Stability and degradation kinetics of etoposide‐loaded parenteral lipid emulsion

Formulation and Physicochemical and Biological Characterization of Etoposide-Loaded Submicron Emulsions with Biosurfactant of Sophorolipids

Etoposide (ETO), a traditional anticancer chemotherapeutic agent, is commercialized in oral soft gelatin capsules and non-aqueous parenteral solutions form. Novel formulation application and new excipients exploration are needed to improve the water-solubility and comfort of the drug administration. In the present study, novel etoposide-loaded submicron emulsions (ESE) with the biosurfactants of acidic sophorolipid (ASL) and lactonic sophorolipid (LSL) instead of the chemical surfactant of Tween-80 were prepared and characterized. Firstly, parameters of medium-chain triglyceride: long-chain triglyceride (MCT:LCT), lecithin concentration, homogenization pressure and cycle, and type and concentration of surfactants were investigated to optimize the formation of ESEs. Then the physicochemical properties, antitumor activity, stability, and security of ESEs were compared. The results showed that ASL performed the best properties and activities than Tween-80 and LSL in ESE formation. ASL-ESE showed higher drug loading capacity, slower release rate, and significantly increased antitumor activity against ovarian cancer cell line A2780 via apoptosis than Tween-ESE and commercial ETO injection. Besides, both ASL-ESE and Tween-ESE caused no hemolysis, and the safe dose of ASL was 2.14-fold that of Tween-80 in the hemolysis test, making ASL more reliable for drug delivery applications. Furthermore, ASL-ESE exhibited equivalent long-term and autoclaving stability to Tween-ESE. These results thus suggested the excellent competences of ASL in ESE formation, efficacy enhancement, and safety improvement.

Optimization and evaluation of lipid emulsions for intravenous co-delivery of artemether and lumefantrine in severe malaria treatment

Parenteral therapy for severe and complicated malaria is necessary, but currently available parenteral antimalarials have their own drawbacks. As for recommended artemisinin-based combination therapy, antimalarial artemether and lumefantrine are limited in parenteral delivery due to their poor water solubility. Herein, the aim of this study was to develop the lipid-based emulsions for intravenous co-delivery of artemether and lumefantrine. The lipid emulsion was prepared by high-speed shear and high-pressure homogenization, and the formulations were optimized mainly by monitoring particle size distribution under autoclaved conditions. The final optimal formulation was with uniform particle size distribution (~ 220 nm), high encapsulation efficiency (~ 99%), good physiochemical stability, and acceptable hemolysis potential. The pharmacokinetic study in rats showed that C_max of artemether and lumefantrine for the optimized lipid emulsions were significantly increased than the injectable solution, which was critical for rapid antimalarial activity. Furthermore, the AUC_0-t of artemether and lumefantrine in the lipid emulsion group were 5.01- and 1.39-fold of those from the solution, respectively, suggesting enhanced bioavailability. With these findings, the developed lipid emulsion is a promising alternative parenteral therapy for the malaria treatment, especially for severe or complicated malaria.

Etoposide-Loaded Poly(Lactic-co-Glycolic Acid) Intravitreal Implants: In Vitro and In Vivo Evaluation

Etoposide-loaded poly(lactic-co-glycolic acid) implants were developed for intravitreal application. Implants were prepared by a solvent-casting method and characterized in terms of content uniformity, morphology, drug-polymer interaction, stability, and sterility. In vitro drug release was investigated and the implant degradation was monitored by the percent of mass loss. Implants were inserted into the vitreous cavity of rabbits' eye and the in vivo etoposide release profile was determined. Clinical examination and the Hen Egg Test-Chorioallantoic Membrane (HET-CAM) method were performed to evaluate the implant tolerance. The original chemical structure of the etoposide was preserved after incorporation in the polymeric matrix, which the drug was dispersed uniformly. In vitro, implants promoted sustained release of the drug and approximately 57% of the etoposide was released in 50 days. In vivo, devices released approximately 63% of the loaded drug in 42 days. Ophthalmic examination and HET-CAM assay revealed no evidence of toxic effects of implants. These results tend to show that etoposide-loaded implants could be potentially useful as an intraocular etoposide delivery system in the future.

A stable and practical etoposide-containing intravenous long-/medium-chain triglycerides-based lipid emulsion formulation: pharmacokinetics, biodistribution, toxicity, and antitumor efficacy

OBJECTIVES

This work aimed to evaluate pharmacokinetics, biodistribution, toxicity, and antitumor activities of a highly stable long-/medium-chain triglycerides (LCT/MCT)-based etoposide parenteral emulsion (EPE) in comparison to etoposide parenteral solution (EPS).

METHODS

Using high-pressure homogenization method, EPE was prepared and sterilized at 121°C for 10 min by autoclaving. The biological samples were analyzed using the UPLC-ESI-MS/MS method.

RESULTS

Superior stability of EPE was verified with no significant changes in physicochemical properties in the accelerating and long-term stability tests. Similar pharmacokinetic behavior in beagle dogs was obtained and the AUC 0 - 12h values were 1196.73 ± 320.85 and 1505.56 ± 617.93 µg.h/L for EPE and EPS (p > 0.5), respectively. Likewise, no remarkable difference in biodistribution profiles in mice was found for both formulations. Safety assessment studies including hemolysis test, rabbit ear vein test and injection anaphylaxis were undertaken and the EPE was proven to be safe for intravenous administration. Specifically, after consecutive 12 weeks administration in rats, systematic and local toxicity induced by EPE were alleviated relative to that of EPS. Furthermore, significant and comparable antitumor activities to EPS were also demonstrated by EPE with tumor suppression rate (TSR) of 66.63, 55.94, and 60.16% against H460, Hep G2, and BCAP-37 human cancer cell lines in nude mice at the dose of 15 mg/kg, respectively.

CONCLUSION

These results suggest that this LCT/MCT-based lipid emulsion is a promising alternative intravenous carrier for etoposide with high stability, improved convenience, alleviated toxicity, and noncompromised antitumor efficacy.

Reformulation of etoposide with solubility-enhancing rubusoside

Etoposide (ETO), a widely used anti-cancer drug, is constrained by its low aqueous solubility and by side effects from both the drug and its solubilizing excipients. In this study, a recently discovered natural solubilizer rubusoside (RUB) was used to achieve the solubilization of ETO. Dynamic light scattering and freeze-fracture transmission electron microscopy studies showed that ETO and RUB formed ETO-RUB nanoparticles (∼6 nm in diameter). The powder of ETO-RUB nanoparticles was completely reconstitutable in water and remained stable in this solution at 25 and 37°C for at least 24h. Under other physiologic conditions, ETO solution was clear and free of precipitation at 25°C, but underwent various structural transformations. In PBS and simulated intestinal fluid, RUB-solubilized ETO underwent epimerization and equilibrated to cis-ETO. In simulated gastric fluid, RUB-solubilized ETO degraded to 4'-demethylepipodophyllotoxin-beta-d-glucoside and 4'-demethylepipodophyllotoxin. Higher temperatures favored epimerization or degradation. Furthermore, a side-by-side comparison with DMSO-solubilized ETO confirmed that the RUB-solubilized ETO showed no significant differences in cytotoxicity in colon, breast and prostate cancer cell lines. RUB effectively solubilized and stabilized etoposide, which sets the stage for further toxicology, bioavailability, and efficacy investigations.

A validated stability-indicating LC method for estimation of etoposide in bulk and optimized self-nano emulsifying formulation: Kinetics and stability effects

The present investigation was aimed to establish a validated stability-indicating liquid chromatographic method for the estimation of etoposide (ETP) in bulk drug and self-nano emulsifying formulation. ETP was successfully separated from the degradation products formed under stress conditions on LiChrospher 100 C18 reverse-phase column (a 250 mm × 4.6 mm i.d., 5-μm particle size) using 55:45 (v/v) acetonitrile-phosphate buffer saline (pH 4.5) as the mobile phase, at a flow rate of 1.0 mL min(-1) and detection at 283 nm. The response was a linear function of analyte concentration (R(2) > 0.9997) over the concentration range of 0.05-50 μg mL(-1). The method was validated for precision, accuracy, robustness, sensitivity and specificity. The % recovery of ETP at three different levels (50%, 100% and 150%) ranged between 93.84% and 100.06% in optimized self-nano emulsifying formulation, Etosid® soft-gelatin capsule and Fytosid® injection. First-order degradation kinetics of ETP were observed under acidic and alkaline conditions. The method was also applied for the stability assessment of self-nano emulsifying formulation under accelerated conditions, the formulation was found to be stable at all storage conditions with the shelf-life of 2.37 years at 25 °C. The method holds promise for routine quality control of ETP in bulk, pharmaceutical formulations as well as in stability-indicating studies.

Analysis of anticancer drugs: a review

In the last decades, the number of patients receiving chemotherapy has considerably increased. Given the toxicity of cytotoxic agents to humans (not only for patients but also for healthcare professionals), the development of reliable analytical methods to analyse these compounds became necessary. From the discovery of new substances to patient administration, all pharmaceutical fields are concerned with the analysis of cytotoxic drugs. In this review, the use of methods to analyse cytotoxic agents in various matrices, such as pharmaceutical formulations and biological and environmental samples, is discussed. Thus, an overview of reported analytical methods for the determination of the most commonly used anticancer drugs is given.

Formulation development of parenteral phospholipid-based microemulsion of etoposide

The aim of the present study was to investigate the potential of a phospholipid-based microemulsion formulation for parenteral delivery of anticancer drug, etoposide. The microemulsion area was identified by constructing pseudoternary phase diagrams. The prepared microemulsions were subjected to different thermodynamic stability tests. The microemulsion formulations that passed thermodynamic stability tests were characterized for optical birefringence, droplet size, viscosity measurement, and pH measurements. To assess the safety of the formulations for parenteral delivery, the formulation was subjected to compatibility studies with various intravenous infusions and in vitro erythrocyte toxicity study. The developed formulation was found to be robust and safe for parenteral delivery.