Lipid Classification and Drug Delivery Systems

Lipid is the general term for fat and lipoid. It is a type of organic compound that is difficult to dissolve in water but easily soluble in organic solvents (such as ether, acetone, chloroform, etc.) and is used by the body. Lipids are mainly composed of three elements: carbon, hydrogen and oxygen. Some lipids also contain nitrogen, phosphorus and sulfur. Its chemical essence is esters and their derivatives formed by the condensation of fatty acids and alcohols. The fatty acids involved in lipid composition are mostly medium-chain or long-chain monocarboxylic acids with more than 4 carbon atoms, while alcohol components include glycerol (glycerol), sphingosine, higher monohydric alcohols and sterols.

Types of Fatty Acids

Usually fatty acid molecules are straight-chain fatty acids composed of 4-24 carbon atoms. The number of carbon atoms is usually an even number, except in rare cases. In addition to straight-chain fatty acids, there are cyclic fatty acids with cyclic structure, such as large maple oleic acid and sub-large maple oleic acid in maple oil for leprosy treatment, and cyclopropene fatty acids in cottonseed. Fatty acids are generally classified in two ways.

According to the number of carbon atoms:

• Short-chain fatty acids: Fatty acids with 4-6 carbon atoms.
• Medium chain fatty acids: Fatty acids with 8-12 carbon atoms.
• Long-chain fatty acids: Fatty acids with more than 12 carbon atoms.

According to the degree of saturation of fatty acid molecules:

• Saturated fatty acids (SFA): Fatty acids that do not contain carbon-carbon double bonds (C=C) in the fatty acid molecules.
• Monounsaturated fatty acids (MUFA): Fatty acids containing only one carbon-carbon double bond in the fatty acid molecule, such as oleic acid.
• Polyunsaturated fatty acids (PUFA): fatty acids with two or more double bonds, such as linoleic acid, linolenic acid, arachidonic acid, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). Usually, seafood contains polyunsaturated fatty acids with a wide range of physiological effects, such as fish oil, seaweed, etc. In order to indicate the position of the unsaturated bond in unsaturated fatty acids, ω or n is used internationally, that is, counting from the methyl end (or carbon end) carbon, the first unsaturated bond is at the 3, 6, and 9 carbon positions. Unsaturated fatty acids are classified into n-3, n-6, and n-9 series fatty acids.

Our Lipid Products

BOC Sciences is a trusted supplier of high-quality lipid products to researchers and pharmaceutical companies worldwide. With an ongoing focus on innovation, quality and customer satisfaction, we offer a broad range of lipid products to support lipid research, drug discovery and development efforts. A comprehensive range of lipid standards, including fatty acids, phospholipids, sphingolipids, sterols and lipid metabolites, are quickly available at BOC Sciences to meet the diverse needs of researchers in various fields.

Classification of Lipids

Can it be hydrolyzed by alkali:

• Saponifiable lipids (including fats and phospholipids) can be hydrolyzed by alkali to produce soaps (fatty acid salts).
• Non-saponifiable lipids, such as cholesterol and terpenoids, are the two main types of non-saponifiable lipids.

According to chemical composition:

Simple Lipids

Triglycerides, also called triacylglycerols, are composed of 3 molecules of fatty acids and 1 molecule of glycerol and are the most common form of fat in diets. Waxes are another class of simple lipids, consisting primarily of long-chain fatty acids and long-chain alcohols or sterols.

Complex Lipids

In addition to fatty acids and alcohols, lipids that contain other non-fat molecular components are called complex lipids. Mainly include: lipoproteins, glycolipids and phospholipids.

• Phospholipids, whose non-lipid components are phosphoric acid and nitrogenous bases (such as choline, ethanolamine), are divided into glycerol phospholipids (such as phosphatidic acid, phosphatidylcholine, phosphatidylethanolamine, etc.) and sphingosine phospholipids (referred to as sphingomyelin) due to different alcohol components.
• Glycolipids, whose non-lipid components are sugars (monosaccharides, disaccharides, etc.), and are divided into glycerolipids (such as monogalactosyl diacylglycerol, digalactosyl diacylglycerol, etc.) and glycosphingolipids (cerebrosides, gangliosides, etc.) due to different alcohol components.
• Lipoproteins, found in plasma, mitochondria, microsomes and cell membranes, are composed of lipids and proteins. The lipids in plasma lipoproteins include phospholipids, cholesterol, cholesteryl esters and triglycerides.

Derived Lipids

Substances derived from or closely related to simple lipids and complex lipids, but also have the general properties of lipids. It includes the following categories:

• Substituted hydrocarbons, mainly fatty acids and their saponifiers and higher alcohols, a small amount of aliphatic aldehydes, aliphatic amines and hydrocarbons.
• Steroids, including sterols, cholic acid, cardiac glycosides, sex hormones, adrenocortical hormones.
• Terpenoids, including many natural pigments (such as carotene), some essential oils, natural rubber, etc.
• Other lipids, such as fat-soluble vitamins (VA, VD3, VE, VK), acyl-CoA, eicosane-like (prostaglandins, thromboxane, leukotrienes), lipopolysaccharide and lipoprotein.

Polar and Non-polar Lipids

According to the different behavior of lipids in water and water interface, lipids can be divided into polar and non-polar lipids. Non-polar lipids have very low solubility in water (i.e., they do not have volumetric solubility) and cannot be dispersed into monolayers at the air-water interface or the oil-water interface (i.e., they do not have interfacial solubility). They mainly include long-chain aliphatic hydrocarbons (such as phytane, carotene, squalene), large aromatic hydrocarbons (such as cholesterol, sterane), esters formed by long-chain fatty acids and long-chain monohydric alcohols, long-chain fatty acid sterol esters, long-chain alcohol ethers, sterol ethers, glycerol long-chain triethers, etc. Polar lipids can be divided into the following categories:

Class I Polar Lipids

It has interface solubility, but does not have volume solubility. It can be incorporated into the cell membrane, but it cannot form a cell membrane (i.e. bimolecular layer). Including: triacylglycerol, diacylglycerol, long-chain undissociated fatty acids, long-chain n-alcohols and n-amines, phytol, retinol (one of the forms of VA), vitamin D, vitamin E, vitamin K, cholesterol, chain sterols (24-dehydrocholesterol), stigmasterol, undissociated phosphatidic acid, short-chain sterol ester, acid or alcohol partial carbon chain length less than 4 carbon atoms of wax (such as methyl oleate), ceramide, etc.

Class II Polar Lipids (Phospholipids and Glycosphingolipids)

Class II polar lipids can form cell membranes (phospholipid bilayers) and microvesicles, such as phosphatidylcholine, phosphatidylethanolamine, phosphatidylinositol, phosphatidylserine, cardiolipin, acetal phospholipid, sphingomyelin, cerebroside, ionized phosphatidic acid, monoacylglycerol, α-hydroxy fatty acid, glycerol monoether, sulfatide, and basic sphingosine.

Class III Polar Lipids (Detergents)

Soluble lipids have interfacial solubility, but the monolayer they form is unstable. This type of molecules can exist alone at low concentrations in water. When the concentration is higher than a certain concentration, they form small spherical aggregates, called micelles. This critical concentration is called the critical micelle concentration (CMC). Among these polar lipids:

• Class IIIA includes sodium and potassium salts of long-chain fatty acids, common anionic detergents, cationic detergents, non-ionic detergents, lysophosphatidylcholine, palmitoyl CoA, oleoyl CoA, ganglioside, acid sphingosine, etc.;
• Class IIIB includes conjugated bile salts, free bile salts, sulfated bile alcohols, sodium fumarate, saponins, rosin soap and penicillin.

Our Lipid Services

BOC Sciences is a leading provider of lipid synthesis and development services to researchers and pharmaceutical companies worldwide. With years of experience in lipid research and a team of expert scientists, we offer a wide range of services to support lipid-related research and drug discovery efforts. We have a state-of-the-art laboratory equipped with the latest technology and equipment for the synthesis of a wide range of lipids, including fatty acids, phospholipids, sphingolipids and sterols. BOC Sciences' experienced team of chemists can design and synthesize high-purity and high-quality custom lipids to meet the specific needs of each research project.

• Lipid cGMP Manufacturing
• Lipid Formulation Development
• Lipid Analysis and Characterization
• Lipid Synthesis Services
• Lipid Adjuvant Development
• Lipid Nanoparticles Development
• Lipid Extraction Services
• Fatty Acid Analysis Services
• Liposome Encapsulation Services
• Lipidomics Analysis Services
• Lipid Excipients Development

Lipid-based Drug Delivery Systems

The use of lipid products in drug development has revolutionized the field of drug delivery. As the demand for novel drug delivery systems continues to grow, lipid products are expected to play a key role in the development of new and improved drug formulations. Lipid-based drug delivery systems offer several advantages over traditional drug delivery systems:

• Lipids can increase the solubility of hydrophobic drugs. Lipid-based drug delivery systems help dissolve these drugs in lipid matrices, thereby improving their bioavailability and therapeutic efficacy.
• Lipid products protect drugs from degradation in the gastrointestinal tract. Lipid drug delivery systems protect drugs from the harsh acidic environment of the stomach and enzymatic degradation in the intestine.
• Lipids can facilitate targeted delivery of drugs to specific tissues or cells. For example, liposomes are lipid-based vesicles that can encapsulate drugs and utilize the enhanced permeability and retention (EPR) effect to deliver drugs to specific tissues or cells.
• Lipid-based drug delivery systems can provide sustained release of drugs, thereby prolonging therapeutic effects and reducing dosing frequency.
• Lipid products are also used to formulate lipid-based micelles, which are nanometer-sized structures formed by the self-assembly of lipids in aqueous solutions. Lipid micelles can dissolve hydrophobic drugs and improve their bioavailability by enhancing their absorption and distribution in the body.
• Nanoemulsions are another lipid-based drug delivery system that have received considerable attention in drug development. Nanoemulsions are colloidal dispersions of oil and water stabilized by surfactants that can encapsulate drugs and increase their solubility and bioavailability.

If you are interested in our lipid products or lipid services, please contact us for more information.