy suffers from the limitations of imparting higher degree of toxicity to the body and losing its efficacy because of drug resistance. To circumvent these problems development of nanofromulation and nanomedicine has become one of the important area of research for strategizing cancer therapy. In present study, different nanoformulations of 5-Fluorouracil were prepared with the aim of improving therapeutic potential of the drug for breast cancer. The thesis comprises of five chapters (1-5), dealing with the synthesis of nanoformulations of 5-Fluorouracil which targets the drug to the desired site by use of a magnetic nanocarrier system. Chapter 1 (Introduction and Literature Review), this chapter reveals both the conventional as well as the novel technologies now being used for the treatment of cancer. It highlights the development of different treatment strategies and their mechanism of action in cancer treatment. The chapter also highlights the profile of 5-Fluorouracil (5FU) and various excipients used in the study. Beside this it includes the different commercially available nanoparticulate products for cancer treatment and their mechanism of action has also been summarized Chapter 2 deals with synthesis and characterization of magnetic nanoparticles, the work presented elaborates the synthesis and characterization of magnetic nanoparticles which are the carrier species used for targeting the drug on to the tumor cells. Superparamagnetic nanoparticles were synthesized with the help of a co-precipitation method using a 2:1 molar ratio of ferric nitrite and ferrous sulphate with liquid ammonia. The prepared nanoparticle was in the size range of 15-25 iv nm when analyzed using field emission scanning electron microscopy (FESEM) and possess superparamagnetic behavior which was reflected in the vibrating sample magnetometer (VSM) analysis. Chapter 3 focuses on the synthesis and characterization of HTCC-5FU-Magnetic nanoparticles, this chapter elaborates the formulation of HTCC-5FU magnetic nanoparticles using the bottom up approach. In this approach nanoparticles were prepared using encapsulation of 5FU along with magnetic nanoparticles to form N-(2-hydroxy) propyl-3-trimethyl ammonium chitosan chloride nanoparticles (HTCC-5FU magnetic nanoparticles). The optimization study was conducted on the developed HTCC-5FU magnetic nanoparticles for the selection of a suitable polymer concentration used for encapsulation of 5FU which provides the best encapsulation efficiency and stability to the system. The detailed physiochemical characterization of optimized formulations was also conducted using different biophysical techniques. Differential scanning calorimetry revealed that there were no physical and chemical incompatibilities between the drug and excipients. The size of nanoformulation was measured using transmission electron microscopy (TEM) and FESEM and found to be 180 nm. Infrared spectroscopy of the formulation was also performed to investigate the ionic gelation taking place between HTCC and sodium tripolyphosphate (STP) during the formulation of nanoparticles. The magnetic behaviour of the formulation was accessed using VSM analysis. Further the in vitro release kinetics of drug from the formulations were also conducted which indicated a diffusion release form the formulation showing the best fit in Korsmeyer-Peppa’s (R2 = 0.9798, n = 0.239). Chapter 4 describes the synthesis and characterization of 5FU gold magnetic nanoparticles, This chapter defines the approach used for formulation of 5FU gold magnetic nanoparticles. The formulation of a 5FU gold magnetic nanoparticles was achieved in two steps (i) the direct coating of gold on the synthesised magnetic nanoparticles to form a gold nanoparticles encapsulating magnetic particles and (ii) Conjugating 5FU with the gold magnetic nanoparticles. The formulation was characterized using the UV-spectrophotometric study revealing a consistent peak at 550 nm indicating a stable gold nanoparticles being formed. Further the characterization by TEM and zeta potential were carried out to ensure the size and stability of nanoformulations. IR spectrophotometric study of the formulations was also conducted to evaluate the mechanism of formation of 5FU on v gold nanoparticles. It was noticed that there was a decrease in the magnetic property of gold 5FU magnetic nanoparticles as compared the bare magnetic nanoparticles. Chapter 5 deals with the cytotoxicity and in vivo anticancer activity, The chapter investigates the cytotoxicity of HTCC-5FU magnetic nanoparticles and gold 5FU magnetic nanoparticles on MCF-7 cell lines using MTT assay and in vivo anticancer activity for measuring the targeting efficacy of magnetic nanoformulation (HTCC-5FU-Magnetic nanoparticles and 5FU gold magnetic nanoparticles ) in treating breast cancer. Allograft model was used to evaluate the anticancer activity of developed magnetic nanoparticles. Healthy Female Balb/c mice of 5-6 weeks of age were used for study. Tumors were generated by an orthotopic injection of 4T1 breast cancer cell lines and tumor generated mice were treated with the different formulations. Further, a constant monitoring of animal body weight and tumor volume during the course of treatment reflected a significant effect of formulations in controlling the tumor volume. Histopathological examination was performed to confirm the accumulation of magnetic nanoparticle in tumors and the therapeutic efficacy of magnetic nanoparticles was also evaluated.