Irinophore C™, a lipid nanoparticle formulation of irinotecan, abrogates the gastrointestinal effects of irinotecan in a rat model of clinical toxicities

Optimized rat models better mimic patients with irinotecan-induced severe diarrhea

Irinotecan-induced severe diarrhea (IISD) not only limits irinotecan's application but also significantly affects patients' quality of life. However, existing animal models often inadequately represent the dynamics of IISD development, progression, and resolution across multiple chemotherapy cycles, yielding non-reproducible and highly variable response with limited clinical translation. Our studies aim to establish a reproducible and validated IISD model that better mimics the pathophysiology progression observed in patients, enhancing translational potential. We investigated the impact of dosing regimens (including different dose, infusion time, and two cycles of irinotecan administration), sex, age, tumor-bearing conditions, and irinotecan formulation on the IISD incidence and severity in mice and rats. Lastly, we investigated above factors' impact on pharmacokinetics of irinotecan, intestinal injury, and carboxylesterase activities. In summary, we successfully established a standard model establishment procedure for an optimized IISD model with highly reproducible severe diarrhea incidence rate (100%) and a low mortality rate (11%) in F344 rats. Additionally, the rats tolerated at least two cycles of irinotecan chemotherapy treatment. In contrast, the mouse model exhibited suboptimal IISD incidence rates (60%) and an extremely high mortality rate (100%). Notably, dosing regimen, age and tumor-bearing conditions of animals emerged as critical factors in IISD model establishment. In conclusion, our rat IISD model proves superior in mimicking pathophysiology progression and characteristics of IISD in patients, which stands as an effective tool for mechanism and efficacy studies in future chemotherapy-induced gut toxicity research.

Metal complex-based liposomes: Applications and prospects in cancer diagnostics and therapeutics

Metal complexes are of increasing interest as pharmaceutical agents in cancer diagnostics and therapeutics, while some of them suffer from issues such as limited water solubility and severe systemic toxicity. These drawbacks severely hampered their efficacy and clinical applications. Liposomes hold promise as delivery vehicles for constructing metal complex-based liposomes to maximize the therapeutic efficacy and minimize the side effects of metal complexes. This review provides an overview on the latest advances of metal complex-based liposomal delivery systems. First, the development of metal complex-mediated liposomal encapsulation is briefly introduced. Next, applications of metal complex-based liposomes in a variety of fields are overviewed, where drug delivery, cancer imaging (single photon emission computed tomography (SPECT), positron emission tomography (PET), and magnetic resonance imaging (MRI)), and cancer therapy (chemotherapy, phototherapy, and radiotherapy) were involved. Moreover, the potential toxicity, action of toxic mechanisms, immunological effects of metal complexes as well as the advantages of metal complex-liposomes in this content are also discussed. In the end, the future expectations and challenges of metal complex-based liposomes in clinical cancer therapy are tentatively proposed.

Geniposide-Loaded Liposomes for Brain Targeting: Development, Evaluation, and In Vivo Studies

Geniposide (GE) possesses excellent neuroprotective effects but with poor brain targeting and short half-life. Liposome was considered to have great potential for brain diseases. Therefore, this research aimed to develop a geniposide liposome (GE-LP) as a brain delivery system for cerebral ischemia reperfusion injury (CIRI) therapy and evaluate its characterization, pharmacokinetics, brain targeting, and neuroprotective effects in vivo. Then, a reverse-phase evaporation method was applied to develop the GE-LP and optimize the formulation. Notably, the GE-LP had suitable size, which was 223.8 nm. Subsequently, the pharmacokinetic behavior of GE solution and GE-LP in mice plasma was investigated, and the brain targeting was also researched. The results showed that GE in plasma of GE-LP displayed three folds longer distribution half-life and a higher bioavailability and brain targeting compared to GE solution. In vivo neuroprotective effects was evaluated through the middle cerebral artery occlusion (MCAO) rat model, and GE-LP exhibited a stronger tendency in preventing the injury of CIRI, which can significantly improve neurological deficits. Overall, this study demonstrates GE-LP as a new formulation with ease of preparation, sustained release, and high brain targeting, which has significant development prospects on CIRI; this is expected to improve the efficacy of GE and reduce the frequency of administration.

Phytochemicals in Chemoprevention: A Cost-Effective Complementary Approach

Cancer is one of the leading causes of death across the world. Although conventional cancer treatments such as chemotherapy and radiotherapy have effectively decreased cancer progression, they come with many dose-limiting side-effects. Phytochemicals that naturally occur in spices, fruits, vegetables, grains, legumes, and other common foods are surprisingly effective complements to conventional cancer treatments. These biologically active compounds demonstrate anticancer effects via cell signaling pathway interference in cancerous cells. In addition, phytochemicals protect non-cancerous cells from chemotherapy-induced side-effects. This paper addresses the not only the potential of phytochemicals quercetin, isoflavones, curcumin, catechins, and hesperidin in terms of cancer treatment and protection against side-effects of chemotherapy, but also methods for increasing phytochemical bioavailability.

Characterization of a liposomal copper(II)-quercetin formulation suitable for parenteral use

Quercetin (3,3',4',5,7-pentahydroxyflavone) is a naturally derived flavonoid that is commonly found in fruits and vegetables. There is mounting evidence to suggest that quercetin has potential anticancer effects and appears to interact synergistically when used in combination with approved chemotherapeutic agents such as irinotecan and cisplatin. Unfortunately, quercetin has shown limited clinical utility, partly due to low bioavailability related to its poor aqueous solutions (< 10 μg/mL). In this study, liposomal formulations of quercetin were developed by exploiting quercetin's ability to bind copper. Quercetin powder was added directly to pre-formed copper-containing liposomes (2-distearoyl-sn-glycero-3-phosphocholine (DSPC) and cholesterol (CHOL) (55:45 M ratio)). As a function of time and temperature, the formation of copper-quercetin was measured. Using this methodology, a final quercetin-to-lipid (mol:mol) ratio of 0.2 was achievable and solutions containing quercetin at concentrations of > 5 mg/mL were attained, representing at least a > 100-fold increase in apparent solubility. The resulting formulation was suitable for intravenous dosing with no overt toxicities when administered at doses of 50 mg/kg in mice. Pharmacokinetic studies demonstrated that the copper-quercetin formulations had an AUC_0-24H of 8382.1 μg h/mL when administered to mice at 50 mg/kg. These studies suggested that quercetin (not copper-quercetin) dissociates from the liposomes after administration. The resulting formulation is suitable for further development and also serves as a proof-of-concept for formulating other flavonoids and flavonoid-like compounds. Given that quercetin exhibits an IC₅₀ of >10 μM when tested against cancer cell lines, we believe that the utility of this novel quercetin formulation for cancer indications will ultimately be as a component of a combination product.

Lipid-based nanoparticle formulations for small molecules and RNA drugs

Introduction: Liposomes and lipid-based nanoparticles (LNPs) effectively deliver cargo molecules to specific tissues, cells, and cellular compartments. Patients benefit from these nanoparticle formulations by altered pharmacokinetic properties, higher efficacy, or reduced side effects. While liposomes are an established delivery option for small molecules, Onpattro® (Sanofi Genzyme, Cambridge, MA) is the first commercially available LNP formulation of a small interfering ribonucleic acid (siRNA). Areas covered: This review article summarizes key features of liposomal formulations for small molecule drugs and LNP formulations for RNA therapeutics. We describe liposomal formulations that are commercially available or in late-stage clinical development and the most promising LNP formulations for ASOs, siRNAs, saRNA, and mRNA therapeutics. Expert opinion: Similar to liposomes, LNPs for RNA therapeutics have matured but still possess a niche application status. RNA therapeutics, however, bear an immense hope for difficult to treat diseases and fuel the imagination for further applications of RNA drugs. LNPs face similar challenges as liposomes including limitations in biodistribution, the risk to provoke immune responses, and other toxicities. However, since properties of RNA molecules within the same group are very similar, the entire class of therapeutic molecules would benefit from improvements in a few key parameters of the delivery technology.

Liposomal OTS964, a TOPK inhibitor: a simple method to estimate OTS964 association with liposomes that relies on enhanced OTS964 fluorescence when bound to albumin

OTS964 is an inhibitor of T-lymphokine-activated killer cell-originated protein kinase (TOPK), a protein kinase important for mitosis and highly expressed in ovarian and lung cancers. This compound demonstrated potent anti-proliferative activity in a panel of cell lines positive for TOPK; however, when administered to mouse xenograft models, adverse hematopoietic toxicities were observed. To overcome this problem, OTS964 was encapsulated into liposomes and a liposomal formulation of OTS964 is now considered a lead candidate for clinical development. To support clinical development of this formulation, it is critically important to define assays that can easily distinguish between free and liposomal OTS964. Here, we develop a new assay to determine liposomal OTS964 encapsulation (percentage of drug associated with the liposomes) and OTS964 that is dissociated from the liposomes (percentage of drug released from liposomes) by monitoring the enhanced OTS964 fluorescence after its binding to albumin. The optical properties of OTS964 were investigated and three absorbance peaks were identified (235 nm, 291 nm, and 352 nm). Fluorescence was observed at 350 nm (excitation) and 470 nm (emission). Interestingly, the fluorescence of OTS964 increased 18-fold in the presence of serum proteins and more specifically albumin. This phenomenon was used to discriminate between the amounts of drug associated with the liposomes or released from the liposomes. Controls consisting of liposomal OTS964 permeabilized with saponins or octyl glucopyranoside served to confirm that drug release could be monitored by albumin-associated increases in fluorescence. The OTS964 liposomal formulation proved to be very stable with less than 10% release after 4 days in phosphate-buffered saline at 37 °C. The quantity of drug associated with the liposomal surface but not inside the liposomes could also be estimated using this approach. These studies present a novel approach to characterize liposomal release of OTS964, in real time and in a non-invasive manner while acquiring additional information about the spatial distribution of liposomal drug.

Prodrugs in combination with nanocarriers as a strategy for promoting antitumoral efficiency

Prodrug entrapment into nanocarriers for tumor delivery is a strategy to achieve a valid therapy with high efficiency. The prodrug contains anticancer agents conjugating with functional moieties or ligands so that the active component is released after metabolism in the body or tumor. The advantages of nanosystems for loading prodrugs include high loading, increased prodrug stability, improved bioavailability and enhanced targeting to tumor cells. In the present article, we introduce the prodrug delivery approaches according to nanomedicine and the recent advances in prodrug-loaded nanocarriers. First, we discuss the conceptional design of combined prodrugs and nanocarriers in response to the obstruction in anticancer therapy. Then we describe the cases of prodrug-loaded nanoparticles for cancer treatment during the past 5 years.

Irinotecan and Δ⁸-Tetrahydrocannabinol Interactions in Rat Liver: A Preliminary Evaluation Using Biochemical and Genotoxicity Markers

There is growing interest regarding the use of herbal preparations based on Cannabis sativa for medicinal purposes, despite the poorly understood interactions of their main constituent Δ⁸-tetrahydrocannabinol (THC) with conventional drugs, especially cytostatics. The objective of this pilot study was to prove whether the concomitant intake of THC impaired liver function in male Wistar rats treated with the anticancer drug irinotecan (IRI), and evaluate the toxic effects associated with this exposure. IRI was administered once intraperitoneally (at 100 mg/kg of the body weight (b.w.)), while THC was administered per os repeatedly for 1, 3, and 7 days (at 7 mg/kg b.w.). Functional liver impairments were studied using biochemical markers of liver function (aspartate aminotransferase-AST, alanine aminotransferase-ALP, alkaline phosphatase-AP, and bilirubin) in rats given a combined treatment, single IRI, single THC, and control groups. Using common oxidative stress biomarkers, along with measurement of primary DNA damage in hepatocytes, the degree of impairments caused at the cellular level was also evaluated. THC caused a time-dependent enhancement of acute toxicity in IRI-treated rats, which was confirmed by body and liver weight reduction. Although single THC affected ALP and AP levels more than single IRI, the levels of liver function markers measured after the administration of a combined treatment mostly did not significantly differ from control. Combined exposure led to increased oxidative stress responses in 3- and 7-day treatments, compared to single IRI. Single IRI caused the highest DNA damage at all timepoints. Continuous 7-day oral exposure to single THC caused an increased mean value of comet tail length compared to its shorter treatments. Concomitant intake of THC slightly affected the levels of IRI genotoxicity at all timepoints, but not in a consistent manner. Further studies are needed to prove our preliminary observations, clarify the underlying mechanisms behind IRI and THC interactions, and unambiguously confirm or reject the assumptions made herein.

Rational design of polysorbate 80 stabilized human serum albumin nanoparticles tailored for high drug loading and entrapment of irinotecan

Human serum albumin (HSA) nanoparticles are considered to be versatile carrier of anticancer agents in efficiently delivering the drug to the tumor site without causing any toxicity. The aim of the study was to develop stable HSA nanoparticles (NPs) of drug irinotecan (Iro) having slightly water solubility and moderate HSA binding. A novel strategy of employing a hydrophilic non-ionic surfactant polysorbate 80 which forms protein-polysorbate 80 complex with increased affinity and improvement in Iro-HSA binding has been used to maximize the loading and entrapment efficiency of Iro in HSA-NPs. Bespoke nanoparticles with entrapment efficiency (79.09%) and drug loading of 9.62% could be achieved with spherical shape and particle size of 77.38 nm, 0.290 polydispersity index and -23.7 mv Zeta potential. The drug entrapment in nanoparticles was confirmed by Differential Scanning Calorimeter, Fourier Transformation Infrared Spectroscopy and Fluorescence Spectroscopy. In vitro release of Iro from NPs showed biphasic-release with initial burst followed by prolonged release upto 24 h. The short-term stability investigation of nanodispersion showed no significant changes in physicochemical properties of NPs. Long-term studies on freeze dried Iro-HSA-NPs indicated good stability of NPs up to 12 months. This is the first report for efficient fabrication of Iro delivery system based on HSA nanoparticles.

Irinotecan Liposome Injection

Each month, subscribers to The Formulary Monograph Service receive 5 to 6 well-documented monographs on drugs that are newly released or are in late phase 3 trials. The monographs are targeted to Pharmacy & Therapeutics Committees. Subscribers also receive monthly 1-page summary monographs on agents that are useful for agendas and pharmacy/nursing in-services. A comprehensive target drug utilization evaluation/medication use evaluation (DUE/MUE) is also provided each month. With a subscription, the monographs are are available online to subscribers. Monographs can be customized to meet the needs of a facility. Through the cooperation of The Formulary, Hospital Pharmacy publishes selected reviews in this column. For more information about The Formulary Monograph Service, contact Wolters Kluwer customer service at 866-397-3433. The February 2017 monograph topics are bezlotoxumab, binimetinib, broadalumab, deuterabenazine, prasterone vaginal, and valbenazine. The DUE is on bezlotoxumab.