One-step preparation of chitosan/sodium dodecyl sulfate-stabilized oil-in-water emulsion of Zingiber cassumunar Roxb. oil extract

Enzymatic grafting of 5-O-succinyl erythorbyl myristate onto chitosan to improve its emulsifying properties

Chitosan (CS) is a versatile polysaccharide with numerous inherent biological activity, while the lack of amphiphilicity limits its application in emulsion-based systems. In this study, erythorbyl myristate (EM) with interfacial activity was chemically modified to 5-O-succinyl EM (EMS) and grafted onto CS to improve the emulsifying properties. The grafting reaction was conducted by the catalysis of protease, with the progress of the reaction monitored by HPLC analysis and UV absorbance measurement. Structural identification by FTIR and two-dimensional 1H13C HSQC NMR spectroscopy confirmed the protease-catalyzed grafting of EMS onto CS. The grafting ratio of synthesized EMS-grafted CS (EMS-g-CS) was determined to be 13.30 ± 0.60 % according to the UV absorbance measurement and 1H NMR analysis. Evaluation of the emulsifying properties of EMS-g-CS revealed that the grafting reaction significantly enhanced both emulsifying activity and emulsion stability, compared to the CS, EM, and their mixture. The oil-in-water emulsion stabilized with 1 % (w/v) EMS-g-CS exhibited emulsifying activity index of 6.03 ± 0.13 m2/g with homogeneous and stable droplet size distribution and exhibited a turbiscan stability index of 2.05 after 3 days. These findings suggested that EMS-g-CS synthesized via the chemoenzymatic process can be a promising polymeric emulsifier for utilization in emulsion-based systems.

Imaging the distribution of DMPBD and terpinen-4-ol inclusion complexes with 2-hydroxypropyl-β-cyclodextrin by using TOF-SIMS

The distribution of terpinen-4-ol (TP4ol) and DMPBD inclusion complexes with 2-hydroxypropyl-β-cyclodextrin (HPbCD) in human skin has been investigated using the TOF-SIMS technique. TP4ol and DMPBD have been found to be major components of Zingiber cassumunar Roxb. (Plai) oil extracted by steam distillation. The results mainly show accumulation of TP4ol and DMPBD inclusion complexes with HPbCD in the epidermis and dermis whereas these two compounds without cyclodextrin cannot penetrate into the epidermis. This approach can be expanded for investigation of anti-inflammatory action and relief of muscle pain.

Study of vitamin E microencapsulation and controlled release from chitosan/sodium lauryl ether sulfate microcapsules

Potential benefit of microencapsulation is its ability to deliver and protect incorporated ingredients such as vitamin E. Microcapsule wall properties can be changed by adding of coss-linking agents that are usually considered toxic for application. The microcapsules were prepared by a spray-drying technique using coacervation method, by depositing the coacervate formed in the mixture of chitosan and sodium lauryl ether sulfate to the oil/water interface. All obtained microcapsules suspensions had slightly lower mean diameter compared to the starting emulsion (6.85 ± 0.213 μm), which shows their good stability during the drying process. The choice and absence of cross-linking agents had influence on kinetics of vitamin E release. Encapsulation efficiency of microcapsules without cross-linking agent was 73.17 ± 0.64 %. This study avoided the use of aldehydes as cross-linking agents and found that chitosan/SLES complex can be used as wall material for the microencapsulation of hydrophobic active molecules in cosmetic industry.

Chitosan/carboxymethylcellulose-stabilized poly(lactide-co-glycolide) particles as bio-based drug delivery carriers

Poly(lactide-co-glycolide) (PLGA) colloidal particles stabilized by complexes of two oppositely charged polysaccharides, chitosan (cationic, CS) and sodium carboxymethylcellulose (anionic, NaCMC), were fabricated. Dichloromethane containing dissolved PLGA was first emulsified in an aqueous phase containing mixtures of CS and NaCMC. Evaporation of dichloromethane from the resulting emulsion led to CS/NaCMC-covered-PLGA particles. CS and NaCMC contents affected the short-term stability of PLGA particles and also their intrinsic characteristics. The particles displayed pH-dependent characteristic. Zeta potential varied from +54 to -50 mV when pH was varied from 3 to 10. CS/NaCMC-covered-PLGA particles showed colloidal stability, over a wider pH range as compared to CS-covered-PLGA particles. Curcumin, a model hydrophobic drug, was encapsulated into the particles up to 10 wt% of PLGA. The CS/NaCMC-covered-PLGA particles loaded with curcumin showed delayed release in mildly acidic conditions and faster release in neutral and basic conditions. Cytotoxicity experiments were carried out with human colorectal carcinoma cells.

In vitro evaluation of intravesical mucoadhesive self-emulsifying drug delivery systems

Intravesical mucoadhesive self-emulsifying drug delivery system (SEDDS) have been developed via synthesis and incorporation of S-protected chitosan CS-MNA into SEDDS. N-acetyl cysteine-6-mercaptonicotinamide (NAC-6-MNA) was synthetized via disulphide exchange reaction between N-acetyl cysteine and 6-mercaptonicotinamide dimer. NAC-6-MNA was attached to chitosan (CS) via carbodiimide mediated amide bond formation. The S-protected chitosan (CS-MNA) and chitosan (CS) were complexed with sodium dodecyl sulfate (CS-SDS and CS-MNA-SDS) and incorporated in SEDDS at a concentration of 1% (m/m). SEDDS, SEDDS-CS-SDS and SEDDS-CS-MNA-SDS were characterized regarding size and zeta potential. 6-MNA release from SEDDS-CS-MNA-SDS in presence of glutathione was evaluated. Mucoadhesive properties of these novel formulations were assessed via rheology measurements and residence time evaluation on porcine bladder. Cytotoxicity of formulations was determined on porcine bladder. S-protected chitosan displayed 465.42 ± 75.64 µmol of NAC-6-MNA per gram of polymer. SEDDS and SEDDS-CS-SDS and SEDDS-CS-MNA-SDS displayed a size of 22.5 ± 0.9, 37.4 ± 0.1 and 98.5 ± 5.7 nm at a concentration of 20% (m/v) in simulated urine pH 6.2, and a zeta potential of -5.1 ± 0.2, -1.6 ± 0.1 and -1.4 ± 0.2 mV at a concentration of 1% (m/v) in water at pH 6, respectively. 80% of MNA was released from SEDDS-CS-MNA-SDS in presence of glutathione. Viscosity of SEDDS-CS-SDS/mucus and SEDDS-CS-MNA-SDS/mucus was 6- and 18-fold higher than SEDDS/mucus after 90 min incubation. 2.6%, 5.8% and 14% of SEDDS, SEDDS-CS-SDS and SEDDS-CS-MNA-SDS remained on bladder mucosa within 120 min, respectively. No pronounced bladder cytotoxicity was observed in presence of 0.5% (m/v) formulations. According to these results, SEDDS-CS-MNA-SDS might be a promising carrier for intravesical drug administration.

Stability and antimicrobial activity of eucalyptus essential oil emulsions

We evaluated various formulations of oil-in-water emulsions prepared from eucalyptus essential oil, for their stability and antimicrobial activity against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. These formulations were developed using a response surface experimental design and analyzed with Design-Expert® 10 software. The emulsions were prepared in a colloid mill, and emulsion characterization was performed using the zeta ( ζ)-potential, droplet size distribution, and phase separation. The antimicrobial effects were assessed by death kinetics. The droplet size and ζ-potential of the 16 emulsions ranged from 1.071 to 1.865 µm (based on Feret's diameter) and -34.8 to -24 mV, respectively. Three formulations (14, 15, and 16) demonstrated the highest stability parameters (no phase separation) during the 28 days of evaluation. Eucalyptus essential oil emulsions exhibited antimicrobial activity against E. coli, S. aureus, and P. aeruginosa in less than 1 min.

Topical Niosome Gel of Zingiber cassumunar Roxb. Extract for Anti-inflammatory Activity Enhanced Skin Permeation and Stability of Compound D

An extract of Zingiber cassumunar Roxb. (ZC) was encapsulated in niosomes of which a topical gel was formed. (E)-4-(3',4'-dimethoxyphenyl)but-3-en-1-ol or compound D detected by a gradient HPLC was employed as the marker and its degradation determined to follow zero-order kinetics. Niosomes significantly retarded thermal-accelerated decomposition of compound D in the gel (p < 0.05) but did not change the activation energy of compound D. Niosomes enhanced in vitro permeation rate of compound D from the gel. Topical applications of ZC noisome gel gave a faster change in tail flick latency than piroxicam gel and hydrocortisone cream (p < 0.05) while there were insignificant differences in anti-inflammatory activity up to 6 h using croton oil-induced ear edema model in mice (p > 0.05). Thus, encapsulation of ZC extract in niosomes enhanced chemical stability and skin permeation with comparable topical anti-inflammatory effects to steroid and NSAID.

Herbal infusions of black seed and wheat germ oil: Their chemical profiles, in vitro bio-investigations and effective formulations as Phyto-Nanoemulsions

The reported studies related to black seed oil (BSO) and wheat germ oil (WGO) have illustrated that they have a wide range of biological activities. Therefore, enhancing the amount of bio-active compounds that caused higher cell based anti-oxidative effect as well as cell proliferation, etc. in seed oils, infusion of crude plant material has been gained importance as a traditional technique. Herein, we accomplished the infusion of Calendula flowers that also contains many phyto-constituents into BSO and WGO. After the infusion of oils, the change of phytochemical amount was investigated and evaluated according to the oils by chromatography, radical scavenging activity. Subsequently, for investigating the biological impact upon live cells, cytotoxicity, cell-based antioxidant capacity, wound healing and radioprotective activity were tested with monkey kidney fibroblast like cells (Vero) and HaCaT keratinocytes. In vitro cell based experiments (wound healing and radioprotective activity) confirmed that Calendula infused BSO and WGO have greater bio-activity when compared to those plain forms. The herbal oils prepared with an effective extraction technique were incorporated into nanoemulsion systems which will be then called as 'Phyto-Nanoemulsion'. After herbal oil biomolecules were encapsulated into nanoemulsion based delivery systems, the designed formulations were investigated in terms of biological activities. In conclusion, these preparations could be a good candidate as a part of dermal cosmetic products or food supplements which have the therapeutic efficiency, especially after radio- or chemotherapy.

Co-assembly in chitosan-surfactant mixtures: thermodynamics, structures, interfacial properties and applications

In this review, different aspects characterizing chitosan-surfactant mixtures are summarized and compared. Chitosan is a bioderived cationic polysaccharide that finds wide-ranged applications in various field, e.g., medical or food industry, in which synergistic effects with surfactant can play a fundamental role. In particular, the behavior of chitosan interacting with strong and weak anionic, nonionic as well as cationic surfactants is reviewed. We put a focus on oppositely charged systems, as they exhibit the most interesting features. In that context, we discuss the thermodynamic description of the interaction and in particular the structural changes as they occur as a function of the mixed systems and external parameters. Moreover, peculiar properties of chitosan coated phospholipid vesicles are summarized. Finally, their co-assembly at interfaces is briefly reviewed. Despite the behavior of the mentioned systems might strongly differ, resulting in a high variety of properties, few general rules can be pointed out which improve the understanding of such complex systems.