Supramolecular phospholipids-polyphenolics interactions: the PHYTOSOME strategy to improve the bioavailability of phytochemicals

Phytosome Containing Silymarin for Oral Administration: Formulation and Physical Evaluation

Silymarin is a unique flavonoid complex isolated from milk thistle (Silybum marianum). It has been widely used as a hepatoprotective agent. Orally administered silymarin can be absorbed rapidly but only 20-50% of silymarin will be absorbed through gastrointestinal tract, resulting in low bioavailability. Those limitations are due to its low solubility, either in water and oil, and its low intestinal permeability. This study was aimed to develop silymarin-containing phytosome in order to improve the bioavailability of silymarin with sufficient safety and stability. This system consisted of silymarin-phospholipid complex prepared by solvent evaporation method, which was incorporated to form phytosome vesicles using thin layer method with various concentrations and molar ratios of silymarin and phospholipid. The vesicle size of phytosome was reduced with sonication. The results demonstrated that formula with 2% silymarin-phospholipid complex and molar ratio of silymarin to phospholipid of 1:5 showed the best phytosomal characteristics, with mean vesicle diameter of 133.534 ± 8.76 nm, polidispersity index of 0.339 ± 0.078, entrapment efficiency of 97.169 ± 2.412 %, and loading capacity of 12.18 ± 0.30 %. The preparation remained stable after freeze-thaw stability test. Analysis of Infrared spectroscopy and Differential Scanning Calorimetry confirmed the presence of physical and chemical interactions between silymarin and phospholipid within complex formation. Well formed and discrete vesicles were revealed by Transmission Electron Microscopy analysis, drug content measurement, and freeze-thaw stability test.

Anti-inflammatory potential of a lipid-based formulation of a rotenoid-rich fraction prepared from Boerhavia diffusa

CONTEXT

Boerhavia diffusa L. (Nyctaginaceae) roots are used in Ayurveda for treating inflammatory diseases. Generally poor oral bioavailability is a major problem associated with herbal drugs.

OBJECTIVE

To develop a phospholipid complex of rotenoid-rich fraction (RRF) and evaluate its in vivo anti-inflammatory activity and pharmacokinetic study.

MATERIALS AND METHODS

RRF was prepared from a 70% ethanol extract of B. diffusa roots. This RRF was complexed with phosphatidylcholine by refluxing in 70% ethanol. In vivo anti-inflammatory activity of RRF-PC and RRF was determined using the carrageenan-induced rat paw edema method, at a dose equivalent to 100 mg/kg p.o. of RRF. Edema volume was calculated at 3 and 5 h. The plasma concentration of boeravinone B was estimated in rats at a same dose level. Blood samples were collected at 1, 2, 4, 6, 8, 10, 12, 24, and 36 h.

RESULTS

(1)H and (31)P NMR spectra of RRF-PC showed up-field shift of protons of the (+)N(CH3)3 group (3.37 → 3.23) and the phosphorus atom (-1.26 → -1.57 ppm), respectively, which confirmed phospholipid complex formation between phosphatidylcholine [PO4 and (+)N(CH3)3 groups] and phytoconstituents by hydrogen bonding. The RRF-PC showed significantly enhanced in vivo anti-inflammatory activity (64%) as compared with RRF (48%) and ibuprofen (50%) at 5 h (p < 0.001). Furthermore, detected plasma concentration of boeravinone B was two times higher in RRF-PC (75 ng/mL) as compared with RRF (40 ng/mL).

CONCLUSION

The present study demonstrated an increased anti-inflammatory potential and higher plasma level of boeravinone B in lipid-based formulation (RRF-PC) as compared with RRF.

Bioavailability of dietary polyphenols: Factors contributing to their clinical application in CNS diseases

The anatomical location of the central nervous system (CNS) renders it immunologically and pharmacologically privileged due to the blood brain barrier (BBB). Although this limits the transport of unfavorable molecules to the CNS, the ensuing privilege could be disadvantageous for therapeutic compounds. Hence, the greatest challenge in the pharmacotherapy of CNS diseases is to ensure efficient brain targeting and drug delivery. Research evidences indicate that dietary polyphenols have neuroprotective potential against CNS diseases. However, their selective permeability across BBB, poor absorption, rapid metabolism and systemic elimination limit their bioavailability and therapeutic efficacy. Consequently, the beneficial effects of these orally administered agents in the CNS still remain a subject of debate. This has also limited its clinical application either as independent or adjunctive therapy. Improving the in vivo bioavailability by novel methods could improve the therapeutic feasibility of polyphenols and assist in evolving novel drugs and their derivatives with improved efficacy in vivo. Here we review the mechanistic and pharmacological issues related to the bioavailability of polyphenols with therapeutic implications for CNS diseases. We surmise that improving the bioavailability of polyphenols entails efficient in vivo transport across BBB, biochemical stability, improved half-life and persistent neuroprotection in the CNS.

Polyphenolics-Phospholipid Complexes as Natural Cosmetic Ingredients: Properties and Application

Phospholipids and polyphenolic phytoconstituents may form specific molecular complexes (polyphenolics-phospholipid complexes, phyto-phospholipid complexes) with definite chemical structure, solubility, thermal and spectroscopic characteristics. Furthermore, such specific molecular entities may self-associate into spherical unilamellar vesicles (phyto-vesicles, herbosomes) with size at nano- or microscale. Phyto-phospholipid complexation was recognised as a promising strategy to improve formulation performances and enhance efficiency of herbal polyphenolics with cosmetic relevance in comparison with pure phytoconstituents. This concise review summarizes the current knowledge on preparation methods, physico-chemical properties and aspects of application of the selected phyto-complexes as cosmetic active ingredients.

Beyond Yellow Curry: Assessing Commercial Curcumin Absorption Technologies

BACKGROUND: Few natural products have demonstrated the range of protective and therapeutic promise as have turmeric and its principal bioactive components: curcumin, demethoxycurcumin, and bisdemethoxycurcumin. Success in translating this potential into tangible benefits has been limited by inherently poor intestinal absorption, rapid metabolism, and limited systemic bioavailability. Seeking to overcome these limitations, food ingredient formulators have begun to employ a variety of approaches to enhance absorption and bioactivity. Many of these strategies improve upon the age-old practice of consuming turmeric in fat-based sauces, such as in a fat-rich yellow curry. However, there exists uncertainty as to how the various commercially available offerings compare to each other in terms of either uptake or efficacy, and this uncertainty leaves physicians and nutritionists with a dearth of data for making recommendations to interested patients and consumers. Further complicating the issue are recent data suggesting that formulation strategies may not equally enhance the absorption of individual curcuminoids, a significant issue in that these curcuminoids exhibit somewhat different physiologic properties.

OBJECTIVE: This review introduces needed order to the curcumin marketplace by examining bioavailability studies on a number of commercial curcumin ingredients and evaluating them on a level playing field.

METHODS: The comparative analysis includes standard pharmacokinetic parameters and a new metric, relative mass efficiency (E). Relative mass efficiency allows for the comparison of different formulations even in cases in which the weight percentage of curcuminoids is vastly different.

RESULTS: A hydrophilic carrier dispersed curcuminoid formula exhibits 45.9 times the bioavailability of the standard purified 95 percent curcuminoid preparation and, based on relative mass efficiency, 1.5 times the bioavailability of the next best commercial ingredient, a cyclodextrin complex.

CONCLUSIONS: Delivery strategies can significantly improve the bioavailability of curcuminoids. Total formula mass is important for making practical formulation decisions about dosing, cost and space.

Antioxidant and hepatoprotective effects of mixed micellar lipid formulation of phyllanthin and piperine in carbon tetrachloride-induced liver injury in rodents

Phyllanthin, a sparingly water-soluble hepatoprotective lignin obtained from Phyllanthus amarus Schum. et Thonn. (Euphorbiaceae) possesses low bioavailability.

A cosmeceutical formulation based on boswellic acids for the treatment of erythematous eczema and psoriasis

Background

Boswellic acids (BAs) show anti-inflammatory properties in a variety of inflammatory diseases, including rheumatoid arthritis, osteoarthritis, and asthma. A topical administration route is currently used to deliver active compounds in psoriatic and eczematous patients. In this double-blind study we compare a novel BA formulation (containing Bosexil^®, INCI [International Nomenclature of Cosmetic Ingredients]: lecithin, Boswellia serrata resin extract) with a placebo formulation. A third arm of the trial received a formulation of Vaccinium myrtillus seed oil, previously demonstrated as an effective local treatment for psoriatic lesions.

Methods

Patients with psoriasis or erythematous eczema were randomly assigned, in a 1:1:1 ratio, to Bosexil^®, V. myrtillus seed oil, or placebo. In order to evaluate the effects of treatment, the changes of scales and erythema from diagnosis to the end of treatment were scored in psoriatic patients, while changes in itch and erythema were analyzed for erythematous eczema patients. Psoriasis Area Severity Index and Eczema Area and Severity Index scores were also calculated.

Results

In patients with psoriasis, scales and erythema improved both with Bosexil^® and the V. myrtillus seed oil treatment in comparison with placebo. In particular, the treatment with Bosexil^® formulation improved scales (70% of cases) and erythema (50% of cases) without any case of worsening. In patients with eczema, the administration of placebo did not result in any improvement in 90% of cases, and in the remaining 10% worsened both itch and erythema. Bosexil^® formulation improved both itch (60% of cases) and erythema (60% of cases) without any case of worsening. V. myrtillus seed oil improved itch and erythema in 66.7% and 77.8% of patients, respectively.

Conclusion

A topical formulation of Bosexil^® may be promising for the treatment of psoriasis and erythematous eczema. Long-term studies are recommended to evaluate the adherence to this topical treatment and its clinical benefits in real life.

Luteolin-phospholipid complex: preparation, characterization and biological evaluation

OBJECTIVES

This study aims to develop novel carrier system incorporating luteolin, a poorly soluble biologically active plant active.

METHODS

We investigated a lipid-based drug delivery system to enhance dissolution and absorption profile of luteolin. Luteolin was complexed with phospholipids, and the preparation was characterized. The formulation was evaluated for physicochemical properties, in-vitro solubility or release studies. In vivo anti-inflammatory action of luteolin and its phospholipid complex was evaluated by using carrageenan and 12-O-tetradecanoylphorbol-13-acetate as inducers.

KEY FINDINGS

The prepared luteolin-phospholipid complex (LPC) showed drug loading of about 72.64% with average particle size of 152.6 nm. The Fourier transform infrared spectroscopy and thermal studies confirm formation of complex. The solubility of luteolin as LPC was about 2.5 times higher than the solubility of pure luteolin in water. In the diffusion study, LPC showed 95.12% of drug release at the end of 2 h. Animal studies demonstrated significant differences in response of LPC and luteolin.

CONCLUSION

LPC was successfully prepared by optimizing the process parameters. The resultant delivery system improved bioavailability and efficacy of luteolin and in the future may become an efficient tool for administration of luteolin.

Cyclodextrin and phospholipid complexation in solubility and dissolution enhancement: a critical and meta-analysis

INTRODUCTION

Poor solubility and dissolution of drugs are the major challenges in drug formulation and delivery. In order to improve the solubility and dissolution profile of drugs, various methods have been investigated so far. The cyclodextrin (CD) complexation and phospholipid (PL) complexation are among the exhaustively investigated methods employed for more precise improvement of the solubility and dissolution of poorly water-soluble drugs.

AREAS COVERED

The article discusses the CD and PL complexation techniques of solubility and dissolution enhancement. Various studies reporting the CD and PL complexation as the potential approaches to improve the dissolution, absorption and the bioavailability of the drugs have been discussed. The article critically reviews the physicochemical properties of CDs and PLs, eligibility of drugs for both the complexation, thermodynamics of complexation, methods of preparation, characterization, advantages, limitation and the meta-analysis of some studies for both the techniques.

EXPERT OPINION

The CD and PL complexation techniques are very useful in improving solubility and dissolution (and hence the bioavailability) of biopharmaceutical classification system Class II and Class IV drugs. The selection of a particular kind of complexation can be made on the basis of eligibility criteria (of drugs) for the individual techniques, cost, stability and effectiveness of the complexes.

Combined use of phospholipid complexes and self-emulsifying microemulsions for improving the oral absorption of a BCS class IV compound, baicalin

The aim of this study was to develop a formulation to improve the oral absorption of baicalin (BA) by combining a phospholipid complex (PC) and self-emulsifying microemulsion drug delivery system (SMEDDS), termed BA–PC–SMEDDS. BA–PC was prepared by a solvent evaporation method and evaluated by complexation percentage (CP). The physicochemical properties of BA–PC were determined. The synergistic effect of PC and SMEDDS on permeation of BA was studied in vitro with Caco-2 cells and in situ with a single pass intestinal perfusion model. The improved bioavailability of BA in BA–PC–SMEDDS was confirmed in an in vivo rat model. The CP of BA–PC reached 100% when the molar ratio of drug to phospholipid (PP) was ≥1:1. The solubility of BA–PC increased in both water and octanol, and the log P_o/w of BA–PC was increased significantly. BA–PC–SMEDDS could be dispersed more evenly in water, compared to BA and BA–PC. Both the Caco-2 cell uptake and single-pass intestinal perfusion models illustrated that transport of BA in BA–PC was lower than that of free BA, while improved significantly in BA–PC–SMEDDS. The relative bioavailability of BA–PC(1:2)–SMEDDS was 220.37%. The combination system of PC and SMEDDS had a synergistic effect on improving the oral absorption of BA.

Roles of chemical complexity and evolutionary theory in some hepatic and intestinal enzymatic systems in chemical reproducibility and clinical efficiency of herbal derivatives

Despite the great marketing success, most physicians attribute poor efficacy to herbals. This perception is due to two situations that are an integral part of the herbal topic. The first is the poor phytochemical reproducibility obtained during the production process of herbal extracts, as herbal extracts are not always standardized in the whole manufacturing process, but only in their titer. The second problem is linked to the evolution of important enzymatic systems: cytochromes and ABC proteins. They are both enzyme classes with detoxifying properties and seem to have evolved from the molecular mould provided by active plant substances. During the evolution, as still happens today, polyphenols, saponins, terpenes, and alkaloids were ingested together with food. They do not possess any nutritional value but seem to be provided with a potential pharmacological activity. Cytochromes and ABC proteins, which evolved over time to detoxify food from vegetable chemical "actives," now seem to limit the action of herbal derivatives. The comprehension of these 2 events may explain the origin of the widespread scepticism of physicians about herbal medicine and suggests that, after correct herbal standardization, use of antagonists of cytochromes and ABC systems will make it possible to recover their pharmacological potential.

Therapeutic potential of curcumin in digestive diseases

Curcumin is a low-molecular-weight hydrophobic polyphenol that is extracted from turmeric, which possesses a wide range of biological properties including anti-inflammatory, anti-oxidant, anti-proliferative and anti-microbial activities. Despite its diverse targets and substantial safety, clinical applications of this molecule for digestive disorders have been largely limited to case series or small clinical trials. The poor bioavailability of curcumin is likely the major hurdle for its more widespread use in humans. However, complexation of curcumin into phytosomes has recently helped to bypass this problem, as it has been demonstrated that this new lecithin formulation enables increased absorption to a level 29-fold higher than that of traditional curcuminoid products. This allows us to achieve much greater tissue substance delivery using significantly lower doses of curcumin than have been used in past clinical studies. As curcumin has already been shown to provide good therapeutic results in some small studies of both inflammatory and neoplastic bowel disorders, it is reasonable to anticipate an even greater efficacy with the advent of this new technology, which remarkably improves its bioavailability. These features are very promising and may represent a novel and effective therapeutic approach to both functional and organic digestive diseases.

Antioxidant and hepatoprotective effects of silymarin phytosomes compared to milk thistle extract in CCl4 induced hepatotoxicity in rats

Milk thistle extract is a well-known hepatoprotectant with low bioavailability (20-50%). The objective of the present study is to prepare and characterize silymarin phytosomes and to test the hepatoprotective effect of the phytosomes in CCl4 induced liver injury in rats compared to milk thistle extract. Phytosomes were prepared using lecithin from soybeans and from egg yolk. The prepared phytosomes were examined using scanning electron microscopy, transmission electron microscopy, differential scanning calorimetry, Fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy (H(1)NMR). The loading efficiency was >85% in all phytosomal formulations. Formula P2 (with the molar ratio of soybean lecithin to silybin 1:1) and P4 (with the molar ratio of egg-yolk lecithin to silybin 0.25:1) exhibited significantly (p < 0.05) faster release than milk thistle extract. The in vivo study revealed that phytosomes significantly (p < 0.05) decreased glutamic pyruvic transaminase and super oxide dismutase activities compared to milk thistle extract.

Formulation and in vitro absorption analysis of Rhizoma paridis steroidal saponins

Rhizoma paridis steroidal saponins (RPS) have been prepared and identified as the active compounds for antitumor activity in our previous study. However, the low oral bioavailability of the steroidal saponins restricted its using. In the present research, solid dispersion (SD) and phytosome (PHY) formulation of RPS were prepared, and the physicochemical parameters as well as the intestinal absorption in rat everted gut sac model were investigated. Seven agents were selected as the carriers of SD, and poloxamer 407 (P 407) was the most suitable one. SD reduced the particle size of saponins in the water solution, enhanced the solubility of the saponins by about 3.5 folds, and significantly improved the absorption transport of saponins from 48 to 104 μg in everted gut sac of the rat system. PHY significantly enhanced the hydrophilic of saponins but showed little effect on the absorption in small intestine. Jejunum and ileum part absorbed more absolute contents of total saponins than duodenum parts. Six saponins, the main contents of RPS, used as the index of comparing the three forms, were also further investigated in the physico-chemical properties and the absorption tests. n-Octanol/water partition coefficients of the six saponins ordered in RPS, SD and PHY were Chonglouoside H>Dioscin>Polyphyllin D>Gracillin>Paris-VII>Formosanin C. All the saponins possessed the higher absorptive characteristics in SD formulation. The absorption rate of diosgenyl saponins in intestine was more than the pennogenyl saponins.

Effect of phospholipid-based formulations of Boswellia serrata extract on the solubility, permeability, and absorption of the individual boswellic acid constituents present

Boswellia serrata gum resin extracts are used widely for the treatment of inflammatory diseases. However, very low concentrations in the plasma and brain were observed for the boswellic acids (1-6, the active constituents of B. serrata). The present study investigated the effect of phospholipids alone and in combination with common co-surfactants (e.g., Tween 80, vitamin E-TPGS, pluronic f127) on the solubility of 1-6 in physiologically relevant media and on the permeability in the Caco-2 cell model. Because of the high lipophilicity of 1-6, the permeability experiments were adapted to physiological conditions using modified fasted state simulated intestinal fluid as apical (donor) medium and 4% bovine serum albumin in the basolateral (receiver) compartment. A formulation composed of extract/phospholipid/pluronic f127 (1:1:1 w/w/w) increased the solubility of 1-6 up to 54 times compared with the nonformulated extract and exhibited the highest mass net flux in the permeability tests. The oral administration of this formulation to rats (240 mg/kg) resulted in 26 and 14 times higher plasma levels for 11-keto-β-boswellic acid (1) and acetyl-11-keto-β-boswellic acid (2), respectively. In the brain, five times higher levels for 2 compared to the nonformulated extract were determined 8 h after oral administration.

Enhanced absorption of boswellic acids by a lecithin delivery form (Phytosome(®)) of Boswellia extract

The anti-inflammatory potential of Boswellia serrata gum resin extracts has been demonstrated in vitro and in animal studies as well as in pilot clinical trials. However, pharmacokinetic studies have evidenced low systemic absorption of boswellic acids (BAs), especially of KBA and AKBA, in rodents and humans. This observation has provided a rationale to improve the formulation of Boswellia extract. We present here the results of a murine comparative bioavailability study of Casperome™, a soy lecithin formulation of standardized B. serrata gum resin extract (BE), and its corresponding non-formulated extract. The concentration of the six major BAs [11-keto-β-boswellic acid (KBA), acetyl-11-keto-β-boswellic acid (AKBA), β-boswellic acid (βBA), acetyl-β-boswellic acid (AβBA), α-boswellic acid (αBA), and acetyl-α-boswellic acid (AαBA)] was evaluated in the plasma and in a series of tissues (brain, muscle, eye, liver and kidney), providing the first data on tissue distribution of BAs. Weight equivalent and equimolar oral administration of Casperome™ provided significantly higher plasma levels (up to 7-fold for KBA, and 3-fold for βBA quantified as area under the plasma concentration time curve, AUC(last)) compared to the non-formulated extract. This was accompanied by remarkably higher tissue levels. Of particular relevance was the marked increase in brain concentration of KBA and AKBA (35-fold) as well as βBA (3-fold) following Casperome™ administration. Notably, up to 17 times higher BA levels were observed in poorly vascularized organs such as the eye. The increased systemic availability of BAs and the improved tissue distribution, qualify Casperome™ for further clinical development to fully exploit the clinical potential of BE.

Advances in nanotechnology-based delivery systems for curcumin

Curcumin (CUR), a bioactive component of turmeric, which is a commonly used spice and nutritional supplement, is isolated from the rhizomes of Curcuma longa Linn. (Zingiberaceae). In recent years, the potential pharmacological actions of CUR in inflammatory disorders, cardiovascular disease, cancer, Alzheimer’s disease and neurological disorders have been shown. However, the clinical application of CUR is severely limited by its main drawbacks such as instability, low solubility, poor bioavailability and rapid metabolism. Multifarious nanotechnology-based delivery approaches have been used to enhance the oral bioavailability, biological activity or tissue-targeting ability of CUR. This article reviews potential novel drug delivery systems for CUR including liposomes, polymeric nanoparticles, solid lipid nanoparticles, micelles, nanogels, nanosuspensions, nanoemulsions, complexes and dendrimer/dimer, which provide promising results for CUR to improve its biological activities.

Comparative absorption of a standardized curcuminoid mixture and its lecithin formulation

The relative absorption of a standardized curcuminoid mixture and its corresponding lecithin formulation (Meriva) was investigated in a randomized, double-blind, crossover human study. Clinically validated dosages were used for both products, and plasma levels of all three major curcuminoids [curcumin (1a), demethoxycurcumin (1b), and bisdemethoxycurcumin (1c)] were evaluated. Total curcuminoid absorption was about 29-fold higher for Meriva than for its corresponding unformulated curcuminoid mixture, but only phase-2 metabolites could be detected, and plasma concentrations were still significantly lower than those required for the inhibition of most anti-inflammatory targets of curcumin. Remarkably, phospholipid formulation increased the absorption of demethoxylated curcuminoids much more than that of curcumin (1a), with significant differences in plasma curcuminoid profile between Meriva and its corresponding unformulated curcuminoid mixture. Thus, the major plasma curcuminoid after administration of Meriva was not curcumin (1a), but demethoxycurcumin (1b), a more potent analogue in many in vitro anti-inflammatory assays. The improved absorption, and possibly also a better plasma curcuminoid profile, might underlie the clinical efficacy of Meriva at doses significantly lower than unformulated curcuminoid mixtures.