Other Lipid

Fatty acids (FA), glycerides, phospholipids, sterols, sphingolipids, and prenol lipids are examples of hydrophobic macromolecules known as lipids. As structural elements, hormones, and signaling molecules, lipids are crucial to energy metabolism and storage. Numerous illnesses, including cancer, diabetes, viral diseases, neurological diseases, and inflammatory diseases, disrupt the enzymes and pathways involved in lipid metabolism. In addition, lipids and lipid excipients also affect how well drugs are absorbed and delivered.

BOC Sciences is a leading supplier of lipids and lipid derivatives, offering a broad range of high-quality products to meet the diverse needs of researchers and industry worldwide. Our lipid derivative supply capabilities cover natural lipids such as fatty acids, phospholipids and sterols, as well as synthetic lipid derivatives such as sphingolipids, glycolipids and liposomes. These products are available in a variety of purities and quantities to meet diverse research needs, from basic research to drug discovery and development. In addition to off-the-shelf products, BOC Sciences offers a high level of custom synthesis of lipids and flexibility in lipid analysis capabilities.

Lipid Derivatives for Research

The application of lipidomics can help us study lipid metabolism and help us understand the underlying mechanisms of various metabolic diseases and the role of lipids in regulating homeostasis. The identification of specific lipid biomarkers and mechanism-based knowledge of specific metabolic lipid processing pathways associated with different pathologies is fundamental for the development of innovative therapeutic approaches to treat different pathologies. In addition, lipid carriers can also be widely used in drug delivery, especially the use of lipid prodrugs. Lipid prodrugs contain a drug covalently linked to a lipid carrier (eg, FA, glycerides, phospholipids, or steroids). This combination results in higher lipophilicity compared to the individual drugs, thus leading to better pharmacokinetic profiles and providing other significant benefits such as improved absorption through biological barriers, prolonged blood half-life, selective distribution to tissues (e.g., brain, intestine), reducing hepatic first-pass metabolism and generally improving drug bioavailability. Drug-lipid conjugates can also join physiological lipid transport pathways and enable drug targeting to specific sites.

Lipids in Drug Discovery

Lipids have great potential in disease treatment, from being disease markers that enable drug targeting, to being used as supplements themselves, and as part of lipid pharmaceutical formulations and as carriers for specific drugs. Some lipid prodrugs (mainly FA-drug conjugates) proved very successful in preclinical studies and were therefore accepted into clinical studies. As mentioned earlier, some unsaturated fatty acid (UFA) derivatives combined with chemotherapy drugs have entered clinical trials, the most important of which are gemcitabine-elaidic acid, cytarabine-elaidic acid, paclitaxel-docosahexaenoic acid, and lipophilic docetaxel. Prodrug (MNK-010). Additionally, a cholesterol-siRNA prodrug (ARC-520) entered clinical trials for the treatment of chronic hepatitis B infection. Anticipated directions for the development of novel lipid prodrugs containing glyceride/PL carriers may include greater improvements in prodrug design in which linkers/spacers will allow controlled release of the parent drug from the prodrug complex.

Fig. 1. Examples of chemical structures of the major lipid classes (Int J Mol Sci. 2020, 21(9): 3248).

Fatty Acids (FA)

FA contains hydrocarbon chains of varying lengths and degrees of desaturation. Many lipids are synthesized from FA; for example, phospholipids and glycerides contain hydrophobic FA tails, as well as triacylglycerides, which are synthesized and stored in a state of increased nutrient availability. Under physiological conditions, de novo FA synthesis in humans originates from the liver, breast during lactation, and adipose tissue. However, in pathological conditions such as cancer, FA biosynthesis has been shown to play an important role. For example, UFAs have been found to possess some endogenous anticancer properties, as well as some ability to promote the chemotherapeutic effects of anticancer drugs. UFAs have good biocompatibility, natural tumor targeting properties, and possible pharmacological activity in cancer treatment; therefore, they provide good lipid carriers for the development of prodrugs in cancer treatment. The conjugation of UFA to chemotherapy drugs has been shown to increase the lipophilicity of the drug, which may enable cells to take up anticancer drugs through passive transport (this is particularly important for water-soluble nucleoside drugs). Anticancer agent-UFA conjugates entering clinical trials include gemcitabine-elaidic acid (CP-4126), cytarabine-elaidic acid (CP-4055), and paclitaxel-DHA (PTXDHA) prodrugs.

Glycerides

Triglycerides (TG) can be used to enhance the formulation of highly lipophilic drugs. They can be various combinations of TG oil, TG, DG and MG. The type of oil used in a formula has a significant impact on the formula's ability to improve absorption. Non-digestible lipids, such as sucrose polyesters, are not absorbed by the intestinal membrane, whereas digestible lipids, such as DG, TG, PL, FA, cholesterol and some synthetic derivatives, are suitable components of pharmaceutical preparations. According to the degree of saturation, interaction with water and the length of the carbon chain, it can be divided into long chain TG (LCT), medium chain TG (MCT), DG, MG, FA, PL, etc. Glycerides have an important role in the development of novel prodrugs with improved targeting properties compared to the parent drug. Typically, TG-drug conjugates undergo lymphatic transport and lymphatic drug delivery.

Phospholipids

The therapeutic effect of phospholipids on a variety of diseases has been demonstrated, for example, certain phospholipid fractions have therapeutic activity against ulcerative colitis. Some clinical trials have shown that adding phosphatidylcholine (PC) to the colonic mucosa can reduce inflammatory activity.  In addition, dietary lecithin (a mixture of phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine, and phosphatidic acid) has been shown to have a protective effect on cholestatic liver disease in cholic acid-fed Abcb4-deficient mice and can significantly reduce liver damage. Oxidized phospholipids are present in inflamed tissues and are thought to have an important role in the regulation of immune responses. In most studies, oxidized phospholipids have pro-inflammatory properties, but research has shown that specific phospholipid oxidation products can exhibit anti-inflammatory properties. In fact, derivatives of oxidized phospholipids may be new therapeutic options for immune diseases, namely atherosclerosis, psoriasis, multiple sclerosis, and rheumatoid arthritis.

Steroids

Cholesterol is the main sterol synthesized by the human body. It can be derived from the diet or synthesized de novo in the body. As mentioned earlier, it has a variety of roles, ranging from being a structural component of cell membranes, part of different classes of phospholipids, to being a precursor of steroid hormones, bile acids, and vitamin D. In addition to these physiological roles, cholesterol also plays an important role in the pathogenesis of certain cancer types. Studies have found that low cholesterol serum levels are associated with lung, cervical, breast, colon and leukemia, while high cholesterol levels are associated with brain tumors. For example, prostate cancer is considered a lipid-rich tumor, and the androgen receptor plays a major role in the development of this cancer. Additionally, cholesterol is a precursor to estrogen, and elevated estrogen levels are associated with increased risk of breast cancer. In growing cancer cells, cholesterol is required to build cell membranes, which are synthesized more rapidly in these tissues; cholesterol is obtained de novo or through low-density lipoprotein particles via high-affinity receptor-mediated uptake. In many cases, cancer cells exhibit a high affinity for low-density lipoprotein (LDL) particles compared to normal cells. The increased demand for LDL by malignant cells and the overexpression of LDL receptors could be used to develop novel targeted drug delivery systems, including cholesterol-based prodrugs.

Reference

1. Markovic, M. et al. Lipids and Lipid-Processing Pathways in Drug Delivery and Therapeutics. Int J Mol Sci. 2020, 21(9): 3248.