Preparation and in vitro and in vivo evaluations of 10-hydroxycamptothecin liposomes modified with stearyl glycyrrhetinate

Paeoniflorin loaded liposomes modified with glycyrrhetinic acid for liver-targeting: preparation, characterization, and pharmacokinetic study

OBJECTIVE

To enhance the retention times and therapeutic efficacy of paeoniflorin (PF), a liver-targeted drug delivery system has been developed using glycyrrhetinic acid (GA) as a ligand.

SIGNIFICANCE

The development and optimization of GA-modified PF liposomes (GPLs) have shown promising potential for targeted delivery to the liver, opening up new possibilities for liver disease treatment.

METHODS

This study aimed to identify the best prescriptions using single-factor experiments and response surface methodology. The formulation morphology was determined using transmission electron microscopy. Tissue distribution was observed through in vivo imaging, and pharmacokinetic studies were conducted.

RESULTS

The results indicated that GPLs, prepared using the thin film dispersion method and response surface optimization, exhibited well-dispersed and uniformly sized particles. The in vitro release rate of GPLs was slower compared to PF monomers, suggesting a sustained release effect. The liver-targeting ability of GA resulted in stronger fluorescence signals in the liver for targeted liposomes compared to non-targeted liposomes. Furthermore, pharmacokinetic studies demonstrated that GPLs significantly prolonged the residence time of PF in the bloodstream, thereby contributing to prolonged efficacy.

CONCLUSION

These findings suggest that GPLs are more effective than PF monomers in terms of controlling drug release and delivering drugs to specific targets, highlighting the potential of PF as a liver-protective drug.

Preparation, in vitro anti-tumour activity and in vivo pharmacokinetics of RGD-decorated liposomes loaded with shikonin

Shikonin (SHK) has been evidenced to possess effects against various cancer cells. However, poor aqueous solubility and high toxicity restrict its application. In the study, RGD-decorated liposomes loaded with SHK (RGD-Lipo-SHK) were prepared via thin-film hydration method. Characterization and cellular uptake of liposomes was evaluated. Cytotoxicity of blank liposomes and different SHK formulations was measured against breast cancer cells (MDA-MB-231, MCF-7, and MCF-10A). Anti-tumour effects and pharmacokinetic parameters of different SHK formulations were appraised in tumour spheroids and in rat model, respectively. Liposomes displayed a particle size of less than 127 nm with a polydispersity index about 0.21. The encapsulation efficiency was about 91% for SHK, and drug leakage rate of liposomes was less than 6%. RGD-Lipo-SHK showed superior cellular internalization in the αvβ3-positive MDA-MB-231 cells. Blank liposomes had no cytotoxicity to MDA-MB-231 and MCF-7 cells. Howbeit, different SHK formulations obviously inhibited proliferation of MCF-10A cells, especially free SHK. Meanwhile, RGD-Lipo-SHK significantly inhibited growth inhibition of tumour spheroids. The pharmacokinetics study indicated that the peak concentration, area under plasma concentration-time curves, half-life, and mean residence time of RGD-Lipo-SHK distinctly increased compared with those of free SHK. Altogether, these results demonstrated RGD-Lipo-SHK could reduce cytotoxicity, strengthen the antitumor-targeted effect, and prolong circulation time, which provides a foundation for further in vivo experimentations.

MiR-126-Loaded Immunoliposomes against Vascular Endothelial Inflammation In Vitro and Vivo Evaluation

Due to the accompaniment of vascular endothelial inflammation during the occurrence and development of cardiovascular diseases (CVD), treatment modalities against vascular endothelial inflammation have been intensively investigated for CVD prevention and/or treatment. Vascular cell adhesion molecule-1 (VCAM-1) is a typical transmembrane inflammatory protein specifically expressed by inflammatory vascular endothelial. By inhibiting VCAM-1 expression through the miR-126 mediated pathway, vascular endothelial inflammation can be efficiently relieved. Inspired by this, we developed a miR-126-loaded immunoliposome with VCAM-1 monoclonal antibody (VCAM_ab) decorated at its surface. This immunoliposome can be directly targeted to VCAM-1 at the inflammatory vascular endothelial membrane surface and achieve highly efficient treatment against inflammation response. The cellular experiment results showed the immunoliposome had a higher uptake rate towards inflammatory human vein endothelial cells (HUVECs) and can significantly downregulate the VCAM-1 expression level of inflammatory HUVECs. In vivo investigation further demonstrated that this immunoliposome displayed a higher accumulation rate at vascular inflammatory dysfunction sites than its non-VCAM_ab-modified counterpart. These results suggest that this novel nanoplatform can effectively deliver miR-126 to vascular inflammatory endothelium, opening a new avenue for the safe and effective delivery of miRNA for potential clinical application.

A Novel Drug Delivery System: Hyodeoxycholic Acid-Modified Metformin Liposomes for Type 2 Diabetes Treatment

Metformin is a first-line drug for the clinical treatment of type 2 diabetes; however, it always leads to gastrointestinal tolerance, low bioavailability, short half-life, etc. Liposome acts as an excellent delivery system that could reduce drug side effects and promote bioavailability. Hyodeoxycholic acid, a cholesterol-like structure, can regulate glucose homeostasis and reduce the blood glucose levels. As an anti-diabetic active ingredient, hyodeoxycholic acid modifies liposomes to make it overcome the disadvantages of metformin as well as enhance the hypoglycemic effect. By adapting the thin-film dispersion method, three types of liposomes with different proportions of hyodeoxycholic acid and metformin were prepared (HDCA:ME-(0.5:1)-Lips, HDCA:ME-(1:1)-Lips, and HDCA:ME-(2:1)-Lips). Further, the liposomes were characterized, and the anti-type 2 diabetes activity of liposomes was evaluated. The results from this study indicated that three types of liposomes exhibited different characteristics—Excessive hyodeoxycholic acid decreased encapsulation efficiency and drug loading. In the in vivo experiments, liposomes could reduce the fasting blood glucose levels, improve glucose tolerance, regulate oxidative stress markers and protect liver tissue in type 2 diabetic mice. These results indicated that HDCA:ME-(1:1)-Lips was the most effective among the three types of liposomes prepared and showed better effects than metformin. Hyodeoxycholic acid can enhance the hypoglycemic effect of metformin and play a suitable role as an excipient in the liposome.

A "Trojan Horse" Strategy: The Preparation of Bile Acid-Modifying Irinotecan Hydrochloride Nanoliposomes for Liver-Targeted Anticancer Drug Delivery System Study

The bile acid transport system is a natural physiological cycling process between the liver and the small intestine, occurring approximately 6-15 times during the day. There are various bile acid transporter proteins on hepatocytes that specifically recognize bile acids for transport. Therefore, in this paper, a novel liposome, cholic acid-modified irinotecan hydrochloride liposomes (named CA-CPT-11-Lip), was prepared based on the "Trojan horse" strategy. The liposomes preparation process was optimized, and some important quality indicators were investigated. The distribution of irinotecan hydrochloride in mice was then analyzed by high-performance liquid chromatography (HPLC), and the toxicity of liposomes to hepatocellular carcinoma cells (HepG-2) was evaluated in vitro. As a result, CA-CPT-11-Lip was successfully prepared. It was spherical with a particle size of 154.16 ± 4.92 nm, and the drug loading and encapsulation efficiency were 3.72 ± 0.04% and 82.04 ± 1.38%, respectively. Compared with the conventional liposomes (without cholic acid modification, named CPT-11-Lip), CA-CPT-11-Lip had a smaller particle size and higher encapsulation efficiency, and the drug accumulation in the liver was more efficient, enhancing the anti-hepatocellular carcinoma activity of irinotecan hydrochloride. The novel nanoliposome modified by cholic acid may help to expand the application of irinotecan hydrochloride in the treatment of hepatocellular carcinoma and construct the drug delivery system mode of drug liver targeting.

Resveratrol-Loaded Dipalmitoylphosphatidylcholine Liposomal Large Porous Microparticle Inhalations for the Treatment of Bacterial Pneumonia Caused by Acinetobacter baumannii

Background: Acinetobacter baumannii-mediated bacterial pneumonia is a common disease that is harmful to human health. Dipalmitoylphosphatidylcholine (DPPC) is the major lipid component of the pulmonary surfactant (PS) found in the alveolar space; the PS helps to keep surface tension low, which allows for improved oxygen delivery. Resveratrol (RE) is a phytoalexin found in plants that is released in response to injury or infection. The therapeutic effect of Re is limited due to its low solubility and bioavailability. In this study, we report pulmonary delivery of Re-loaded DPPC liposomal large porous microparticles (RDLPMs) for treatment of A. baumannii-induced pneumonia. Methods: Novel RDLPMs were prepared by rotary evaporation and a freeze-drying method in this study. RDLPMs were evaluated by the particle size, electric potential, in vitro release, and particle size distribution. A rat model of A. baumannii-mediated pneumonia was established and used for pharmacodynamic evaluations. Results: The Re-loaded DPPC liposomes (RDLs) consisted of Re/DPPC (1:3, mol/mol) and DPPC/cholesterol (3:1, w/w), with a hydration time of 15 minutes. The RDLs had a high encapsulation efficiency of 69.8% ± 1.6%, a mean size of 191.5 ± 4.5 nm, and a high zeta potential of 12.4 ± 1.5 mV. The RDLPMs were composed of mannitol/large porous microparticles/RDLs (1:4:2, w/w/w) and had a loading efficiency of 2.20% ± 0.24%. The RDLPMs had an aerodynamic diameter (2.73 ± 0.65 μm), a good fluidity (28.30° ± 6.13°), and demonstrated high lung deposition (fine particle fraction = 43.33%). Surprisingly, while penicillin showed better microbial inhibition than the RDLPMs and Re groups in vitro, the RDLPMs were more effective in vivo. Conclusion: The RDLPMs showed good powder properties for pulmonary delivery. The RDLPMs may inhibit the nuclear factor kappa-B pathway and downregulate the expression of cytokines downstream of tumor necrosis factor-α and interleukin-1β. As well as, RDLPMs demonstrated some antibacterial properties against A. baumannii bacteria. Re, when delivered in RDLPMs as a dry powder inhaler, is a promising substitute for antibiotics in the treatment of A. baumannii pneumonia.

Advances in Antitumor Nano-Drug Delivery Systems of 10-Hydroxycamptothecin

10-Hydroxycamptothecin (HCPT) is a natural plant alkaloid from Camptotheca that shows potent antitumor activity by targeting intracellular topoisomerase I. However, factors such as instability of the lactone ring and insolubility in water have limited the clinical application of this drug. In recent years, unprecedented advances in biomedical nanotechnology have facilitated the development of nano drug delivery systems. It has been found that nanomedicine can significantly improve the stability and water solubility of HCPT. NanoMedicines with different diagnostic and therapeutic functions have been developed to significantly improve the anticancer effect of HCPT. In this paper, we collected reports on HCPT nanomedicines against tumors in the past decade. Based on current research advances, we dissected the current status and limitations of HCPT nanomedicines development and looked forward to future research directions.

Excipient-free nanodispersions dominated by amphiphilic glycosides for bioavailability enhancement of hydrophobic aglycones, a case of glycyrrhetinic acid with diammonium glycyrrhizinate

Natural aglycones, a major ingredient accompanied by glycosides in plants, have played an important role in the treatment of various diseases. However, their bioavailability is limited by their poor water solubility. In contrast to previous efforts that required the use of new exotic materials which may raise concerns about biocompatibility, we report the first case of excipient-free nanodispersions in which an insoluble glycyrrhetinic acid (GA) assembled with its amphiphilic parent drug diammonium glycyrrhizinate (DG) into water-dispersible nanodispersions (130.8 nm for particle size and 91.74% for encapsulation efficiency). This strategy largely increased GA's water apparent solubility by hundreds of times to 549.0 μg/mL with a high cumulative dissolution percentage in vitro greater than 80% in 5 min. The study on the formation mechanism showed that the OH, C-O and C=O group stretching peaks shifted in the FTIR spectra of GA-DG nanodispersions, while the COOH peak (δ _COOH 12.19 ppm) disappeared in the ¹H NMR spectrum of GA-DG nanodispersions, indicating that carboxyl groups on GA may interact with the hydroxyl groups of DG in solution. Molecular dynamics simulations suggested that both hydrophobic interactions and hydrogen-bond interactions contribute to the coassembly of GA and DG molecules in aqueous solution. Oral pharmacokinetic studies in rats demonstrated that such nanodispersions have a significant increase in C_max and AUC_0-t of 2.45- and 3.45-fold compared with those for GA, respectively. Therefore, this strategy, employing amphiphilic glycosides as excipients to prepare nanodispersions, not using new materials, paves the way for the further application of hydrophobic aglycone drugs.

Preparation, physicochemical and pharmacological study of 10-hydroxycamptothecin solid dispersion with complexation agent - xylan-nonanoic acid amphiphilic conjugates

An amphiphilic conjugate of carboxymethyl xylan-nonanoic acid (CX-NA) was synthesized with molecular weight of 38.35 kDa, HLB value of 13.59, and critical micelle concentration of 23.17 μg/ml. CX-NA could efficiently encapsulate the model drug of 10-hydroxycamptothecin (HCPT). The drug loaded amphiphilic conjugate could self-assembled to micelles with an average diameter of 110 nm, zeta potential of -42.88 mV, and drug encapsulation efficiency of 79.8%. In vitro experiments confirmed that the drug-loaded micelles exhibited excellent stability and permeability in the intestinal environment. Transport pathway demonstrated that HCPT was uptake by cells through clathrin-mediated endocytosis. Intestinal in situ absorption study further confirmed CX-NA vehicle could enhance HPCT to transport across intestinal epithelial cells in colonic tissues. Furthermore, the formulation showed excellent anti-tumor activity in vitro and improved bioavailability of 3.4 times in vivo as comparing with free HCPT. These findings imply that this amphiphilic conjugate is a potential and promising vehicle for delivery anticancer drug.

In vitro and in vivo Evaluation of a Novel Estrogen-Targeted PEGylated Oxaliplatin Liposome for Gastric Cancer

Background

Chemotherapy is still the main first-line treatment for advanced metastatic gastric cancer, but it has the limitations of serious side effects and drug resistance. Conventional liposome has been substantially used as drug carriers, but they lack targeting character with lower drug bioavailability in tumor tissues. Based on the above problems, a novel estrogen-targeted PEGylated liposome loaded with oxaliplatin (ES-SSL-OXA) was prepared to further improve the metabolic behavior, the safety profile, and the anti-tumor efficacy of oxaliplatin.

Methods

Four kinds of oxaliplatin (OXA) liposomes were prepared by film hydration method. The obtained formulations were characterized in terms of entrapment efficiency (EE), particle size, and so on by HPLC and DLS (dynamic light scanning). The morphology of ES-SSL-OXA was detected by transmission electron microscope (TEM). The in vitro and in vivo targeting effect of ES-SSL-OXA was verified by fluorescence microscopy and in vivo imaging system in gastric cancer cells (SGC-7901) and tumor-bearing athymic mice. The in vitro and in vivo antitumor efficacies of ES-SSL-OXA were investigated on SGC-7901 cells and athymic tumor-bearing mice. Pharmacokinetic, biodistribution, and acute toxicity tests of ES-SSL-OXA were performed on ICR mice.

Results

The ES-SSL-OXA exhibited an average particle size of about 153.37 nm with an encapsulation efficiency of 46.20% and low leakage rates at 4°C and 25°C. In vivo and in vitro targeting study confirmed that ES-SSL-OXA could effectively target the tumor site. The antitumor activity demonstrated the strongest inhibition in tumor growth of ES-SSL-OXA. Pharmacokinetics and acute toxicity study showed that ES-SSL-OXA could significantly improve the metabolic behavior and toxicity profile of oxaliplatin.

Conclusion

In this study, a novel estrogen-targeted long-acting liposomal formulation of OXA was successfully prepared. ES fragment effectively targeted the delivery system to tumor tissues which highly express estrogen receptor, providing a promising therapeutic method for gastric cancer in clinic.

Pulmonary delivery of cationic liposomal hydroxycamptothecin and 5-aminolevulinic acid for chemo-sonodynamic therapy of metastatic lung cancer

Sonodynamic therapy (SDT) has been tried for cancer treatment; however, sonosensitizers are usually administered by injection, leading to low distribution in the tumor tissue and compromised therapeutic effect, even serious side effect. Here, we combined cationic liposomal hydroxycamptothecin (CLH) and 5-aminolevulinic acid (5-ALA) via intratracheal (i.t.) administration for the chemo-sonodynamic (Chemo-SDT) therapy of metastatic lung cancer. CLH was prepared from HCPT and the lipid mixture of soybean lecithin/cholesterol/octadecylamine with a film method. The optimal pre-incubation time of 5-ALA with tumor cells before ultrasound exposure was 4 h, for sake of sonosensitizer accumulation, i.e., protoporphyrin IX, the metabolite of 5-ALA. In vitro studies showed the higher cytotoxicity of Chemo-SDT compared to the other treatments, including i.t. CLH, intravenous (i.v.) CLH, and SDT alone. The combination of pulmonary delivery and Chemo-SDT showed the highest anticancer effect among the treatments on the metastatic lung tumor-bearing mice, which was judged according to the tumor appearance and pathological sections. The major anticancer mechanism of Chemo-SDT included the improved apoptosis of cancer cells and the enhanced production of reactive oxygen species, and more importantly, the synergy of chemotherapy and SDT. Pulmonary delivery of chemotherapeutics and sonosensitizers is a promising strategy for the treatment of lung cancer.

A Novel Drug Delivery System: the Encapsulation of Naringenin in Metal-Organic Frameworks into Liposomes

Poorly water-soluble naringenin (NAR) was selected as a model drug and loaded into the porous MOFs for the construction of NAR@ZIF-8 inclusion complex. By film dispersion method, NAR@ZIF-8 was further encapsulated into liposomes to fabricate a novel drug delivery system. Liposomes and a novel drug delivery system were established. Subsequently, the lipid-drug ratio, phospholipid-cholesterol ratio, and hydration temperature were investigated using the Box-Behnken design based the single factor experiment. The prepared liposomes system showed spherical or quasi-spherical shape, uniform particle size distribution, and complete structure. More specifically, the average particle size was 113.2 ± 1.4 nm, and zeta potential was - 7.536 ± 0.264 mV. Moreover, the drug release behaviors of NAR, NAR@ZIF-8, and NAR@ZIF-8 liposomes were explored in vitro. Compared with free NAR and NAR@ZIF-8 which exhibited a burst drug release, NAR@ZIF-8 liposomes showed a more sustained release behavior with 79.86% drug release in 72 h. In vitro cytotoxicity experiments showed that, compared with free NAR and NAR@ZIF-8, NAR@ZIF-8 liposomes exhibited higher inhibition efficiency on lung adenocarcinoma A549 cells and gastric cancer SGC-7901 cells in a concentration-dependent manner.

Enhanced Stability of the Pharmacologically Active Lactone Form of 10-Hydroxycamptothecin by Self-Microemulsifying Drug Delivery Systems

10-Hydroxycamptothecin (HCPT) is a DNA inhibitor of topoisomerase I and exerts antitumor activities against various types of cancer. However, reversible conversion from a pharmacologically active lactone form to an inactive carboxylate form of HCPT and poor water solubility hamper its clinical applications. To overcome these shortcomings, we designed a fine self-microemulsifying drug delivery system (SMEDDS) for HCPT to effectively protect HCPT in its active lactone form as well as improving dissolution rates. A formulation of HCPT-SMEDDS that contained ethyl oleate, D-α-tocopheryl polyethylene glycol 1000 succinate (TPGS), and polyethylene glycol 400 (PEG400) was optimized by using the central composite design and response surface methodology. Following 1:100 aqueous dilution of the optimized HCPT-SMEDDS, the droplet size of resulting microemulsions was 25.6 ± 0.7 nm, and the zeta potential was - 15.2 ± 0.4 mV. The optimized HCPT-SMEDDS appeared to stabilize the lactone moiety of HCPT with 73.6% being present in the pharmacologically active lactone forms in simulated intestinal fluid, but only 45.7% for free HCPT. Furthermore, the physically stable formulation showed the active lactone form predominated in HCPT-SMEDDS (> 95%) for 6 months under the accelerated storage condition. Meanwhile, the optimized SMEDDS formulation also significantly improved dissolution rates and membrane permeability of the lactone form of HCPT. Therefore, HCPT-SMEDDS involved designing for the ease of manufacture, and provided a potent oral dosage form for preserving its active lactone form as well as enhancing the dissolution rate.

Preparation, Characterization, and in vivo Evaluation of NK4-Conjugated Hydroxycamptothecin-Loaded Liposomes

PURPOSE

In this study, NK4-conjugated hydroxycamptothecin liposomes (NK4-HCPT-Lips) were prepared with the aim of improving drug targeting to the liver.

METHODS

NK4-HCPT-Lips were prepared using the thin-film dispersion method. In vitro antitumor activities were evaluated by MTT assay. HCPT levels in plasma and tissues were determined via high-performance liquid chromatography (HPLC) with camptothecin as the internal standard, and the characteristics, pharmacokinetics, and bio-distribution of NK4-HCPT-Lips were evaluated.

RESULTS

The liposomes showed a regular spherical-shaped morphology, and the entrapment efficiency and drug loading capacity reached 82.5 ± 2.4% and 3.01 ± 0.23%, respectively, with a particle size of 155.6 ± 2.6 nm and a zeta potential of -24.8 ± 3.3 mV. Inhibition effect experiments found that NK4-HCPT-Lips had a good inhibition on the HepG2 cells. Pharmacokinetic studies revealed an increase in the area under the curve and mean residence time as well as a decrease in plasma clearance (p < 0.05) of the NK4-HCPT-Lips compared to those of HCPT liposomes and a commercial HCPT injection. Tissue distribution studies showed that NK4-HCPT-Lips were present at high levels in the liver but were cleared from the kidneys.

CONCLUSION

These results demonstrate that NK4-HCPT-Lips possess excellent liver-targeting attributes, which could enhance the therapeutic effects of drug treatments for hepatic diseases.