Nanoliposomes as drug delivery systems: safety concerns.

The review highlights the safety issues of drug delivery systems based on liposomes. Due to their small sizes (about 80-120 nm, sometimes even smaller), phospholipid nanoparticles interact intensively with living systems during parenteral administration. This interaction significantly affects both their transport role and safety; therefore, special attention is paid to these issues. The review summarises the data on the basic factors affecting the safety of nanoliposomes: composition, size, surface charge, stability, the release of an incorporated drug, penetration into tissues, interaction with the complement system. Attention is paid to the authors' own research of unique phospholipid nanoparticles with a diameter of 20-30 nm. The influence of technological processes of nanoliposome production on their properties is considered. The article also discusses the modern safety assessment criteria contained in the preliminary regulatory documents of the manufacturing countries for new nanoliposome-based drugs being developed or used in the clinic.

Composite phospholipid-gold nanoparticles with targeted fragment for tumor imaging.

Gold nanoparticles and their conjugates have significant potential in the field of diagnosis of various diseases due to their SPR, which enhances light scattering and absorption. Conjugates of gold nanoparticles with various ligands can be used for imaging biomolecules or detecting malignant neoplasms at an early stage. This study focuses on the construction of composite (or hybrid) phospholipid-gold nanoparticles using soy phosphatidylcholine and a targeted ligand (folic acid derivative) to attach specific targeting properties. According to the method of dynamic light scattering, the diameter of the obtained nanoparticles was less than 100 nm, the results of the MTT test indicated their moderate cytotoxicity. In vitro and in vivo experiments showed a significant increase in the accumulation of phospholipid-gold nanoparticles with a targeted fragment compared to those without a targeted fragment both in HeLa cells and in a tumor (in BDF mice with an injected LLC tumor). The resulting nanoparticles are suitable for specific delivery into tumor cells and visualization of various malignant neoplasms, including at early stages, due to the increased expression of the folate receptor characteristic of cells of a wide range of tumors.

[Predict of metabolic stability of xenobiotics by the PASS and GUSAR programs]. / Prognoz metabolicheskoi stabil'nosti ksenobiotikov programmami PASS i GUSAR.

Metabolic stability refers to the susceptibility of compounds to the biotransformation; it is characterized by such pharmacokinetic parameters as half-life (T1/2) and clearance (CL). Generally, these parameters are estimated by in vitro assays, which are based on cells or subcellular fractions (mainly liver microsomal enzymes) and serve as models of the processes occurring in living organisms. Data obtained from the experiments are used to build QSAR (Quantitative Structure-Activity Relationship) models. More than 8000 compounds with known CL and/or T1/2 values obtained in vitro using human liver microsomes were selected from the freely available ChEMBL v.27 database. GUSAR (General Unrestricted Structure-Activity Relationships) and PASS (Prediction of Activity Spectra for Substances) softwares were used to make quantitative and classification models. The quality of the models was evaluated using 5-fold cross-validation. Compounds were subdivided into "stable" and "unstable" by means of the following threshold parameters: T1/2 = 30 minutes, CL = 20 ml/min/kg. The accuracy of the models ranged from 0.5 (calculated in 5-fold CV on the test set for the half-life prediction quantitative model) to 0.96 (calculated in 5-fold CV on the test set for the clearance prediction classification model).

[Targeted drug delivery system for doxorubicin based on a specific peptide and phospholipid nanoparticles]. / Sistema adresnoi dostavki dlia doksorubitsina na osnove spetsificheskogo peptida i fosfolipidnykh nanochastits.

Doxorubicin is one of the widely known and frequently used chemotherapy drugs for the treatment of various types of cancer, the use of which is difficult due to its high cardiotoxicity. Targeted drug delivery systems are being developed to reduce side effects. One of the promising components as vector molecules (ligands) are NGR-containing peptides that are affinity for the CD13 receptor, which is expressed on the surface of many tumor cells and tumor blood vessels. Previously, a method was developed for preparing a composition of doxorubicin embedded in phospholipid nanoparticles with a targeted fragment in the form of an ultrafine emulsion. The resulting composition was characterized by a small particle size (less than 40 nm) and a high degree of incorporation of doxorubicin (about 93%) into transport nanoparticles. When assessing the penetrating ability and the degree of binding to the surface of fibrosarcoma cells (HT-1080), it was shown that when the composition with the targeted fragment was added to the cells, the level of doxorubicin was almost 2 times higher than that of the liposomal form of doxorubicin, i.e. the drug in the system with the targeted peptide penetrated the cell better. At the same time, on the control line of breast adenocarcinoma cells (MCF-7), which do not express the CD13 receptor on the surface, there was not significant difference in the level of doxorubicin in the cells. The data obtained allow us to draw preliminary conclusions about the prospects of targeted delivery of doxorubicin to tumor cells when using a peptide conjugate containing an NGR motif and the further need for its comprehensive study.

Preclinical Study of Pharmacological Properties of Doxorubicin-NPh.

Preclinical study of therapeutic properties of an innovative drug Doxorubicin-NPh (doxorubicin in the form of ultrafine suspension of phospholipid liposomes) in comparison with free doxorubicin (Doxorubicin-Teva) and protected doxorubicin (Caelyx) was performed on transplanted murine tumor models. All these drugs were efficient in Ca755 breast carcinoma model (tumor growth inhibition ≈100%, increase in lifespan 90.6-114.3%). In P388 lymphocytic leukemia and LLC lung carcinoma, advantages of the protected doxorubicin by the benefit/risk ratio (width of therapeutic interval) were demonstrated: Caelyx>Doxorubicin-NPh>Doxorubicin-Teva. Doxorubicin-NPh and Caelyx exhibited similar therapeutic activity in the LLC model, especially when administered 3 times with 3-day intervals; for Doxorubicin-Teva, the optimal interval between the injections was 7 days.

[Chlorine e6 in phospholipid nanoparticles with specific targeting and penetrating peptides as prospective composition for photodynamic therapy of malignant neoplasms]. / Khlorin e6 v fosfolipidnykh nanochastitsakh so spetsificheskimi adresnymi i pronikaiushchimi peptidami kak perspektivnaia kompozitsiia dlia fotodinamicheskoi terapii zlokachestvennykh novoobrazovanii.

Cytotoxic and photoinduced activity of chlorine e6 (Ce6) in phospholipid nanoparticles with specific tumor targeting and cell-penetrating peptides was studied in vitro using human fibrosarcoma cells HT-1080. It was shown, that the binding of cell-penetrating peptide R7 - alone or combined with the peptide containing specific targeting motif NGR (Asn-Gly-Arg) - resulted in 3-fold decrease of Ce6 photoinduced activity as compared with that in nanoparticles without peptides (IC50 values were 0.7 µg/ml and 2.1 µg/ml, respectively). The NGR influence was unexpectedly low - less than 20% (IC50 1.7 µg/ml). This suggests the more importance of Ce6 cell penetration in this case, than of NGR-mediated targeting. The effect of inclusion of both peptides on the total cytotoxicity of Ce6 was minimal (10-16 times less than on the specific photoinduced activity). The obtained results - together with earlier shown effects on improvement of the pharmacokinetics of Ce6 in vivo after its embedding into phospholipid nanoparticles - indicate the prospects of using the obtained phospholipid nanoparticles system for photodynamic therapy.

[Prednisolone in phospholipid nanoparticles: prolonged circulation and increased antiinflammatory effect]. / Prednizolon v fosfolipidnykh nanochastitsakh: prolongirovannaia tsirkuliatsiia i povyshennoe protivovospalitel'noe deistvie.

Along with modern new drugs, many therapeutic schemes also include known effective drugs, particularly, glucocorticoids. One of the most distributed of them is prednisolone that has pronounced anti-inflammatory properties. Its disadvantage is short-term circulation, resulting in a number of side effects. For this reason the development of its more effective and safe formulations is carried out. We have obtained the formulation of prednisolone included in nanoparticles from soy phosphatidylcholine with an average diameter of 20 nm. With oral administration to rats and analysis by HPLC an increase in prednisolone maximal concentration in of plasma and the duration of circulation as compared with free drug administration were shown. The experiment with mice with conconavalin A induced inflammation was also carried out: conconavalin A was injected subplantary in an hour after oral administration of both prednisolone formulations in several doses. The index of the inflammatory reaction (determined by the edema degree) was suppressed more effectively in the case of prednisolone in nanoparticles. Maximal suppression (62.2% as compared with 49.6% for free prednisolone) was observed even at a minimal dose (2.5 mg/kg), at which the free drug did not act at all. The results indicate an increase in the efficiency of prednisolone included in phospholipid nanoparticles, that makes it possible to diminish its administered doses and thereby reduce the risk of side effects.

Effect of Cell-Penetrating Arginine Peptide on Interaction of Photosensitizer Chlorin e6 Incorporated into Phospholipid Nanoparticles with Tumor Cells.

We studied the possibility of increasing the efficiency of photodynamic therapy by improving delivery of photosensitizers chlorin e6 into tumor cells. Previous studies showed that incorporation of chlorin e6 onto phospholipid nanoparticles with a diameter <20 nm reduces its cytotoxicity due to accelerated elimination from organs [8]. A heptapeptide R7 synthesized and added to this combination promoted internalization of chlorin e6 into HepG2 cells in comparison with initial nanoparticles without peptide R7. The observed effect of peptide R7 can be explained by activation of endocytosis and/or macropinocytosis (bearing in mind the interaction of arginine with carboxyl groups of e6. The development of this transporting system is a promising trend in photodynamic therapy of cancer diseases.