ABSTRACT
PURPOSE: The clinical application of gemcitabine (GEM) is limited by its pharmacokinetic properties. The aim of this study was to characterize the stability in circulating plasma, tumor targeting, and payload release of liposome-encapsulated GEM, FF-10832. METHODS: Antitumor activity was assessed in xenograft mouse models of human pancreatic cancer. The pharmacokinetics of GEM and its active metabolite dFdCTP were also evaluated. RESULTS: In mice with Capan-1 tumors, the dose-normalized areas under the curve (AUCs) after FF-10832 administration in plasma and tumor were 672 and 1047 times higher, respectively, than after using unencapsulated GEM. The tumor-to-bone marrow AUC ratio of dFdCTP was approximately eight times higher after FF-10832 administration than after GEM administration. These results indicated that liposomal encapsulation produced long-term stability in circulating plasma and tumor-selective targeting of GEM. In mice with Capan-1, SUIT-2, and BxPC-3 tumors, FF-10832 had better antitumor activity and tolerability than GEM. Internalization of FF-10832 in tumor-associated macrophages (TAMs) was revealed by flow cytometry and confocal laser scanning microscopy, and GEM was efficiently released from isolated macrophages of mice treated with FF-10832. These results suggest that TAMs are one of the potential reservoirs of GEM in tumors. CONCLUSION: This study found that FF-10832 had favorable pharmacokinetic properties. The liposomal formulation was more effective and tolerable than unencapsulated GEM in mouse xenograft tumor models. Hence, FF-10832 is a promising candidate for the treatment of pancreatic cancer.
Subject(s)
Antimetabolites, Antineoplastic/blood , Deoxycytidine/analogs & derivatives , Drug Compounding/methods , Drug Delivery Systems/methods , Pancreatic Neoplasms/blood , Xenograft Model Antitumor Assays/methods , Animals , Antimetabolites, Antineoplastic/administration & dosage , Antimetabolites, Antineoplastic/chemical synthesis , Cell Line, Tumor , Deoxycytidine/administration & dosage , Deoxycytidine/blood , Deoxycytidine/chemical synthesis , Drug Stability , Female , Humans , Liposomes , Male , Mice , Mice, Inbred BALB C , Mice, Inbred ICR , Mice, Nude , Pancreatic Neoplasms/drug therapy , Treatment Outcome , GemcitabineABSTRACT
We previously reported that serofendic acid, a lipophilic extract of fetal calf serum, protects against oxidative stress in primary culture of neonatal rat cardiomyocytes. However, the effect of serofendic acid on myocardial ischemia-reperfusion injury in vivo is yet to be determined. In the present study, we investigated the effect of intravenous administration of serofendic acid on ischemia-reperfusion injury induced by transient occlusion of the left coronary artery in rats. The rat heart was subjected to 25-min ischemia followed by 2-h reperfusion. Bolus intravenous administration of serofendic acid (1-10 mg/kg) given twice reduced the infarct volume in a dose-dependent manner. The protective effect of serofendic acid was abolished by pretreatment with 5-hydroxydecanoate, a blocker of mitochondrial ATP-sensitive potassium channels. For further testing of the protective effect of serofendic acid at the subcellular level, we monitored mitochondrial membrane potential (MMP) in individual cells using real-time two-photon imaging of Langendorff-perfused rat heart. A 25-min no-flow ischemia, followed by reperfusion caused progressive MMP loss. Serofendic acid significantly reduced the number of cells undergoing MMP loss. These results suggest that serofendic acid protected cardiac myocytes against myocardial ischemia-reperfusion injury by preserving the functional integrity of mitochondria.
Subject(s)
Diterpenes/pharmacology , Myocardial Infarction/prevention & control , Myocardial Reperfusion Injury/prevention & control , Myocytes, Cardiac/drug effects , Protective Agents/pharmacology , Animals , Blood Pressure/drug effects , Cytoprotection , Diterpenes/administration & dosage , Dose-Response Relationship, Drug , Injections, Intravenous , Male , Membrane Potential, Mitochondrial/drug effects , Mitochondria, Heart/drug effects , Mitochondria, Heart/metabolism , Mitochondria, Heart/pathology , Myocardial Infarction/metabolism , Myocardial Infarction/pathology , Myocardial Infarction/physiopathology , Myocardial Reperfusion Injury/metabolism , Myocardial Reperfusion Injury/pathology , Myocardial Reperfusion Injury/physiopathology , Myocytes, Cardiac/metabolism , Myocytes, Cardiac/pathology , Potassium Channels/drug effects , Potassium Channels/metabolism , Protective Agents/administration & dosage , Rats, Sprague-Dawley , Time FactorsABSTRACT
This study aimed to quantitatively clarify the critical factors responsible for the superior antitumor efficacy of a liposomal gemcitabine (2,2-difluorodeoxycytidine; dFdC) formulation, FF-10832, compared with dFdC. The underlying hypothesis is the different exposure of tumors to its active metabolite, dFdC triphosphate (dFdCTP), between the two formulations. Therefore, physiologically based pharmacokinetic and pharmacodynamic (PBPK/PD) models for encapsulated and unencapsulated dFdC were constructed considering the tumor dFdCTP concentration as an index of antitumor activity. To estimate drug the parameters, the time profiles of encapsulated and unencapsulated dFdC in the blood and those of dFdC and dFdCTP in tumors were measured following the intravenous bolus administration of FF-10832 or dFdC. dFdC metabolism and transport in the liver S9 fraction and isolated hepatocytes, respectively, were experimentally determined. The tumor growth curve in a mouse xenograft model following the administration of FF10832 and dFdC was also used to construct the PD model. The sensitivity analysis of the PBPK/PD model revealed the critical factors affecting antitumor efficacy, which included the total and intratumor tissue uptake clearances for liposomal formulation and the cytidine deaminase and deoxycytidine deaminase activities in tumors. Thus, these parameters are potential biomarkers for predicting the efficacy of the liposomal formulation of dFdC.
Subject(s)
Cytidine Deaminase , Neoplasms , Humans , Mice , Animals , PolyphosphatesABSTRACT
Serofendic acid is a low-molecular-weight compound extracted from fetal calf serum. We previously reported that intracerebroventricular administration of serofendic acid prevents cerebral ischemia-reperfusion injury. However, the effect of peripheral administration of serofendic acid on cerebral ischemia-reperfusion injury has not been examined. In the present study, we investigated the effect of intravenous administration of serofendic acid against cerebral ischemia-reperfusion injury using transient middle cerebral artery occlusion model rats. Serofendic acid (10mg/kg) administrated three times, including 30min before the onset of ischemia, just after the onset of ischemia and just before reperfusion reduced the infarct volume and improved the neurological dysfunction induced by ischemia-reperfusion without affecting regional cerebral blood flow or physiological parameters. However, there were no protective effects when serofendic acid (30mg/kg) was only administered once at 30min before the onset of ischemia, just after the onset of ischemia, or just before reperfusion. Our results reveal the importance of maintaining the blood concentration of serofendic acid for preventing cerebral ischemia-reperfusion injury.