Hydrolysis and Transport Characteristics of Phospholipid Complex of Alkyl Gallates: Potential Sustained Release of Alkyl Gallate and Gallic Acid

Phospholipid complexes of alkyl gallates (A-GAs) including ethyl gallate (EG), propyl gallate (PG), and butyl gallate (BG) were successfully prepared by the thin film dispersion method. HPLC-UV analysis in an everted rat gut sac model indicated that A-GAs can be liberated from phospholipid complexes, which were further hydrolyzed by intestinal lipase to generate free gallic acid (GA). Both A-GAs and GA are able to cross the membrane, and the hydrolysis rate of A-GAs and the transport rate of GA are positively correlated with the alkyl chain length. Especially, compared with the corresponding physical mixtures, the phospholipid complexes exhibit slower sustained-release of A-GAs and GA. Therefore, the formation of phospholipid complexes is an effective approach to prolong the residence time in vivo and additionally enhance the bioactivities of A-GAs and GA. More importantly, through regulating the carbon skeleton lengths, controlled-release of alkyl gallates and gallic acid from phospholipid complexes will be achieved.

Self-assembled fisetin-phospholipid complex: Fisetin-integrated phytosomes for effective delivery to breast cancer

Nowadays, fisetin (FIS) is extensively studied as potent anticancer surrogate with a multitarget actions against various types of cancers including breast cancer. However, its poor aqueous solubility handicapped its clinical utility. The current work endeavored, for the first time, to develop FIS phytosomes (FIS-PHY) for improving its physicochemical properties and subsequently its anticancer activity. Optimization of FIS- phytosomes involved different preparation techniques (Thin film hydration and ethanol injection) and different FIS: phospholipid molar ratios (1:1, 1:2, and 1:3). Complex formation was confirmed by complexation efficiency, infrared spectroscopy (IR), solubility studies and transmission electron microscope. The optimized FIS-PHY of 1:1 M ratio (PHY1) exhibited a nanometric particle size of 233.01 ± 9.46 nm with homogenous distribution (PDI = 0.27), negative zeta potential of - 29.41 mV, 100% complexation efficiency and controlled drug release over 24 h. In-vitro cytotoxicity study showed 2.5-fold decrease in IC50 of PHY1 compared with free FIS. Also, pharmacodynamic studies confirmed the promoted cytotoxicity of PHY1 against breast cancer through modulating TGF-β1/MMP-9 molecular pathways of tumorigenesis. Overall, overcoming FIS drawbacks were successfully achieved through development of innovative biocompatible phytosomal system.

Phytosomes as an Emerging Nanotechnology Platform for the Topical Delivery of Bioactive Phytochemicals

The emergence of phytosome nanotechnology has a potential impact in the field of drug delivery and could revolutionize the current state of topical bioactive phytochemicals delivery. The main challenge facing the translation of the therapeutic activity of phytochemicals to a clinical setting is the extremely low absorption rate and poor penetration across biological barriers (i.e., the skin). Phytosomes as lipid-based nanocarriers play a crucial function in the enhancement of pharmacokinetic and pharmacodynamic properties of herbal-originated polyphenolic compounds, and make this nanotechnology a promising tool for the development of new topical formulations. The implementation of this nanosized delivery system could enhance the penetration of phytochemicals across biological barriers due to their unique physiochemical characteristics, improving their bioavailability. In this review, we provide an outlook on the current knowledge of the biological barriers of phytoconstituents topical applications. The great potential of the emerging nanotechnology in the delivery of bioactive phytochemicals is reviewed, with particular focus on phytosomes as an innovative lipid-based nanocarrier. Additionally, we compared phytosomes with liposomes as the gold standard of lipid-based nanocarriers for the topical delivery of phytochemicals. Finally, the advantages of phytosomes in topical applications are discussed.

Novel rhein integrate transphytosomes as non-invasive local therapy for osteoarthritis to ameliorate cartilage deterioration in MIA-arthritic rats

Rhein (RH), a natural chondroprotective agent, suffers from poor systemic availability (20-25%) after oral administration concomitant to side effects on the gastrointestinal tract and liver. We present a new approach for non-invasive local targeted delivery of rhein to ameliorate cartilage deterioration employing cartilage-homing phospholipids nanocarriers. This is the first work to elaborate RH loaded transphytosome (RH-T-PHY) as novel nanovesicular systems for transdermal drug delivery based on an advantageous hybrid between phytosomes and transfersomes or bilosomes. Here, we developed transphytosomes through incorporating various edge activators (EAs) such as Tween 80, Span 80 and sodium deoxycholate into the lipid bilayer of RH phytosomes to affix the flexibility. RH-T-PHY with high flexibility and entrapment efficacy showed the highest significant skin permeation compared to conventional phytosomes. Additionally, RH-T-PHY have a magnificent potential in maintaining high chondroprotective activity as demonstrated by enhanced repair, regeneration of chondrocytes and GAG formation in MIA-induced osteoarthritis (OA) rat model. Besides, histological examination of vital organs revealed the formulation safety. Confocal laser microscopy images revealed the highest drug availability in the articular cartilage of RH-T-PHY treated group. Conclusively, novel RH-T-PHY can serve as a promising alternative means for delivery of chondroprotective drugs for effective non-invasive local therapy of OA.

Rheological behavior study and its significance in the assessment of application properties and physical stability of phytosome loaded hydrogels

Phytosomes are amphiphilic molecular complexes of substances of plant origin and phospholipids that are considered as active ingredients of dermopharmaceutical and cosmetic formulations of potentially improved efficiency. The study aim was the formulation of carbomer hydrogels with commercially available phytosomes of escin (Escin ß-Sitosterol Phytosome®) (EP) and 18-ß glycyrrhetinic acid (18-ß Glycyrrhetinic Acid Phytosome®) (GP) and evaluation of their application properties and real-time physical stability. Phytosomes incorporation did not significantly affect pH of the hydrogels, which was acceptable for cutaneous application. However, these hydrogels had significantly different organoleptic properties (opaque and softer consistency) compared to the hydrogel without active substance (C) and the hydrogels with pure active substances (E and G) used for comparison. The values of maximum and minimum apparent viscosity and yield stress were significantly lower in phytosome-loaded hydrogels. The results of oscillatory rheological analysis indicated that viscous character prevails in EP and GP hydrogels (elastic modulus (G')˂viscous modulus (G")), while in hydrogels C, E and G elastic properties were more pronounced (G'˃G"). Escin phytosome had greater influence on carbomer gel network strength. Phytosome-loaded hydrogels were physically stable during 24 months of storage under ambient conditions, although the rheological analysis also indicated a potential risk of sedimentation.

Novel rhein-phospholipid complex targeting skin diseases: development, in vitro, ex vivo, and in vivo studies

Rhein (RH), an anthraquinone derivative, has proven to be a promising molecule for treating several skin disorders thanks to its pleiotropic pharmacological activities like antimicrobial, antifungal, antioxidant, and anticancer. However, RH's low water and oil solubility and poor skin permeability halted its topical delivery. This is the first work to investigate the expediency of tailoring a rhein-phospholipid complex (RH-PLC) to improve RH challenging physicochemical and skin permeability properties. The phospholipid complex was prepared by employing different methods and different RH/PL molar ratios. RH-PLC was successfully developed at a stoichiometric ratio of 1:1 using a novel pH-dependent method where at a certain pH, it exhibits the highest complexation efficiency (95%). RH-PLC formation was confirmed using FTIR, DSC, and XRPD analysis. RH-PLC showed a significant increase in water and n-octanol solubility. RH-PLC was self-assembled upon dispersion into water forming nano-sized particles (196.6 ± 1.6 nm) with high negatively charged surface (- 29.7 ± 2.45 mV). RH-PLC exhibited a significant 3.3- and 2.46-fold increase in ex vivo and in vivo skin permeability when compared with RH suspension, respectively. Confocal microscopy study confirmed the ability of RH-PLC to penetrate deeply into rat skin. Besides, skin irritation test on healthy rats indicated compatibility and safety of RH-PLC. Conclusively, phospholipid complex might be a suitable approach to improve permeability of RH and other promising abandoned poor-permeable drugs. The proposed RH-PLC is expected to be a major progressive step toward the development of a topical RH formulation. Graphical abstract.

Topical hydrogels with escin β-sitosterol phytosome and escin: Formulation development and in vivo assessment of antihyperalgesic activity

The physicochemical properties, stability, in vivo antihyperalgesic activity, and skin irritation potential of the carbomer hydrogels with the new chemical entity escin β-sitosterol (ES) phytosome were characterized and compared with those containing escin. Physicochemical characterization of the hydrogels (performed 48 hr after preparation) included organoleptic examination, pH measurement, light microscopy, differential scanning calorimetry analysis and rheological tests. The obtained results showed that increasing concentration of the active substances within 1-5% affected the appearance (color and transparency) of the hydrogels, their pH, consistency, and rheological behavior. Unlike acidic escin, which was dissolved in the liquid phase of the pseudoplastic hydrogels E1-E5 and reduced their maximal apparent viscosity (η_max ), minimal apparent viscosity (η_min ), and hysteresis area (H) in comparison to the plain carbomer hydrogel, amphiphilic ES-enhanced η_max , η_min , and thixotropy of the hydrogels ES1-ES5, which is favorable for prolonged retention at skin surface. Evaluation of in-use stability of the hydrogels showed that organoleptic characteristics, flow behavior, and pH values could be preserved for 3 months under ambient conditions. The rat ear test results suggested that the hydrogels are safe to be used on human skin. Both escin and ES-loaded hydrogels exerted significant, concentration-dependent antihyperalgesic effect in inflammatory pain model in rats. ES-loaded hydrogels were significantly more effective than those loaded with escin. This is a first report on the antihyperalgesic effect of topically applied escin as well as ES in a model of inflammatory pain.