About Author:
Ramandeep Kaur
Assistant Professor, CT Institute of Pharmaceutical Sciences,
Jallandhar- 143001

Phytosomes are little cell like structure which are also termed herbosomes which are formed by complexation of the polyphenolic phytoconstituents in molar ratio with phosphatidylcholine. Bioavailability of flavonoid containing phytomedicines, is reported to be low and erratic due to limited absorption, elevated presystemic metabolism and rapid elimination. But their phytosomal formulations show improved absorption, enhanced delivery and increased bioavailability of phytochemicals than the conventional herbal extracts containing dosage forms. Phytosome technology has been effectively used to enhance the bioavailability of many popular herbal extracts e.g. milk thistle, grape seed, green tea, hawthorn, etc. The improved pharmacokinetic and pharmacological properties of phytosomes make them suitable for the treatment of serious degenerative disorders. This article reviews the recent trends and applications of various herbal extract phytosomes as a tool of drug delivery system and as an emerging technology for increasing bioavailabity of phytoconstituents.

Reference Id: PHARMATUTOR-ART-1399

Herbal medicine is employed by mankind from the ancient times and during the last century chemical and pharmacological studies have been performed on a lot of plant extracts in order to know their chemical composition and to confirm their indications for treating diseases. There is a great interest and medical need for the improvement of bioavailability of a large number of herbal drugs and plant extracts which are poorly lipid soluble and so less bioavailable1. In human body, the phospholipids are also used as natural carriers for both fat-miscible and water miscible nutrients. Most of the plant constituents specifically phenolics are water soluble and the reason for less bioavailability is the inability to cross the lipid membranes of intestine. Their bioavailability can be improved with the use of different novel delivery systems like liposomes, marinosomes, niosomes and photosomes which can enhance the rate of release as well as the capacity to cross the lipid rich biomembranes2, 3. Recent technology - phytosome process, a breakthrough in herbal medicine, is being used to refine, enhance, and intensify the power of herbal medicines. Phytosome dietary supplements are the modern culmination of this great tradition. Phytosome is a patented technology developed by a leading manufacturer of drugs and nutraceuticals (Indena), which are prepared by incorporating standardized plant extracts or water soluble phytoconsituents into phospholipids to produce lipid compatible molecular complexes, in order to vastly improve their absorption and bioavailability4-7.

Phospholipids are small lipid molecules where glycerol is bonded to two fatty acids, while the third hydroxyl, normally one of the two primary methylenes, bears a phosphate group bound to a biogenic amino or to an amino acid. Phospholipids are a class of lipids and are a major component of all cell membrane. They are miscible both in water and in lipid environments, and are well absorbed orally. Phospholipids from soybean, (Glycine max) mainly phosphatidylcholine is a lipophilic agent that readily complex polyphenolics and widely employed to make phytosomes8.

Phosphatidylcholine, the major molecular building block of cell membranes is a compound miscible in both water and in oil/lipid environments9. The phytosomes has more ability to carry the herbal extract of hydrophilic nature through the lipid bilayer and thus its bioavailablity is more compared to simple extract. The phytosome technology has been reported to effectively enhance the bioavailability of many popular herbal extracts including milk thistle, Ginkgo biloba, grape seed, green tea, hawthorn, ginseng, turmeric, centella, ammi etc and can further be developed for various therapeutic uses or dietary supplements10, 11. The Phytosomes process itself produces a little cell whereby the valuable component of the herbal extract is protected from degradation by digestive secretions and gut bacteria12.

Common Drug Delivery Systems used in Pharmaceutical technology:
The “Somes” the cell like formulations of novel drug delivery system. There are different types of somes like
Liposomes are nano size artificial vesicles of spherical shape that can be
produced from natural phospholipids and cholesterol.

Herbosomes are purified phytochemical extracts complexed with phospholipids for a better bioavailability and enhanced biological activities.

Cubosomes are nanoparticles but instead of the solid particles, cubosomes are self-assembled liquid crystalline particles of certain surfactant with proper ratio of water with a microstructure that provides unique properties of practical interest.

Colloidosomes are solid microcapsules formed by the self assembly of colloidal particles at the interface of emulsion droplets which are hollow, elastic shells whose permeability and elasticity can be precisely controlled.

Ethosomes are noninvasive delivery carriers that enable drugs to reach the deep skin layers and/or the systemic circulation. They contain phospholipids, alcohol (ethanol and isopropyl alcohol) in relatively high concentration and water.

Aquasomes these are spherical 60300nm particles used for drug and antigen delivery. The particle core is composed of noncrystalline calcium phosphate or ceramic diamond, and is covered by a polyhydroxyl oligomeric film. Aquasomes were prepared by self-assembling of hydroxyapatite by co-precipitation method and thereafter preliminary coated with polyhydroxyl oligomers (cellobiose and trehalose) and subsequently adsorbed with bovine serum albumin (BSA) as a model antigen. BSA-immobilized aquasomes were around 200 nm in diameter and spherical in shape and had approximately 20-30% BSA-loading efficiency.

Pharmacosomes are pure drug vesicles formed by the amphiphilic drugs. Any drug possessing a free carboxyl group or an active hydrogen atom (–OH, NH2) can be esterified (with or without a spacer group) to the hydroxyl group of a lipid molecule, thus generating an amphiphilic prodrug. The amphiphilic prodrug is converted to pharmacosomes on dilution with water.

Niosomes are non-ionic surfactant vesicles and, as liposomes,are bilayered structures. Niosomes present low production cost, greater stability, andresultant ease of storage.Niosomes are chemically stable, can entrap both lipophilic and hydrophilic drugs either inaqueous layer or in vesicular membrane and present lowtoxicity because of their non-ionic nature.

Proniosomes are dry formulations of surfactant-coated carrier, which can be measured out as needed and rehydrated by brief agitation in hot water.



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