Pharmaceutics, Al Shifa College of Pharmacy, Kizhattur, Poonthavanam post, Perinthalmanna, Malappuram, Kerala-679325.
The term phyto refers to a plant, while'some' refers to cells. Phytosome is a new technique that is being applied to phytopharmaceuticals and consists of phytoconstituents and herbal extracts that are surrounded and bound by lipids. The absorption of phytosome is better than that of conventional herbal extracts, and leading to better bioavailability. Their pharmacological and pharmacokinetic properties have improved. The therapeutic effects of plant extracts and herbal lead molecules are enhanced by phytosomes, which increase bioavailability in the target site compared to conventional herbal extracts. The bioactive phytoconstituents of herb essence are enclosed and bound by a lipid in this improved herbal formulation..
The majority of the biologically active compounds in plants are polar or water soluble, but they are difficult to absorb because of the absorption problem. The use of these compounds is limited, which ultimately decreases their bioavailability1.To enhance bioavailability, herbal products must have a balanced balance between hydrophilic (for absorption) and hydrophobic (for absorption). Plant preparations have a wide range of uses. It is utilized in both traditional and modern medicine systems. Various pharmacological studies were carried out in traditional times. The therapeutic application of many plant extracts and their constituents have been tested in a Novel drug delivery such as targeted drug delivery2.
A number of chief constituents of herbal medicine are easily soluble in water (glycoside and flavonoid). However, these are not soluble in water. Constituents' potency is limited by their partial soluble or hydrophobic nature and when applied topically shows less therapeutic efficacy. Many attempts have been made to improve the bioavailability by forming drug delivery systems such as phytosomes and liposomes3.
Phytosomes refers to herbal drugs loaded in vesicles, which can be found in nano form. The phytosomes provide an envelope around the main ingredient of herbal extract and is similar to the coating around the active ingredient of a drug and they provide safety against degradation by digestive secretions and bacterias. A water-loving substance can be effectively absorbed by Phytosome and moves towards the lipid-loving environment of the cell membrane, and ultimately reaches the blood circulation4. Phosphatidylcholine, phosphatidylserine, phosphatidylethanolamine, and phosphatidylinositol are used as phospholipids, but phosphatidylcholine is widely used due to its therapeutic value in liver diseases, alcoholic steatosis, drug-induced liver damage, and hepatitis. Phospholipids are utilized to aid in digestion and transport both fat-soluble and water-soluble nutrients. The lipophilic path of the enterohepatic cell membranes and the stratum corneum layer of the skin is easily traversed by phytosomes5.
Phytosome Technology
Indena s.p.A of Italy created the Phytosome technology, which significantly improves the bioavailability of chosen phytomedicines by adding phospholipids to standardized plant extracts, which enhance their absorption and utilization. Polyphenols are little soluble both in water and in lipids. The interaction between the polar functionalities of the lipophilic guest and the charged phosphate head of phospholipids is unique and evidenced by spectroscopy. Phosphatidylcholine is a bifunctional molecule with both hydrophilic and hydrophobic phosphatidyl groups (Figure 1), and the head of the choline molecule binds to the compound, while the phosphatidyl portion encircles the bounded part.
The initial phytosome generation was created by blending selected polyphenolic extracts and phospholipids in nonpolar solvent. Nonetheless, recent phytosome generations have been crafted with the use of hydro-ethanolic solvent to comply current food specifications.
Phyto-Phospholipid Complex Components
According to Bombardelli's theory, active ingredients that are extracted from plants can react stoichiometrically with phospholipids to form phyto-phospholipid complexes. This preliminary description of phyto-phospholipid complexes has been questioned in light of later research. We have suggested an updated list of the four necessary elements based on the literature: phospholipids, solvents, phyto-active constituents, and the stoichiometric ratio involved in the formation of phyto-phospholipid complexes6.
Phospholipid
Plant seeds and egg yolk are rich in phospholipids. Phospholipids made in an industrial setting are currently accessible6. Depending on the backbone, phospholipids can be classified as glycerophospholipids or sphingomyelins. Phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidic acid (PA), phosphatidylinositol (PI), and phosphatidylglycerol (PG) are other glycerophospholipids.
The main phospholipids used to create complexes with a hydrophilic head group and two hydrophobic hydrocarbon chains are PC, PE, and PS . The most often utilized phospholipid among these is PC, which is used to create phospholipid complexes. The PC is organized as in figure1. PC has several advantages, one of which is its amphipathic qualities, which allow it to dissolve somewhat in lipid and water-based media. Furthermore, because PC is a crucial part of cell membranes, it has strong biocompatibility and minimal toxicity. PC molecules have been shown to have clinical benefits in the treatment of liver diseases, including hepatitis, fatty liver, and hepatocirrhosis. They also display hepatoprotective properties. High-affinity small molecule-phospholipid complexes of siramesine and PA were prepared by Patel et al.
Phyto-Active Constituents
Researchers typically define the active ingredients of herbal extracts based more on strong in vitro pharmacological effects than on in vivo activities. These substances are primarily polyphenols. The structural medications made of polyphenols are displayed below. Certain physiologically significant polyphenolic components found in plants, like hesperidin, have a preference for the aqueous phase and are unable to cross biological membranes. Some, like rutin and curcumin, on the other hand, have strong lipophilic characteristics and are insoluble in aqueous gastrointestinal fluids. In addition to increasing lipophilic polyphenol solubility in aqueous phase, phyto-phospholipid complexes also increase hydrophilic polyphenols' ability to pass through membranes from an aqueous phase. Additionally, the synthesis of complexes can shield polyphenols from degradation caused by outside factors like hydrolysis, photolysis and oxidation8.
Hesperidine Curcumin Rutine
Therapeutic Applications Of Different Phyto-Phospholipid Complexes On The Market
SOLVENTS
Researchers have used a variety of solvents as the reaction medium when creating phyto-phospholipid complexes. Protic solvents like ethanol have largely replaced the aprotic ones that were previously used to prepare phyto-phospholipid complexes, such as methylene chloride, ethyl acetate, aromatic hydrocarbons, halogen derivatives, cyclic ethers, etc. [23], [38]. In fact, phospholipid complexes have been successfully prepared in more recent times using protonic solvents like methanol and ethanol. For instance, Xiao used ethanol as a protonic solvent to create silybin-phospholipid complexes, which were then vacuum-sealed at 40°C to eliminate the protonic solvent.
Solvents of different kinds have been effectively studied. Ethanol is a popular and useful solvent that leaves less residue and causes minimal damage when the yield of phospholipid complexes is high enough. When water or a buffer solution is present, certain liposomal drug complexes function by allowing the phytosomes to interact with a solvent that has a lower dielectric constant9.
The supercritical fluid (SCF) process has been used in numerous studies recently to control the morphology, size, and shape of the material of interest. One of the SCF technologies that is starting to show promise for producing micronic and submicronic particles with regulated sizes and size distributions is the supercritical anti solvent process (SAS) [39]. To lessen the solute's solubility in the solvent, this technique uses a supercritical fluid—typically CO2—as an anti-solvent.
Phytosome Advantages
1.Because of their complexation with phospholipid and improved absorption in the intestinal tract, botanical extracts have a remarkable increase in bioavailability.
2. They penetrate the non-lipophilic botanical extract, making it possible for improved absorption from the intestinal lumen, which would not be possible otherwise.
3. Phytosome's composition is safe, and each of its ingredients has been given the go-ahead for usage in cosmetic and pharmaceutical applications.
4. They have been used to deliver flavonoids that protect the liver because phytosomes can make them readily bioavailable. Furthermore, phosphatidylcholine has hepatoprotective properties as well, which work in concert to protect the liver. Using this technology as functional cosmetics to shield the skin from external or internal dangers provides an economical way to deliver phytoconstituents and synergistic benefits.
5. When used as functional cosmetics to shield the skin from external or internal dangers, this technology provides an affordable way to deliver phytoconstituents and synergistic benefits.
6. They can also be utilized to improve drug penetration through the skin for dermal and transdermal administration.
7. These serve as a delivery system for a wide range of medications (peptides, protein molecules).
8. There is an instant commercialization option for the non-invasive, passive vesicular system.
9. Phosphatidylcholine serves as a carrier and skin nourishment. It is a crucial component of the cell membrane utilized in phytosome technology.
10. Drug entrapment does not present a problem when the formulation is being prepared. Furthermore, the entrapment efficiency is high and predetermined due to the drug's formation of vesicles following conjugation with lipid.
PROPERTIES OF PHYTOSOMES
(I) Physico Chemical Properties
As previously mentioned, a standardized plant extract is used as the substrate in a reaction with a stoichiometric amount of phospholipid to create phytosomes. According to the spectroscopic data, the phospholipid-substratum contact results from the polar head (phosphate and ammonium group) and the polar functions of the substrate forming a hydrogen bond. A phytosome can range in size from 50 nm to a few 100 µm. When phytosomes are exposed to water, they take on a micellar form that is similar to a liposome. Photon Correlation Spectroscopy (PCS) can be used to see these liposomal structures that the phytosomes have gained. The 1HNMR and 13CNMR findings suggest that the fatty chain provides unaltered signals in both the complex and free phospholipid. This suggests that lengthy aliphatic chains are coiled around the active principle to form a lipophilic envelope. In terms of phytosome solubility, the complexes are frequently insoluble in water, somewhat unstable in alcohol, readily soluble in aprotic solvents, and moderately soluble in lipids. However, after complexing with phospholipids, the phytosomes of some lipophilic phytoconstituents, such as curcumin, have demonstrated enhanced water solubility, which has been studied.
(II) Biological Properties
Phytosomes are novel complexes which are better absorbed and utilized; hence they produce more bioavailability and better result than the conventional herbal extract or non-complexed extracts, which has been demonstrated by pharmacokinetic studies or by pharmacodynamic tests in experimental animals and in human subjects. Because of their physical size, membrane permeability, percentage of entrapment, chemical makeup, quantity, and purity of the ingredients used, phytosomes can exhibit their behavior in physical or biological systems.
Phytosomes are not to be confused with liposomes, which are encapsulated hydrophilic drug molecules in gaps or cavities between membranes.
These days, liposomes are primarily employed for cosmetic purposes and can entrap several hundred phospholipid molecules. Rather, the phytosomes entail the interplay between one to four phospholipid molecules and the chemically linked phytoconstituents. Numerous studies have demonstrated that in terms of membrane permeability and durability, phytosomes are a superior substitute for liposomes.
Comparison Between Phytosome And Liposome
Numerous studies have been conducted on phytosomes, and the results indicate that they are more therapeutically effective than liposomes and have good bioavailability and absorption. Table 1 compares phytosomes with liposomes, while Figure shows their structural arrangement.
Preparation Of Phytosome
Typically, to make phytosomes, a precise amount of phospholipid—soy lecithin—is added along with plant extracts in an aprotic solvent. The primary component of soy lecithin is phosphatidylcholine, which serves two purposes.
The phosphoryl portion has a lipophilic character, while the choline portion has a hydrophilic one. While the phosphatidyl component is a lipid soluble substance associated to the choline bound complex, the choline part is attached to the primary active ingredients that are hydrophilic. It causes a lipid complex to develop that is more stable and bioavailable.
Alternatively, a synthetic or natural phospholipid can be reacted in a ratio of 0.5-2.0 with the standardized plant extract to create phytosomes. However, a 1:1 ratio is generally preferred. The reaction can be conducted in an aprotic solvent, such as acetone, methylene chloride, or dioxane, alone or in a natural mixture. The novel complex can then be isolated by lyophilization, spay drying, precipitation with a non-solvent (typically an aliphatic hydrocarbon), or by any combination of these methods.
Sometimes the solubilization or complex formation is accomplished by refluxing the mixture of the stoichiometric ratio in the aprotic solvent for a predetermined amount of time.
Using a thin layer rotary evaporator vacuum method, phytosome vesicles were created. Anhydrous ethanol was used to combine the phytosomal complex in a 250 ml round-bottom flask. A rotary evaporator had the flask attached to it.At roughly 60°C, the solvent will evaporate and form a thin layer film around the flask. Phosphate buffer, with a pH of 7.4, hydrates the film. The lipid layer peels off in the phosphate buffer, creating a suspension of vesicles. The phytosomal suspension was sonicated with a 60% amplitude probe. Before being characterized, the phytosomal suspension will be kept in the refrigerator for a full day. The reflux method is one way to prepare phytosomes. After adding phospholipid and polyphenolic extract to a 100 mL round-bottom flask, it was refluxed in DCM for one hour at a temperature not to exceed 40°C. After evaporating the clear solution, 15 mL of n-hexane was added until a precipitate formed. After being removed, the precipitate was put in a desiccator.
Phospholipid and cholesterol should be precisely weighed into a round-bottom flask, dissolved in 10 mL of chloroform, and then sonicated for 10 minutes with a bath sonicator. It is possible to remove organic solvent by putting it in a rotating evaporator at 40°C with reduced pressure. In a rotary evaporator, a thin layer that has been completely stripped of the solvent and hydrated with the drug's polyphenolic extract is created. To dissipate heat, the phospholipid mixture was Sonicated in an ice bath. The prepared phytosomes were kept in a bottle with an amber tint. The procedure's diagrammatic representation is displayed in Figure,
Mechanism Of Phytosome Technology
There are two main reasons for the reduced absorption and bioavailability of polyphenolic constituents. These main components are several ringed molecules that aren't too tiny to be absorbed through the diffusion process. The second factor is the low solubility of flavonoid molecules, or the main components of polyphenols, with lipids. These are the restrictions preventing them from being absorbed through biological membranes. The primary process of phytosome technology is the complexation of polyphenols with phospholipid in a 1:1 or 1:2 ratio, which forms a phytosomal complex with a lipid layer encircling the constituents.
CHARACTERISATION OF PHYTOSOME
Partition Coefficient And Solubility
To characterize active constituents, phyto-phospholipid complexes with active constituents, and physical mixtures, it is necessary to ascertain solubility in either water or organic solvents, as well as the n-octanol/water partition coefficient (P). Phyto-phospholipid complexes are generally more hydrophilic and lipophilic than active ingredients, with lipophilicity being particularly enhanced. It is verified that compared to embelin and its corresponding physical mixtures, embelin in complex is more soluble in n-octanol and water.
Zeta Potential And Particle Size
Important complex properties that are connected to stability and repeatability are particle size and zeta potential. Phospholipid complexes typically had particle sizes ranging from 50 nm to 100 µm. Mazumder synthesized sinigrin phytosome complexes, with an average particle size of 153 ± 39 nm and a zeta potential of 10.09 ± 0.98 mV, respectively.
Differential Scanning Calorimetry
The drug phospholipid complex, phosphatidylcholine, polyphenolic extract, and a physical mixture of the drug and phosphatidylcholine were all placed in an aluminum cell and heated to a temperature of 50–250°C/minute from 0 to 400°C in a nitrogen atmosphere.
Scanning Electron Microscopy (Sem)
The particle's appearance and size were assessed using SEM. A dry sample was put on an ion sputter-coated brass stub for an electron microscope. scanning the complex at random speed of 100.
Transition Electron Microscopy (Tem)
TEM was used to characterize the size of phytosomal vesicles with 1000 magnification
Drug Entrapment And Loading Capacity
Separating the phytosome from the unentrapped drug required 90 minutes at 4°C and 10,000 rpm centrifugation of the drug phytosome complex. UV spectroscopy can be used to measure the amount of free drug present. The following formula can be used to determine the percentage of drug entrapment:
Weight of total drug – Entrapment efficiency % = ????????????????????? ???????? ???????????????? ???????????????? ????????????????? ???????? ???????????????????? ???????????????? × 100
Fourier Transform Infrared Spectroscopy (Ftir) Analysis
FTIR analysis is performed to verify the phospholipid drug's chemical stability and structure. Using potassium bromide, the phytosomal medication will be crushed to create pellets under 600 kg/cm2 pressure. The ranges that will be scanned are 4000-400 cm?1.
Size Analysis And Zeta Potential
The Malvern Zetasizer is used to measure the phytosomal complex's particle and zeta sizes. For this particle size and zeta sizer characterization, an argon laser is employed.
In Vitro And In Vivo Evaluations
The drug's qualities, its primary phytoconstituents surrounded by a phospholipid layer, and the reason that specific animal model is chosen for its evaluation all play a role in the in vitro and in vivo evaluations.
Applications
Throughout the last hundred years, the fields of phytochemical and phytopharmacological sciences have determined the chemical compositions, biological properties, and health-promoting advantages of various plant-based products. Molecules that are polar or water soluble make up the majority of the biologically active components of plants. However, water soluble phytoconstituents (such as tannins, terpenoids, flavonoids, etc.) are poorly absorbed because of their large molecular size, which prevents passive diffusion from absorbing them, or because of their poor lipid solubility, which severely restricts their ability to cross biological membranes rich in lipids, leading to poor bioavailability.
The natural component synergy is lost during the separation and purification of an extract's constituents, which has frequently been observed to result in a partial or complete loss of the purified constituent's specific bioactivity. The chemical complexity of the unrefined or partially refined extract is frequently thought to be crucial for the active ingredients' bioavailability. Certain components of extracts may be destroyed in the stomach environment when consumed orally. Because of the aforementioned factors, low bioavailability frequently restricts the therapeutic usefulness of established standardized extracts.
It has been noted that complexing these extracts and their individual components with a few other clinically beneficial nutrients significantly increases their bioavailability. Phospholipids are among the nutrients that are particularly useful for improving absorption. Using patented technology, a top pharmaceutical and nutraceutical manufacturer created phytosomes, which are lipid-soluble molecular complexes that greatly increase phospholipids' absorption and bioavailability. Phytosomes are created by incorporating standardized plant extracts or water-soluble phytoconstituents into phospholipids.
The water-soluble material in liposomes is surrounded by phosphatidylcholine molecules, which do not form a chemical bond. The water-soluble compound may be surrounded by hundreds or even thousands of phosphatidylcholine molecules. 2:1 molecular complex depending on the substance(s) complexed, involving chemical bonds. Phosphodiethylcholine and the plant components, on the other hand, actually form a 1:1 or a 2:1 molecular complex with the phytosome process, depending on the substance(s) complexed, involving chemical bonds. All known life forms use phospho-lipids, which are complex molecules, to form their cell membranes.
Phospholipids are also used by humans and other higher animals as natural digestive aids and as carriers of nutrients that are both water- and fat-soluble. They are readily absorbed when taken orally and are miscible in lipid and water environments. Because phytosomes have a greater ability to pass through the lipoidal biomembrane and eventually enter the systemic circulation, they are more bioavailable than traditional herbal extracts.
REFERENCE
Fathima Shana A.*, Afnan K. V., Afra, Phytosomes As Novel Drug Delivery System, Int. J. of Pharm. Sci., 2024, Vol 2, Issue 8, 2446-2454. https://doi.org/10.5281/zenodo.13172377
10.5281/zenodo.13172377
