Antitumor and antimetastasis effects of carboplatin liposomes with polyethylene glycol-2000 on SGC-7901 gastric cell-bearing nude mice

Conventional vs PEGylated loaded liposomal formulations by microfluidics for delivering hydrophilic chemotherapy

Developing drug delivery systems (DDSs) is one of the approaches used to improve cancer treatment, with the main goal of loading cancer drugs into a carrier targeting a specific organ and avoiding the distribution to healthy tissues. Nanoparticles (NPs) have been shown to be one of the optimum carriers that can be used as DDSs. Lipid-based NPs, such as liposomes, have been investigated in the current study due to their low toxicity and ability to carry hydrophilic and hydrophobic molecules. In the current studies, conventional liposomes composed of DPPC, and cholesterol and PEGylated liposomes composed of DPPC, cholesterol, and DSPE-PEG2000 are manufactured and loaded with Carboplatin. The study focused on investigating and comparing the impact of modifying the carboplatin-loaded liposomes with different concentrations of DSPE-PEG2000 on the NP diameter, polydispersity, ζ-potential, encapsulation efficiency (EE%), and drug release. The hydrodynamic microfluidic system was used to investigate any possible improvement in the EE% over other conventional methods. The results showed the microfluidic system's promising effect in enhancing the EE% of the Carboplatin. Moreover, the results showed a smaller diameter and higher stability of the PEGylated liposome. However, conventional liposomes represent better homogeneity and higher encapsulation efficiency for hydrophilic molecules.

Evaluation of anticancer effects of carboplatin-gelatin nanoparticles in different sizes synthesized with newly self-assembly method by exposure to IR light

Carboplatin (CP), a platinum analog, is one of the most widely used chemotherapeutic agents in the treatment of colorectal cancer. Although platinum-based drugs are quite effective in anticancer treatments, their use in a wide spectrum and effective treatment possibilities are limited due to their systemic side effects and drug resistance development. In recent years, studies have focused on increasing the therapeutic efficacy of platinum-based drugs with drug delivery systems. Gelatin, a protein, obtained by the hydrolysis of collagen, is a biocompatible and biodegradable material that can be used in nano drug delivery systems. In this study, CP-loaded gelatin-based NPs (CP-NPs) were exposed to IR light in different temperatures at 30, 35, 40, 45, and 50 °C and characterized by FESEM-EDX, FTIR, UV–Vis, DLS. Accordingly, we synthesized gelatin-based CP-NPs of different sizes between 10–290 nm by exposure to IR. We found that CP-NPs-50, 16 nm nano-sized, obtained at 50 °C had the most cytotoxicity and was 2.2 times more effective than the free drug in HCT 116 colon cancer cells. Moreover, we showed that the cytotoxicity of CP-NPs-50 in normal HUVEC cells was lower. Additionally, we demonstrated that CP-NPs enhanced apoptotic activity while not developing MDR1-related resistance in colon cancer cells. In this study, for the first time drug loaded gelatin-based nanoparticles were synthesized in different sizes with a newly self-assembly method by exposing them to infrared light at different temperatures and their anticancer effects were evaluated subsequently.

Liposomal formulations of carboplatin injected by convection-enhanced delivery increases the median survival time of F98 glioma bearing rats

BACKGROUND

Effectiveness of chemotherapy for treating glioblastoma (GBM) brain tumors is hampered by the blood-brain barrier which limits the entry into the brain of most drugs from the blood. To bypass this barrier, convection-enhanced delivery (CED) was proposed to directly inject drugs in tumor. However, the benefit of CED may be hampered when drugs diffuse outside the tumor to then induce neurotoxicity. Encapsulation of drugs into liposome aims at increasing tumor cells specificity and reduces neurotoxicity. However, the most appropriate liposomal formulation to inject drugs into brain tumor by CED still remains to be determined. In this study, four liposomal carboplatin formulations were prepared and tested in vitro on F98 glioma cells and in Fischer rats carrying F98 tumor implanted in the brain. Impact of pegylation on liposomal surface and relevance of positive or negative charge were assessed.

RESULTS

The cationic non-pegylated (L1) and pegylated (L2) liposomes greatly improved the toxicity of carboplatin in vitro compared to free carboplatin, whereas only a modest improvement and even a reduction of efficiency were measured with the anionic non-pegylated (L3) and the pegylated (L4) liposomes. Conversely, only the L4 liposome significantly increased the median survival time of Fisher rats implanted with the F98 tumor, compared to free carboplatin. Neurotoxicity assays performed with the empty L4' liposome showed that the lipid components of L4 were not toxic. These results suggest that the positive charge on liposomes L1 and L2, which is known to promote binding to cell membrane, facilitates carboplatin accumulation in cancer cells explaining their higher efficacy in vitro. Conversely, negatively charged and pegylated liposome (L4) seems to diffuse over a larger distance in the tumor, and consequently significantly increased the median survival time of the animals.

CONCLUSIONS

Selection of the best liposomal formulation based on in vitro studies or animal model can result in contradictory conclusions. The negatively charged and pegylated liposome (L4) which was the less efficient formulation in vitro showed the best therapeutic effect in animal model of GBM. These results support that relevant animal model of GBM must be considered to determine the optimal physicochemical properties of liposomal formulations.

Development of a carboplatin derivative conjugated with a collagen-like triple-helical peptide

AIM

The development of a platinum anticancer agent that has improved efficacy by efficient delivery to a tumor and that suppresses side effects has been investigated. Arginine-rich triple-helical peptides are promising drug carriers because of their stability in body fluids and cell-penetrating activity.

RESULTS

We synthesized a carboplatin derivative conjugated with an arginine-rich triple-helical peptide. This derivative released platinum under acidic conditions or in the presence Cl^- ions. Administration of this derivative to P388 tumor-bearing mice showed comparable survival rates to twice the dose of carboplatin, which was attributed to a longer mean residence time by pharmacokinetics analysis.

CONCLUSION

The collagen-like triple-helical peptide was an efficient carrier of a platinum anticancer agent because of a modification to its pharmacokinetic profile.

A simple passive equilibration method for loading carboplatin into pre-formed liposomes incubated with ethanol as a temperature dependent permeability enhancer

A passive equilibration method which relies on addition of candidate drugs to pre-formed liposomes is described as an alternative method for preparing liposome encapsulated drugs. The method is simple, rapid and applicable to liposomes prepared with high (45mol%) or low (<20mol%) levels of cholesterol. Passive equilibration is performed in 4-steps: (i) formation of liposomes, (ii) addition of the candidate drug to the liposomes in combination with a permeability enhancing agent, (iii) incubation at a temperature that facilitates diffusion of the added compound across the lipid bilayer, and (iv) quenching the enhanced membrane permeability by reduction in temperature and/or removal of the permeabilization enhancer. The method is fully exemplified here using ethanol as the permeabilization enhancer and carboplatin (CBDCA) as the drug candidate. It is demonstrated that ethanol can be added to liposomes prepared with 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC) and Cholesterol (Chol) (55:45mol ratio) in amounts up to 30% (v/v) with no change in liposome size, even when incubated at temperatures>60°C. Super-saturated solutions of CBDCA (40mg/mL) can be prepared at 70°C and these are stable in the presence of ethanol even when the temperature is reduced to <30°C. maximum CBDCA encapsulation is achieved within 1h after the CBDCA solution is added to pre-formed DSPC/Chol liposomes in the presence of 30% (v/v) ethanol at 60°C. When the pre-formed liposomes are mixed with ethanol (30% v/v) at or below 40°C, the encapsulation efficiency is reduced by an order of magnitude. The method was also applied to liposomes prepared from other compositions include a cholesterol free formulations (containing 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[carboxy(polyethylene glycol)-2000] (DSPE-PEG₂₀₀₀)) and a low Chol (<20mol%) formulations prepared with the distearoyl-sn-glycero-3-phospho-(1'-rac-glycerol) DSPG)). The cytotoxic activity of CBDCA was unaffected when prepared in this manner and two of the resultant formulations exhibited good stability in vitro and in vivo. The cytotoxic activity of CBDCA was unaffected when prepared in this manner and the resultant formulations exhibited good stability in vitro and in vivo. Pharmacokinetics studies in CD-1 mice indicated that the resulting formulations increased the circulation half life of the associated CBDCA significantly (AUC_0-24h of CBDCA=0.016μg·hr/mL; AUC_0-24h of the DSPC/Chol CBDCA formulation=1014.0μg·hr/mL and AUC_0-24h of the DSPC/DSPG/Chol CBDCA formulation=583.96μg·hr/mL). Preliminary efficacy studies in Rag-2M mice with established subcutaneous H1975 and U-251 tumors suggest that the therapeutic activity of CBDCA is improved when administered in liposomal formulations. The encapsulation method described here has not been disclosed previously and will have broad applications to drugs that would normally be encapsulated during liposome manufacturing.

Exploiting developments in nanotechnology for the preferential delivery of platinum-based anti-cancer agents to tumours: targeting some of the hallmarks of cancer

Platinum drugs as anti-cancer therapeutics are held in extremely high regard. Despite their success, there are drawbacks associated with their use; their dose-limiting toxicity, their limited activity against an array of common cancers and patient resistance to Pt-based therapeutic regimes. Current investigations in medicinal inorganic chemistry strive to offset these shortcomings through selective targeting of Pt drugs and/or the development of Pt drugs with new or multiple modes of action. A comprehensive overview showcasing how liposomes, nanocapsules, polymers, dendrimers, nanoparticles and nanotubes may be employed as vehicles to selectively deliver cytotoxic Pt payloads to tumour cells is provided.

Preparation, Characterization and Cytotoxic Effects of Pegylated Nanoliposomal Containing Carboplatin on Ovarian Cancer Cell Lines

Carboplatin is a chemotherapeutic agent used against various malignancies such as ovarian carcinoma. The aim of this study is to improve the therapeutic efficacy of carboplatin using pegylated liposomal nanocarriers. Nanoparticles were synthesized using thin film hydration technique and characterized for shape morphology, particle size, zeta potential and drug-release properties. In the next step, A2780S and A2780CP ovarian cancer cell lines were used to determine the efficacy of nanodrug by MTT assay. The particle size and zeta potential of nanodrug were measured 244.3 ± 19.6 nm and -22.9 ± 1.7 mV, respectively. High encapsulation capacity (78.6 ± 3.7 %) confirmed the efficiency of technique. The cytotoxicity results also showed that nanodrug compared to free drug improve the efficacy of carboplatin against both A2780S (P < 0.01) and A2780CP (P < 0.05) cell lines. In conclusion, the findings of our study suggested pegylated liposomal nanocarriers are proper for carboplatin delivery to ovarian cancer cell lines A2780S and A2780CP.