Spherical and rod-shaped gold nanoparticles with surface poly (ethylene glycol) (PEG) chains were characterized for size, shape, charge, poly dispersity and surface plasmon resonance. The nanoparticles were injected intravenously to 6-8 weeks old female nu/nu mice bearing orthotopic ovarian tumors and their biodistribution in vital organs was compared. Gold nanorods were taken up to a lesser extent by the liver, had longer circulation time in the blood, and higher accumulation in the tumors, compared with their spherical counterparts. The cellular uptake of PEGylated gold nanoparticles by a murine macrophage-like cell line as a function of geometry was examined. Compared to nanospheres, PEGylated gold nanorods were taken up to a lesser extent by macrophages. These studies point to the importance of gold nanoparticle geometry and surface properties on transport across biological barriers.

The purpose of this study was to model data from a head to head comparison of the in vivo fate of hyper-branched PAMAM dendrimers with linear HPMA copolymers in order to understand the influence of molecular weight (MW), hydrodynamic size (Rh) and polymer architecture on biodistribution in tumor-bearing mice using compartmental pharmacokinetic analysis. Plasma concentration data was modeled by two-compartment analysis using Winnonlin® to obtain elimination clearance (E.CL) and plasma exposure (AUCplasma). Renal clearance (CLR) was calculated from urine data collected over 1 week. A plasma-tumor link model was fitted to experimental plasma and tumor data by varying the tumor extravasation (K4, K6) and elimination (K5) rate constants using multivariable constrained optimization solver in Matlab®. Tumor exposures (AUCtumor) were computed from area under the tumor concentration time profile curve by the linear trapezoidal method. Along with MW and Rh, polymer architecture was critical in affecting the blood and tumor pharmacokinetics of the PAMAM-OH dendrimers and HPMA copolymers. Elimination clearance decreased more rapidly with increase in hydrodynamic size for PAMAM-OH dendrimers as compared to HPMA copolymers. HPMA copolymers were eliminated renally to a higher extent than PAMAM-OH dendrimers. These results are suggestive of a difference in extravasation of polymers of varying architecture through the glomerular basement membrane. While the linear HPMA copolymers can potentially reptate through a pore smaller in size than their hydrodynamic radii in a random coil conformation, PAMAM dendrimers have to deform in order to permeate across the pores. With increase in molecular weight or generation, the deforming capacity of PAMAM-OH dendrimers is known to decrease, making it harder for higher generation PAMAM-OH dendrimers to sieve through the glomerulus as compared to HPMA copolymers of comparable molecular weights. PAMAM-OH dendrimer had greater tumor extravsation rate constants and higher tumor to plasma exposure ratios than HPMA copolymers of comparable molecular weights which indicated that in the size range studied, when in circulation, PAMAM-OH dendrimers had a higher affinity to accumulate in the tumor than the HPMA copolymers.

Gynecological malignancies such as cervical, endometrial and ovarian cancer still are the leading causes of death for women worldwide. However, standard therapies such as surgical cytoreduction and systemic chemotherapy combined with radiation have shown limited-efficacy by accessibility as well as nonspecific toxicity. To overcome those limitations, we previously reported about the development of a muco-adhesive, chitosan-hybrid gel (CS(BCDDP)) embedded with alginate beads containing cisplatin (CDDP) for a local, intraperitoneal application (# 3232, AACR 2011). Here we report the results of CDDP release from the (CS(BCDDP)), its cellular activity in vitro and CDDP accumulation to genomic DNA (gDNA) of tissues in vivo. To determine the amount of CDDP released from (CS(BCDDP)) in vitro, we used a colorimetric SnCl2 assay following the incubation in 0.9% NaCl solution for 24 hrs. (CS(BCDDP)) demonstrated successful release of 90% CDDP within 2 hrs and consistent CDDP-release could be maintained for up to 24 hrs. To test activity of CDDP released from (CS(BCDDP)), clonogenic assay was performed with Hela (human cervical adenocarcinoma) cells. Cells treated with (CS(BCDDP)) demonstrated a significantly low number of colonies, generating 9 (± 6) colonies per 500 cells seeded compared with 233 (± 10) colonies per 500 cells treated with an empty, no drug containing control gel (CS). To further assess CDDP accumulation to gDNA of tissues in vivo, inductively coupled plasma mass spectrometry (ICP-MS) was performed with tissue samples obtained from the left peritoneal sidewall of female nude mice following treatment with a control gel mixed with CDDP (CSCDDP), (CS(BCDDP)), and intravenously (i.v.) CDDP(CDDPIV). The results demonstrated a greater than three-time enhancement of CDDP-accumulation to the gDNA from (CS(BCDDP)) when compared to CDDPIV. Moreover, (CS(BCDDP)) also demonstrated higher accumulation of CDDP to gDNA when compared with CSCDDP. Relative values were 3.2 (±0.9) for (CS(BCDDP)) and 1.3 (± 0.4) for CSCDDP compared to values obtained from CDDPIV. Our in vitro and in vivo results, strongly suggest the feasibility of applying this hybrid gel locally to mucosal surfaces of the female reproductive tract and its advantage for intraperitoneal drug accumulation. Currently ongoing experiments are evaluating the efficacy and safety of our hybrid gel/CDDP in orthotopic endometrial, ovarian and cervical cancer animal models. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1948. doi:1538-7445.AM2012-1948