INTRODUCTION:

During the last century physicochemical, analytical and pharmacological studies have been performed on a numerous number of plant extracts in order to know their chemical composition and therapeutic effect to confirm as traditional medicine. Herbal medicines or active phytoconstituents extracted or isolated from different parts of plant have been widely used all over the world to treat various diseases, since ancient times and have been recognized by physicians and patients for their pharmacological or biological value as they have no or fewer side effects as compared with synthetic drug. Various plant materials have been observed to exhibit a variety of biological activity such as antilipidemic activity, hepatoprotective activity, immunomodulatory activity etc. Development of novel drug delivery systems (NDDS) is a new approach for plant extracts and active components⁽¹⁾. Novel Drug delivery systems (NDDS) are capable of designing to increase the bioavailability of drugs, control drug delivery and maintain the drug intact transport to the site of action while avoiding the non-diseased host tissues ^(2).

However, many active constituents containing polyphenolic group,extracted from plants are poorly absorbed when administered orally, which limits their widespread application ^(2,3). Some of the basic reasons for the poor bioavailability of these substances are low aqueous or lipid solubility, high molecular weight/size and poor plasma membrane permeability^{(4,5, 6)}. Moreover the standardized extracts when administered orally lose some of their constituents in the presence of gastric fluids ^(7). This has restricted the use of pharmacologically effective polyphenolic plant actives for treating different disorders. Active constituents extracted from natural plants have shown to exhibit robust in vitro pharmacological effects, but poor in vivo absorption ^(8). The bioavailability of active principles of plants have become an issue of concern for researchers and formulation scientist. Therefore numerous methods like development of herbal formulation in the form of liquid solution or dispersion system have been proposed to counter the problem of poor absorption ⁽⁹⁾ , such as the preparation of emulsions⁽¹⁰⁾ , liposomes ⁽¹¹⁾ , and nanoparticles⁽¹²⁾, as well as the modification of chemical structures⁽¹³⁾ and delivery as prodrugs ⁽¹⁴⁾. Among the potential strategies, phytophospholipid complexes (known as phytosomes) have emerged as a promising strategy to enhance the bioavailability of active constituents⁽¹⁵⁾. In recent years, the technique of complexing plant drugs with phospholipids have emerged as a challenging and one of the most successful methods for improving bioavailability and therapeutic efficacy of a number of poorly absorbed plant constituents. Phyto phospholipid complexes are prepared by complexing active constituents at defined molar ratios with phospholipids under certain conditions.

After forming phospholipid complexes, the biological membrane permeability and oil–water partition coefficient of constituents are greatly improved. Thus, phytophospholipid complexes are more readily absorbed and generate higher bioavailability compared to free active constituents ^(16,
17). Encouragingly, the techniques of phospholipid complexes have overcome the obstacle of poor bioavailability for many active constituents^(18,
19).Therefore, the preparation of phytophospholipid complexes have recently received increased attention.

PHYTOPHOSPHOLIPID COMPLEX:

However, a lot of strategies or approaches are used to improve the therapeutic efficacy and bioavailability of herbal /plant extract. Among these, the complexation technique in which, the complexation of naturally occurring plant extract or phytoactive molecule with phospholipid molecules has attracted the researcher to develop a novel carrier system for improving the bioavailability of poorly absorbed plant extracts/actives. This is because of unique molecular structure of phospholipid components, which are similar to the lipid component of the mammalian cell membrane that makes them highly biocompatible with the human physiological system.⁽²⁰⁾The drug phospholipids complexation technique was first developed in the year 1989 in Italy, by chemically reacting polyphenolic extracts with phospholipids containing phosphatidylcholine. The mixture markedly increased the bioavailability of the polyphenolics when compared with the bioavailability of pure extract ^(21).

COMPONENTS OF PHYTOPHOSPHOLIPID COMPLEX:

From the research Bombardelli proposed that the complexation of phytocompound with phospholipids is due to the reaction of phospholipids at a stoichiometric ratio with active phytoconstituents that are extracted from plants⁽²²⁾. As per the literature survey, the researcher proposed that there are four essential components needed for phytophospholipid complexation, phospholipids, phytoactive constituents, nature of solvents, and the stoichiometric or molar ratio⁽²³⁾.

PHOSPHOLIPIDS:

Phospholipids are lipids that contain phosphorus, a polar head portion and non polar tail portion in their structure ⁽²³⁾. Phospholipids are abundant in egg yolk and plant seeds. Phospholipids can be divided into glycerol phospholipids and sphingomyelins depending on alcohol contained in phospholipid backbone.

Glycerophospholipids: Glycerophospholipids which are the main phospholipids in eukaryotic cells, refer to the phospholipids in which glycerol is the backbone. All naturally occurring glycerophospholipids possess a-structure and L-configuration⁽²⁴⁾Additionally, glycerophospholipids include phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidic acid (PA), phosphatidylinositol (PI), and phosphatidyl- glycerol (PG ⁽²³⁾. PC, PE, and PS are the major phospholipids used to prepare phytocomplexes, that are composed of a hydrophilic head group and two hydrophobic hydrocarbon chains ⁽²⁵⁾.

Variation in the head group present in the phospholipid leads to the development different glycerophospholipids, such as phosphatidylcholine (PC), phosphatidylethanolamine (PE), phosphatidylserine (PS), phosphatidic acid (PA), phosphatidylinositol (PI), phosphatidylglycerol (PG) cardiolipin (CL) .The length of the polar moieties leads to different glycerophospholipids, e.g. dipalmitoyl, dimyristoyl, distearoyl PC⁽²³⁾. phosphatidylcholine (PC) are amphipathic in nature so it gives the moderate solubility in polar and non polar media. From the research it has been proved that PC showed the hepatoprotective activities, and have been reported to show clinical effects in the treatment of liver diseases, such as hepatitis, fatty liver, and cirrhosis ^(26).

Sphingomyelins (SM):^(23,27,28)SMs are an important component of animal cell membranes. Although PC and SM are very similar in molecular structure, they still have some differences.

1) Sphingosine is present in SM backbone, while glycerol is in the backbone of PC.

2) Each SM molecule averagely contains 0.1 - 0.35 cis-double bonds in amide-linked acyl chains and PC contain 1.1- 1.5 cis-double bonds. It can be concluded that the saturation of hydrophobic regions of SMs is higher than that of PCs.

3) The naturally SMs, contain typical acyl length are usually more than 20 while the paraffin residues of sphingosine are relatively shorter, so the SMs are asymmetric molecules and PCs typically contain moderate lengths (16-18) of the acyl chains and length of two chains are approximately equal so the PCs are symmetric molecules .

4) SMs are capable of forming intermolecular and intramolecular hydrogen bonds, so the SM and PC bilayer have a significant difference in the macroscopic properties.

5) The range of phase transition temperature (Tc) of all naturally occurring SMs is 30-45 ⁰C which is above the natural PCs.

PHYSICOCHEMICAL PROPERTIES OF PHOSPHOLIPIDS: Phospholipids are amphipathic molecules having considerable solubility in aqueous and oily mediums. They have a polar and a nonpolar portion in their structures ⁽²⁹⁾. The phospholipids are one of the major components of the mammalian cell membrane. In the eukaryotic cell membrane glycerol based lipids are predominantly present which includes phosphatidylcholine, phosphatidylinositol, phosphatidylethanolamine, phosphatidylserine and cardiolipin. Phosphatidylcholine possesses a cylindrical shape with highest entropy and is involved in formation of bilayer. It contains one saturated and one unsaturated chain in its structure. Phosphatidylethanolamine is cone shaped and doesn't form bilayer itself ⁽¹⁹⁾.

PHYSIOLOGICAL PROPERTIES OF PHOSPHOLIPIDS: The soya phospholipids are absorbed at a rate greater than 90% in humans and reach peak plasma concentration in about 6 h after oral administration. The maximum plasma concentration reached was found to be 20% of the dose administered^(30,31). Apart from a physiologically compatible pharmacokinetic and toxicological profile the dietary phospholipids also possess some medicinally significant properties in human beings. Phospholipids are a decent source of phosphatidylcholine and choline, both of which liquefy the fat dumped inside the liver in case of hepatic steatosis or fatty liver and exhibit other hepatoprotective effects as well ^(32,33) . The essential or soya phospholipids have shown to be hepatoprotective in nature and prevent liver damage by alcohol, drugs and other toxins ⁽³⁴⁾. They have also been reported to aid in clearance of serum cholesterol and increase circulating HDL levels in plasma ^{(35, 36)}.

PHYTOACTIVE CONSTITUENTS: ^{(37,38,39,40)}

1.Generally ,phytoconstituents or standardized plant extracts are selected for complexation but sometimes the natural products obtained after isolation and purification may leads to loss in their biological activity due to heat and solvent effect. Under such situation whole plant extract is selected. Usually, phytophospholipid complex formulations are prepared according to weight for standardized extract, whereas molar ratios for active constituent.

2. Selection of plant extract depends on its phytochemical (such as polyphenols, triterpenoids, tannins, alkaloids and saponins) and pharmacokinetic profile. Usually they have multiple ring molecules which are too large to be absorbed by simple diffusion and have low permeability across the cellular lines of the intestine.

3. A drug which contains an active hydrogen atom like –COOH, -OH, -NH2, -NH etc., which have the ability to form hydrogen bond between the drug and N-(CH3) of PC molecules.

4. Any drugs which possess π electrons can be formulated into different complexes with phospholipid molecules.

5. Both hydrophilic and lipophilic actives can be complexed to improve bioavailability.

SOLVENT: Different solvents have been used by formulation scientist as reaction medium for preparation of phyto-phospholipid complexes. Earlier aprotic solvents such as aromatic hydrocarbons, halogen derivatives, methylene chloride, ethyl acetate, or cyclic ethers furan derivatives etc. have been used to prepare phyto- phospholipid complexes but they have been largely replaced by protic solvents like ethanol^(41,42). Indeed, protonic solvents, such as ethanol and methanol, have been successfully utilized to prepare phospholipid complexes. For example, Xiao prepared silybin-phospholipid complexes using ethanol as a protonic solvent; subsequently, the pro-tonic solvent was removed under vacuum at 40 °C ⁽⁴³⁾.

STOICHIOMETRIC RATIO OF ACTIVE CONSTITUENTS AND PHOSPHOLIPIDS:

Normally, phyto-phospholipid complexes are employed by reacting a synthetic or natural phospholipid with the active constituents in a molar ratio ranging from 0.5 to 2.0 ⁽³²⁾. Whereas, a stoichiometric ratio or molar ratio of 1:1 is found to be the most efficient ratio for formulating phospholipid complexes ⁽⁴⁴⁾.

Yue et al. performed the comparative study by using the stoichiometric ratios of 1:1, 1.4:1, 2:1, 2.6:1, and 3:1 to generate oxymatrine-phospholipid complexes and further concluded that the optimal quantity was obtained at a ratio of 3:1⁽⁴⁵⁾. So that the stoichiometric ratio or molar ratio of 1:1 is not always optimal for the formulation of phospholipid complexes. Therefore, it can be concluded that the stoichiometric ratio is experimentally adjusted to get high drug entrapment or drug loading.

PHYTOACTIVE COMPOUNDS– PHOSPHOLIPID INTERACTION: The plant constituents or herbal extract specially polyphenolic compounds form complexes with phospholipid molecules by chemical bonds formation between phytoactive molecule and phospholipid. This can be proved or established by the thermal analysis of phytophospholipid complexes with respect to pure drug and phyto phospholipids physical mixture ⁽⁴⁶⁾. The OH group of phenolic rings existing in the structure of the phytocompounds/herbal extract is responsible for hydrogen bonding. Similarly the same conclusions was withdrawn from the studies of phospholipid complexes of naringenin, puerarin, gallic acid and gymnemic acid⁽⁴⁷⁾. Some researchers also suggested one more reason for the complexation, is the formation of Vander Waals forces between the two moieties ^(48,49)It has been proposed that the aqueous head of phosphatidylcholine molecule i.e. the choline binds to the water soluble compounds and the phosphatidyl portion being lipophilic encloses the choline bound structure ⁽⁴⁵⁾. The fact obtained from Experimentation that the molecules possessing conjugated systems of π electrons are capable of forming different complexes with cellular phospholipid molecules ⁽⁵⁰⁾.

This finding has been further established by the study of the interaction between 3,5,7,3′,4′-pentahydroxyflavonol or quercetin with lecithin which suggests that the change in chemical shifts of phosphatidylcholine because of its chemical interaction with quercetin is correlated with the interaction of π electrons of quercetin with the choline head and the phosphate group of phosphatidylcholine ⁽⁵¹⁾.

METHODS OF PHOSPHOLIPID COMPLEX PREPARATION: The following methods are used to develop phospholipid complex preparation like, solvent evaporation, anti solvent precipitation, mechanical dispersion methods.

Solvent evaporation method- In this method, phytoconstituents and phospholipids are taken in a flask containing organic solvent. This reaction mixture was kept at 40⁰C for specific time interval of 1 hr to attain maximum drug entrapment in the complex formed. The organic solvent was further removed by using rotary evaporator. The prepared complex was sieved by using 100 mesh sieves, and stored in desiccators for overnight for further use⁽²³⁾.

The resultant complex are stored in a air tight light resistant amber colored glass bottle, flushed with nitrogen at room temperature to attain stability ⁽¹⁸⁾.

Anti solvent precipitation method-This method is generally used, phytoconstituents and phospholid are taken in flask containing a organic solvent and the mixture is refluxed at a fixed temperature for specific period of time with constant stirring on a magnetic stirrer. The solution was concentrated and anti-solvent like n-hexane is added with stirring. the precipitate which is obtained as complex was filtered, dried and stored in an air tight amber colored glass container ^(52,53).

Mechanical dispersion method -In this method, the phospholipids dissolved in organic solvent and lipid solution was injected into aqueous phase containing the phytocompound to be encapsulated⁽⁵⁴⁾. Further the organic solvent is removed under reduced pressure leads to the formation of phytophospholipid complex.The novel method has been developed for phospholipd complexation includes super critical fluids (SCF). This is an effective tool for preparing particles of size ranging from 5 to 2000 nm. Different methods of supercritical fluid have been utilized, which include gas anti-solvent technique (GAS) to improve solubility profiles of poorly soluble drug candidates.

OPTIMIZATION AND CHARACTERIZATION TECHNIQUES: Optimization of Phospholipids complex formulation depends on various factors like molar ratio of drug to phospholipid, selection of solvent duration of time, temperature, rotational speed (in solvent evaporation method), type of drying method employed. All these parameters are optimized statistically through quality by design (QbD) ^{(55, 56)}.

CHARACTERIZATION OF PHYTO-PHOSPHOLIPID COMPLEXES:

Yield (complexation rate) of phyto-phospholipid complexes-The percentage yield of phytoactive constituents or herbal components in phytophospholipid complex is imporatnt parameter to represents an important index to know the complexation rate.The differance in weight between the initial phyto active constituent and free compounds is the amount of active constituent present in phytophospholipid complex .

The formula is as follows:

Yield ( % ) = [ (A −B ) /A ] ×100%

Where “A ”is the initial weight of active constituent,

“B ”is the weigh free active constituent, and “( A –B )”is the weight of the phospholipid complexes ⁽⁴⁶⁾.

Solubility and partition coefficient -The solubility in either water or organic solvents and the n-octanol/water partition coefficient (P) partition coefficient study of phytoactive dug as well as their complex with phospholid complex and physical mixture with lipid is prerequiste parameter to identify the lipiphillicity and hydrophillicity nature of drug and their complex formulation. Generally, phyto-phospholipid complexes have better lipophilicity and hydrophilicity than active constituents, so that it shows the better absorption and bioavailability ⁽⁵⁷⁾.

Entrapment efficiency⁽⁵⁸⁾- The drug entrapment efficiency is calculated by ultra centrifugation technique where certain amount of phyto-phospholipid complex is weighed equivalent to the quantity of active drug that is encapsulated and added to phosphate buffer (pH 6.8).

The buffer containing the complex was stirred on a magnetic stirrer for specific period of time and allowed to stand for one hour. further the clear liquid is decanted off and centrifuged at 5000 rpm for 15 minutes. The supernatant is filtered through 0.45μ Whatman filter paper and tha their absorbance was measured by using UV or HPLC.

The drug entrapment percentage (%) is calculated by using the following formula:

Drug entrapment (%)= Actual amount determined/ Theoretical amount present.

Particle size and zeta potential - Particle size and zeta potential are important characterization parameter of complexes that are directly related to stability and reproducibility of formulation. Generally, the average particle size of phospholipid complexes ranged from 50 nm to 100 μm. Mazumder developed sinigrin loaded phytophospholipid complexes, and concluded that the average particle size and zeta potential of the complex were 153 ±39 nm and 10.09 ±0.98 mV, respectively ⁽⁵⁹⁾.

X-ray diffraction⁽⁸⁾- Currently, X-ray diffraction is an effective tool to determine the microstructure of both crystal materials and some amorphous materials. X-ray diffraction is usually performed on either active constituents or phyto phospholipid complexes, PCs and their physical mixtures.

Differential scanning calorimetry (DSC)- In DSC study,the interactions between active constituents and phospholipid can be identified by comparing the transition temperature, appearance of new peaks, disappearance of original peaks, melting points, and changes in the relative peaks area ⁽⁴⁶⁾.

Phyto-phospholipid complexes usually showed the different characteristic peaks, when compared with the physical mixture or pure drug. Further It can be assumed that, strong interactions of phytocompound and phospholipids occur. Das and Kalita formulated rutin phyto-phospholipid complexes and the DSC thermogram showed two different characteristic peaks that were lower than that of the physical mixture and rutin and PC disappeared ⁽⁶⁰⁾.

Scanning electron microscopy (SEM) and transmission electron microscopy (TEM)- Scanning electron microscopy (SEM) analysis showed surface morphological structure of solid state properties complexes. whereas transmission electron microscopy TEM is used to determine the crystalline nature and dispersion of nanomaterials further it is used to measure the particle size of nanoparticles. SEM study reflects that active compounds can be visualized in a highly crystalline state, but the shaped crystals disappeared after complexation,when diluted in distilled water under slight shaking, TEM showed that phyto-phospholipid complexes exhibit vesicle-like structures ⁽⁶¹⁾.

SPECTROSCOPIC ANALYSIS (STRUCTURAL VERIFICATION):

To confirm the formation of a complex or to study the reciprocal interaction between the phytoconstituent and the phospholipids, the following spectroscopic methods are used .

Ultraviolet spectra (UV-spectra)- Pure compounds and their complex samples that reflect different absorption maxima in the UV wavelength range are often used to characterize their own structural properties. Most of the studies have revealed that there no markedly differences in their UV absorption characteristics of constituents before and after complexation. Xu et al. prepared luteolin loaded phospholipid complexes and conclude from result obtain from study that the characteristic peaks of luteolin remained present ⁽²⁴⁾. Therefore, it is proved that the chromophores of components are not affected by complexation with phospholipids.

Fourier transform infrared spectroscopy (FTIR)-Generally it is used for for structural analysis and presence or absence of functional group that reflects the distinct characteristics in band number, position, shape, and intensity The formation of the phyto phospholipid complex can be also be confirmed by FTIR spectroscopy by comparing the spectrum of the complex with the spectrum of the individual components and their physical mixtures.⁽⁴³⁾. The FT-IR spectra of the active phytoconstituent, the phospholipid and their phytophospholipid complex are compared. The free hydroxyl group interact with the choline part of phospholipid. The peak corresponding to the free hydroxyl group changes and a broad peak appears instead. ⁽⁶²⁾.

NUCLEAR MAGNETIC RESONANCE (NMR):

(A) 1H-NMR: The complexation between the active phytoconstituents and the phospholipd molecule can be determined by this method. Bombardelli et al., studied the NMR spectra of complex in non polar solvents. There is a marked change in 1H-NMR signal originating from atoms involved in the formation of complex, without any summation of the signal peculiar to individual molecules. The signals from protons belonging to the phytoconstituents are broadened. In phospholipids there is broadening of signals while the singlet corresponding to the N-(CH3)3 of choline undergoes an up field shift ⁽²⁵⁾_.

(B) 13C-NMR: In the 13C NMR of the phytoconstituents and the stoichiometric complex with the phosphatidylcholine when recorded in C6D6 at room temperature, all the phytoconstituent carbons were invisible. The signals corresponding to the glycerol and choline portion are broadened and some are shifted, while most of the resonance of the fatty acid chains retains their original sharp line shape ^(26,27,28).

IN-VITRO AND IN-VIVO EVALUATIONS: The models for in-vitro and in-vivo evaluations are selected on the basis of the expected therapeutic activity of the biologically active phytoconstituents present in the phytophospholipid complex ⁽²⁹⁾. For example, in-vitro anti hepatotoxic activity can be assessed by the antioxidant and free radical scavenging activity of the phytosomes. For assessing anti hepatotoxic activity in-vivo, the effect of prepared phytosomes on animals against thioacetamide, paracetamol alcohol induced hepatoxicity can be examined ^{(19, 30)}.

DISCUSSION:

The phyto-phospholipid complexation method has an effective tool for improving bioavailability of phytocompounds or herbal extracts. This novel approach facilitates the preparation of herbal drugs that have sufficient lipid penetrability at higher concentration and sustained therapeutic levels in plasma with a slower rate of elimination. Phospholipids used as a carrier, having affinity for active constituents through hydrogen bond interactions. From the research it was found that the phospholipid complex technique is not limited to only polyphenolsbut also for any plant active molecules. By the phytophospholipid complexation techniques the more amount of drug has been made available at the site of action. However, it has few limitations which includes a lack of mechanistic connection, quantitative guidance regarding when the lipid-based systems will enhance bioavailability and how to formulate drugs to achieve the desired impact. So the potential of phytophospholipid complexes, with the effort researchers and scientists, has a bright future for applications in the pharmaceutical field.

CONFLICT OF INTEREST:

Authors declared no conflict of interest.

REFERENCES:

1. Ajazuddin , Saraf S. Applications of novel drug delivery system for herbal formulations. Fitoterapia.2010; 81:680–689.

2. Teng Z ,Yuan C ,Zhang F ,Huan M ,Cao W ,Li K ,et al.Intestinal absorption and first-pass metabolism of polyphenol compounds in rat and their transport dynamics in caco-2 cells. PLoS One 2012; 7(1):e29647.

3. Manach C ,Scalbert A ,Morand C ,Rémésy C ,Jiménez L . Polyphenols: food source and bioavailability. Am J Clin Nutr 2004; 79(5):727–47 .

4. Manach C, Williamson G, Morand C, Scalbert A, Remesy C. Bioavailability and bioefficacy of polyphenols in humans. I. Review of 97 bioavailability studies, Am. J. Clin. Nutr. 2005; (81):230S–242S.

5. Karakaya S. Bioavailability of phenolic compounds, Crit. Rev. Food Sci. Nutr. 2004; (44):453–464.

6. Battacharya S. Phytosome: Emerging strategy in delivery of herbal drugs and nutraceuticals. PharmTimes.2009;41(3):9-12

7. Mei Lu, Qiujun Q , Xiang Luo , Xinrong Liu , Jing Sun , Wang C , Xiangyun Lin , Deng Y , Song Y. Phyto-phospholipid complexes (phytosomes): A novel strategy to improve the bioavailability of active constituents Asian journal of pharmaceutical sciences. 2018:20-35

8. Ting Y, Jiang Y, Ho CT, Huang Q. Common delivery systems for enhancing in vivo bioavailability and biological efficacy of nutraceuticals. J Funct Foods. 2014;(7):112–28

9. Wei L, Kelly AL, Song M. Emulsion-based encapsulation and delivery systems for polyphenols. Trends Food Sci Tech. 2016; (47):1–9 .

10. Munin A, Edwards-L F. Encapsulation of natural polyphenolic compounds: a review. Pharmaceutics. 2011; 3(4):793–829.

11. Zeng L, He J L ,Luo LY , . Recent advances in research on preparation technologies and applications of tea polyphenol nanoparticles. Food Sci. 2011;(32):317–22 .

12. Lambert JD, Sang S, Hong J, Kwon SJ, Lee MJ, Ho CT, Yang CS.Peracetylation as a means of enhancing in vitro bioactivity and bioavailability of epigallocatechin-3-gallate. Drug Metab Dispos. 2006 ;34(12):2111–6.

13. Mulholland PJ, Ferry DR, Anderson D, Hussain SA, Young AM, Cook JE, Hodgkin E, Seymour LW, Kerr DJ. Pre-clinical and clinical study of QC12, a water-soluble, pro-drug of quercetin. Ann Oncol. 2001; 12(2):245–8.

14. Kidd P, Head K. A review of the bioavailability and clinical efficacy of milk thistle phytosome: a silybin-phosphatidylcholine complex (Siliphos). Altern Med Rev. 2005; 10(3):193–203.

15. Chen ZP,Sun J,Chen HX ,Xiao YY ,Dan L ,Chen J . Comparative pharmacokinetics and bioavailability studies of quercetin, kaempferol and isorhamnetin after oral administration of Ginkgo biloba extracts, Ginkgo biloba extract phospholipid complexes and Ginkgo biloba extract solid dispersions in rats. Fitoterapia.2010; 81(8):1045–52.

16. Yue PF, Yuan HL, Yang M, Zhu WF. Preparation, characterization and pharmacokinetics in vivo of oxymatrine–phospholipid complex. J Bioequiv Availab. 2009; (1):99–102.

17. Maiti K ,Mukherjee K ,Gantait A ,Saha BP ,Mukherjee PK . Curcumin–phospholipid complex: preparation, therapeutic evaluation and pharmacokinetic study in rats. Int J Pharma. 2007; 330(1–2):155–63.

18. Xiao Y, Song Y, Chen Z, Ping Q. The preparation of silybin-phospholipid complex and the study on its pharmacokinetics in rats. Int J Pharma 2006;307(1):77–82

19. Virtanen J.A, Cheng K.H, Somerharju P. Phospholipid composition of the mammalian red cell membrane can be rationalized by a superlattice model, Proc Natl. Acad. Sci. U. S. A; 1998;(95): 4964–4969.

20. Kidd PM. Bioavailability and activity of phytosome complexes from botanical polyphenols: the silymarin, curcumin, green tea, and grape seed extracts, Altern.

21. Pandey S, Kinjal P. Phytosomes: technical revolution in phytomedicine. Int. J. PharmTech Res. 2010; (2): 627-631.

22. Li J, Wang X, Zhang T, Wang C, Huang Z, Luo X. A review on phospholipids and their main applications in drug delivery systems. Asian J Pharma Sci 2015; 10(2):81–98

23. Ghanbarzadeh B, Babazadeh A , Hamishehkar H. Nano-phytosome as a potential food-grade delivery system. Food Biosci 2016;(15):126–35 .

24. Suriyakala PC, Babu NS, Rajan DS, Prabakaran L. Phospholipids as versatile polymer in drug delivery systems. Int J Pharm Pharm Sci. 2014;6(1):8–11

25. Duric M , Sivanesan S , Bakovic M . Phosphatidylcholine functional foods and nutraceuticals: a potential approach to prevent non-alcoholic fatty liver disease. Eur J Lipid Sci Tech. 2012; 114(4):389–98.

26. McIntosh TJ, Simon SA, Needham D. Structure and cohesive properties of sphingomyelin/cholesterol bilayers.Biochemistry. 1992; 31(7):2012-2020.

27. Barenholz Y, Thompson TE. Sphingomyelin: biophysical aspects. Chem Phys Lipids 1999; 102(1):29-34.

28. Jain NK, Controlled and Novel Drug Delivery, CBS Publisher, II ed, 2005; 321-326

29. Chauhan NS, Gowtham R, Gopalkrishna B. Phytosome: A potential phyto-phospholipid carriers for herbal drug delivery. J. Pharm Res .2009 ;(2):1267-1270.

30. Acharya NS, Parihar GV, Acharya SR. Phytosomes: novel approach for delivering herbal extract with improved bioavailability, Pharma Sci. Monit. 2011;(2):144-160.

31. Vanmeer G, Kroon AI De. Lipid map of the mammalian cell, J. Cell Sci. 2011;(124) :5-8.

32. Zierenberg O, Grundy SM. Intestinal absorption of polyenylphosphatidylcholine in man, J. Lipid Res. 1982 ;( 23):1136-1142.

33. Silki, Kapoor D , Malviya S, Talwar V, Katare O P. Potential and promises of phospholipid structured novel formulations for hepatoprotection, Int. J. Drug Dev Res. 2012 ;(4):51-58.

34. Gundermann KJ, Kuenker A, Kuntz E, Drozdzik M. Activity of essential phospholipids (EPL) from soybean in liver diseases, Pharmacol. Rep. 2011;(63): 643-659.

35. Semalty A, Semalty M, Rawat BS, Singh D, Rawat MSM. Pharmacosomes: the lipid-based novel drug delivery system. Expert Opin Drug Deliv. 2009; 6(6):599-612.

36. Cohn JS, Wat E, Kamili A, Tandy S. Dietary phospholipids, hepatic lipid metabolism and cardiovascular disease, Curr. Opin. Lipidol. 2008;(19):257–262

37. Bombardelli E, Cristoni A, Morazzoni P. Phytosomes in functional cosmetics. Fitoterapia. 1994; 65(5):387-401.

38. Sarika D, Khar RK, Chakraborthy GS, Saurabh M. Phytosomes: A Brief overview. J Pharm Res. 2016; 15(2):56-62.

39. Afanaseva YG, Fakhretdinova ER, Spirikhin LV, Nasibullin RS. Mechanism of interaction of certain flavonoids with phosphatidylcholine of cellular membranes. Pharm Chem J. 2007; 41(7):354-6.

40. Khan J, Alexander A, Saraf S, Saraf S. Recent advances and future prospects of phyto-phospholipid complexation technique for improving pharmacokinetic profile of plant actives. J Control Release. 2013; 168(1):50–60.

41. Shakeri A , Sahebkar A . Phytosome: a fatty solution for efficient formulation of phytopharmaceuticals. Recent Pat Drug Deliv Formul 2016; 10(1):7–10.

42. Xiao Y, Song Y, Chen Z, Ping Q. The preparation of silybin-phospholipid complex and the study on its pharmacokinetics in rats. Int J Pharma. 2006; 307(1):77–82.

43. Tripathy S, Patel DK , Barob L, Naira SK. A review on phytosomes, their characterization, advancement & potential for transdermal application. J Drug Deliv Ther. 2013; 3(3):147–52.

44. Zhang K , Zhang M , Liu Z , Zhang Y , Gu L , Hu G , et al. Development of quercetin-phospholipid complex to improve the bioavailability and protection effects against carbon tetrachloride-induced hepatotoxicity in SD rats. Fitoterapia. 2016;(113):102–9 .

45. Semalty A, Semalty M, Rawat MS, Franceschi F. Supramolecular phospholipids– polyphenolics interactions: The Phytosome strategy to improve the bioavailability of phytochemicals, Fitoterapia.2010 ;(81):306–314.

46. Pathan R, Bhandari U. Preparation characterization of embelin phospholipid complex as effective drug delivery tool, J. Incl. Phenom. Macrocycl. Chem.2011 ;( 69): 139–147.

47. Semalty A, Semalty M, Singh D, Rawat MSM. Phyto-phospholipid complex of catechin in value added herbal drug delivery, J. Incl. Phenom. Macrocycl. Chem. 2012;(73): 377–386.

48. Alexander A, Tripathi DK, Verma T, Swarna, Maurya J, Patel S. Mechanism responsible for mucoadhesion of mucoadhesive drug delivery system: a review, Int. J. Appl. Biol. Pharm. Technol. 2011;( 2 ): 434–445

49. Tripathy S, Patel DK , Baro L, Nair SK. A Review On Phytosomes, Their Characterization, Advancement & Potential For Transdermal Application Journal of Drug Delivery & Therapeutics. 2013;3(3): 147-152

50. Nasibullin RS, Nikitina TI, Afanaseva YG, Nasibullin TR, Spirikhin LV. Complex of 3,5,7,3′,4′-pentahydroxyflavonol with phosphatidylcholine, Pharm. Chem. J.2002; (36): 492–495.

51. Tan Q, Liu S, Chen X, Wu M, Wang H, Yin H. Design and evaluation of a novel evodiamine-phospholipid complex for improved oral bioavailability. AAPS PharmSciTech 2012; 13(2):534-47.

52. Saoji SD, Belgamwar VS, Dharashivkar SS, Rode AA, Mack C, Dave VS. The Study of the Influence of Formulation and Process Variables on the Functional Attributes of Simvastatin–Phospholipid Complex. J Pharm Innov. 2016; 11(3):264-78.

53. Sikarwar MS, Sharma S, Jain AK, Parial SD. Preparation, characterization and evaluation of marsupsin-phospholipid complex. AAPS PharmSciTech. 2008; 9(1):129-37.

54. Y. Li, Chen SL, Chen SB, Chan AS. Process parameters and morphology in puerarin, phospholipids and their complex microparticles generation by supercritical antisolvent precipitation, Int. J. Pharm.2008; (359): 35–45.

55. Ajazuddin, Alexander A, Khan J, Giri TK, Tripathi DK, Saraf S. Advancement in stimuli triggered in situ gelling delivery for local and systemic route, Expert Opin. Drug Deliv. 2012; (9): 1573–1592.

56. Saoji SD, Raut NA, Dhore PW, Borkar CD, Popielarczyk M, Dave VS. Preparation and evaluation of phospholipid-based complex of standardized centella extract (SCE) for the enhanced delivery of phytoconstituents. AAPS j. 2016; 18(1):102-14.

57. Pu Y, Zhang X, Zhang Q, Wang B, Chen Y, Zang C, Wang Y, Dong TT, Zhang T. 20(S)-Protopanaxadiol Phospholipid Complex: Process Optimization, Characterization, In Vitro Dissolution and Molecular Docking Studies. Molecules. 2016; 21(10):1396.

58. Hao H ,Jia Y ,Han R ,Amp IA . Phytosomes: an effective approach to enhance the oral bioavailability of active constituents extracted from plants. J Chin Pharm Sci. 2013;22(5):385–92 .

59. Das MK, Kalita B. Design and evaluation of phyto-phospholipid complexes (phytosomes) of rutin for transdermal application. J J Appl Pharm Sci 2014;4(10):5

60. Xu K ,Liu B ,Ma Y ,Du J ,Li G ,Gao H. Physicochemical properties and antioxidant activities of luteolin-phospholipid complex. Molecules 2009; 14(9):3486–93.

61. Patial A, Rana M ,Bhandari N. Role of phytosome in human health. world journal of pharmacy and pharmaceutical sciences. 2018;7(10): 680-691.

62. Doering T, Traeger A, Waldmann L. Cosmetic and dermatological composition for the treatment of aging or photodamaged skin. EP1640041 ;2006.

63. Comoglio A, Tomasi A, Malandrino S, Poli G, Albano E Scavenging effect of silipide-A new silybin-phospholipid complex on ethanol derived free radicals, Biochem. Pharmacol. 1995;(50): 1313-1316.

64. Cevc G, Schatzlein A, Blume G Transdermal Drug Carriers: Basic Properties,Optimization and Transfer Efficiency in Case of Epicutaneously Applied Peptides. J.Control Release.1995;(36): 3-16.

65. Maghraby GM, Williams EC, Barry BW. Oestradiol skin delivery from ultradeformable liposomes: refinement of surfactant concentration. Int. J.Pharm. 2000; (196): 63-74.

66. Fry DW, White JC, Goldman ID Rapid Sectretion of Low Molecular Weight Solute from Liposomes without Dilution. Anal.Biochem.1978;90: 809-815

Received on 27.06.2019 Modified on 11.09.2019

Research J. Pharm. and Tech 2020; 13(2):1059-1066.

DOI: 10.5958/0974-360X.2020.00195.X

TITLE	INNOVATION	PATENT NO	REFERENCE
Phospholipid complexes of olive fruits or leaves extracts having improved bioavailability	Phospholipid complexes of olive fruits or leaves extracts or compositions containing it having improved bioavailability	EP/1844785	(62)
Compositions comprising Ginkgo biloba derivatives for the treatment of asthmatic and allergic conditions	Compositions containing fractions deriving from Ginkgo biloba, useful for the treatment of asthmatic and allergic conditions	EP1813280	(63)
Fatty acid monoesters of sorbityl furfural and compositions for cosmetic and dermatological use	Fatty acid monoesters of sorbityl furfural selected from two diff series of compounds in which side chain is a linear or branched C3-C19 alkyl radical optionally containing at least one ethylenic unsaturation least one ethylenic unsaturation.	EP1690862	(21)
Cosmetic and dermatological composition for the treatment of aging or photo damaged skin	Composition for topical treatment of the skin comprises a substance that stimulates collagen synthesis and a substance that enhances the interaction between extracellular matrix and fibroblasts Cosmetic or dermatological composition for topical treatment	EP1640041	(64)
Treatment of skin, and wound repair, with thymosin β4.	Compositions and methods for treatment of skin utilizing thymosin β4	US/2007/ 0015698	(6)
Soluble isoflavone compositions	Isoflavone compositions exhibiting improved solubility (e.g., light transmittance), taste, colour, and texture characteristics, and methods for making the same	WO/2004/ 045541	(29)
An anti-oxidant preparation based on plant extracts for the treatment of circulation and adiposity problems.	Preparation based on plant extracts which has an anti-oxidant effect and is particularly useful in treatment of circulation problems such as phlebitis, varicosevein, arteriosclerosis, haemorrhoid and high blood pressure	EP1214084	(65)
Complexes of saponins with phospholipid and pharmaceutical and cosmeticcompositions containing them	Complexes of saponins with natural or synthetic phospholipid have high lipophilic and improved bioavailability and are suitable for use as active principle in pharmaceutical, dermatologic and cosmetic compositions	EP0283713	(66)