Biodistribution of Lipiodol following hepatic arterial injection

Preparation and Characterization of Hyaluronic Acid-Polycaprolactone Copolymer Micelles for the Drug Delivery of Radioactive Iodine-131 Labeled Lipiodol

Micelles, with the structure of amphiphilic molecules including a hydrophilic head and a hydrophobic tail, are recently developed as nanocarriers for the delivery of drugs with poor solubility. In addition, micelles have shown many advantages, such as enhanced permeation and retention (EPR) effects, prolonged circulation times, and increased endocytosis through surface modification. In this study, we measured the critical micelle concentrations, diameters, stability, and cytotoxicity and the cell uptake of micelles against hepatic cells with two kinds of hydrophilic materials: PEG-PCL and HA-g-PCL. We used ¹³¹I as a radioactive tracer to evaluate the stability, drug delivery, and cell uptake activity of the micelles. The results showed that HA-g-PCL micelles exhibited higher drug encapsulation efficiency and stability in aqueous solutions. In addition, the ¹³¹I-lipiodol loaded HA-g-PCL micelles had better affinity and higher cytotoxicity compared to HepG2 cells.

Therapeutic Strategies in HCC: Radiation Modalities

Patients with hepatocellular carcinoma (HCC) comply with an advanced disease and are not eligible for radical therapy. In this distressed scenario new treatment options hold great promise; among them transarterial chemoembolization (TACE) and transarterial metabolic radiotherapy (TAMR) have shown efficacy in terms of both tumor shrinking and survival. External radiation therapy (RTx) by using novel three-dimensional conformal radiotherapy has also been used for HCC patients with encouraging results while its role had been limited in the past for the low tolerance of surrounding healthy liver. The rationale of TAMR derives from the idea of delivering exceptional radiation dose locally to the tumor, with cell killing intent, while preserving normal liver from undue exposition and minimizing systemic irradiation. Since the therapeutic efficacy of TACE is being continuously disputed, the TAMR with ¹³¹I Lipiodol or ⁹⁰Y microspheres has gained consideration providing adequate therapeutic responses regardless of few toxicities. The implementation of novel radioisotopes and technological innovations in the field of RTx constitutes an intriguing field of research with important translational aspects. Moreover, the combination of different therapeutic approaches including chemotherapy offers captivating perspectives. We present the role of the radiation-based therapies in hepatocellular carcinoma patients who are not entitled for radical treatment.

Iodine-131-lipiodol therapy in hepatic tumours

The incidence of hepatocellular carcinoma (HCC) is worldwide sharply on the rise and patients with advanced disease carry a poor prognosis. HCC is the sixth most common cancer and the third leading cause of cancer associated deaths in the world. Intra-arterially administered (131)I-Lipiodol is selectively retained by hepatocellular carcinomas, and has been used as a vehicle for delivery of therapeutic agents to these tumours. In this review we focus on the therapeutic indications, usefulness and methods of treatment with 131-Iodine Lipiodol. The effectiveness of (131)I-Lipiodol treatment is proven both in the treatment of HCC with portal thrombosis and also as an adjuvant to surgery after the resection of HCCs. It is at least as effective as chemoembolization and is tolerated much better. Severe liver dysfunction represents theoretic contraindication for radioembolization as well as for TACE. In such cases (131)I-Lipiodol is an alternative therapy option especially in tumours smaller than 6cm.

Liver Embolizations in Oncology. A Review. Part II. Arterial Radioembolizations, Portal Venous Embolizations, Experimental Arterial Embolization Procedures

Arterial embolization of the liver may temporarily retard the growth of its primary and secondary tumors which are both mainly nourished arterially. Addition of radioisotopes, mostly (131)I or (90)Y, results in radioembolizations which predominantly act by radiation and less by ischemia. They may therefore be utilized in the absence of portal venous flow when conventional embolization is hazardous. (131)I-oily radioembolization seems to prolong short-term survival in such patients with unresectable hepatocellular cancers, and to improve the prognosis after resection of hepatocellular cancer. The procedure does however not palliate better than "cold" chemoembolization in patients with preserved portal flow, except for having milder side effects. Embolization with (90)Y-coupled microspheres may shrink primary and secondary liver tumors but has so far unproven effects on survival. Embolization of portal venous branches gives compensatory hypertrophy of the non-embolized liver and can increase the volume of the future remnant liver before resection. This diminishes the risk for postoperative liver failure after extensive resection and/or in the presence of chronic liver disease, and permits wider surgical indications. Tumor growth may however be accelerated, and the hypertrophy is inhibited by severe liver parenchymal disease in which situation the method would be most needed. Experimental use of liver arterial embolizations includes combined arterial and portal embolizations, i.e. "chemical hepatectomy," arterial embolizations before external radiotherapy, administration of boron for neutron capture therapy, immunoembolizations, and future gene therapy.

Liver metastases from transitional cell carcinoma are lipiodol avid

A case of transitional cell carcinoma of the bladder with symptomatic liver metastases is presented. When conventional chemotherapy failed, a lipiodol CT scan demonstrated avid uptake by the tumours, which has implications for targeted cancer therapy.

Lipiodol accumulation in hepatic hemangioma. Detection with osmium postfixation

Lipiodol has been used to increase the detectability of small primary neoplasms in the liver. We report a patient who was found to have lipiodol deposits in the liver one month after intra-arterial injection. The region was resected, under ultrasound control, because of the impression that the lesion was malignant. The specimen contained two small hemangiomas as well as many small dysplastic nodules (adenomatous hyperplasia) in a noncirrhotic parenchyma. To locate the lipiodol deposit in this case, the tissue was radiographed, postfixed in osmium tetroxide, and embedded in paraffin. Black osmium-stained deposits were found within the cavities of the hemangiomas but not in the dysplastic nodules. Most of the deposits were extracellular multivesiculated bodies with a small focus of lipid droplets engulfed by multinucleated foreign-body type giant cells. This report reinforces that hepatic lipiodol retention is not specific for hepatocellular carcinoma. We present, for the first time, the histologic appearance of lipiodol accumulation in an hemangioma. The value of osmium tetroxide postfixation for the detection of lipiodol is also demonstrated.

Treatment of hepatic-metastatic colorectal cancer with a chemotherapeutic emulsion: interim results of a phase I trial

BACKGROUND

Hepatic arterial infusion of 5-fluoro-2-deoxyuridine (FUdR) is associated with a 60% response rate among previously untreated patients who have hepatic-metastatic colorectal cancer. One obstacle to further dose escalation has been concomitant hepatic toxicity. We are evaluating a FUdR-containing chemotherapeutic emulsion to further dose intensify therapy without associated toxicity.

METHODS

The in vitro pharmacokinetics of the emulsion were determined using high-pressure liquid chromatography (HPLC). The rate at which FUdR is released from emulsion into an overlying aqueous phase was determined in static and dynamic assays. Fifteen patients with hepatic-metastatic colorectal cancer were treated with intrahepatic arterial infusions of emulsion on a phase I dose-escalating clinical protocol. Serum collection determined systemic drug levels using HPLC.

RESULTS

In vitro studies demonstrate that FUdR is slowly released from emulsion into overlying aqueous medium. The emulsion serves as a depot for FUdR. Therapy was well tolerated. Emulsion was sequestered in the liver after infusion in all treated patients.

CONCLUSIONS

This Ethiodol-based, oil-in-water emulsion serves as a sustained-release preparation of FUdR. An Ethiodol-based oil-in-water emulsion is a clinically effective vehicle for delivering FUdR to hepatic-metastatic colorectal tumors.

Preparation and biodistribution of yttrium-90 Lipiodol in rats following hepatic arterial injection

In this study, we labelled Lipiodol with yttrium-90 and analysed the biodistribution in rats after intrahepatic arterial injection. An RP-18 column (E. Merck) was used to separate 90Y from strontium-90. 90Y was retained on the column, which had been pretreated with yttrium-selective extraction reagent, di(2-ethylhexyl) phosphate, while 90Sr was washed out. A hexadentate nitrogen-donor chelating ligand N,N,N',N'-tetrakis(2-benzymidazolylmethyl)-1,2-ethanediamine (EDTB) was synthesized by condensation of 1,2-benzenediamine and ethylene diamine tetra-acetic acid (EDTA). Lipiodol was covalently conjugated with EDTB. The final product was obtained by eluting the retained 90Y from the RP-18 column with EDTB-Lipiodol. Sixteen male rats (Sprague-Dawley) were sacrificed at 1 h, 24 h, 48 h and 72 h (four rats at each time) after injection of approximately 0.1 mCi 90Y-Lipiodol via the hepatic artery. Samples of liver, spleen, muscle, lung, kidney, bone, whole blood and testis were obtained and counted to calculate the tissue concentrations. In addition, labelling efficiency and in vitro stability were determined by ITLC methods. We found that at 1 h after intrahepatic injection, most of the radiotracer was retained in the liver, but it was eliminated gradually over a few days. The radioactivity level in the lung was fair at 1 h and remained at roughly the same level throughout the study. Radioactivity in the kidney and spleen reached a relatively high level at 24 h, but declined rapidly.(ABSTRACT TRUNCATED AT 250 WORDS)

Iodized oil in the treatment of hepatocellular carcinoma

When injected into the hepatic artery the contrast agent Lipiodol (iodized poppy seed oil) is selectively retained by hepatocellular carcinoma (HCC) for a prolonged period of time. Liver computed tomography (CT) performed after Lipiodol angiography is more sensitive than ordinary CT at imaging HCC. Arterial administration of cytotoxic drugs and radioisotopes conjugated to Lipiodol has been shown to be reasonably safe in patients with irresectable HCC. These therapies, often combined with embolization, provide effective palliation, better tumour response and improved survival compared with other available treatments. Their use as a preoperative adjunct to surgical resection of HCC is controversial.

Clinical pharmacokinetic advantages of new drug delivery methods for the treatment of liver tumours

Response rates following systemic chemotherapy for hepatic tumours are disappointing. The drugs used have a narrow therapeutic ratio, which limit the scope for dose escalation of these potentially toxic agents. Therefore, alternative delivery methods that optimise the efficacy of currently available cytotoxic agents have been explored. Several novel approaches have attempted to 'target' treatment so that it reaches the tumour whilst minimising systemic exposure. There is some evidence to suggest that certain agents, including monoclonal antibodies and liposomes, selectively lodge in tumours following intravenous administration. Alternatively, the route of administration may be modified to enhance targeting of the administered drug. Delivery via the hepatic arterial, portal venous, and peritoneal routes as well as drug delivery via direct implantation may provide certain pharmacokinetic advantages. Infusion rates may be adjusted to optimise the pharmacokinetic profile. Chemoembolisation with microspheres, microcapsules or macromolecules might enhance targeting further. Variations in particle characteristics or by modifying hepatic arterial blood flow with vasoactive substances may be used to further refine this technique. The ultimate 'magic bullet', which allows total delivery of treatment to malignant cells whilst eliminating exposure of healthy tissues to these toxic agents, has not been developed as yet. However, currently available techniques allow considerable dose escalation that, whilst not providing a significant survival advantage, certainly improves response rates.

Case report: localization of lipiodol-radioiodine in hepatic metastases from renal cell carcinoma

Lipiodol, an iodinated derivative of poppyseed oil, is selectively retained in hepatocellular carcinoma and has been used as a vehicle to deliver localized doses of chemotherapeutic and radioactive agents to such tumours, thereby reducing the problems of external beam irradiation and the systemic toxicity of chemotherapy. We describe the first reported case where Lipiodol-targeted radiotherapy has been administered to a patient with secondary renal cell carcinoma in the liver. Localization was good and there were no complications. This case suggests that in future such patients may benefit from this therapy for unresectable lesions.