Long-term release of chlorhexidine from dental adhesive resin system using human serum albumin nanoparticles

A functional dental adhesive resin system with antimicrobial properties was developed using human serum albumin (HSA) nanoparticles as the drug delivery carrier. HSA nanoparticles loaded with chlorhexidine (CHX) diacetate, a model antimicrobial drug, were prepared using a desolvation technique. The resulting CHX-loaded HSA nanoparticles were incorporated into a commercial methyl methacrylate (MMA)-based resin. The size of the nanoparticles ranged 50–300 nm, and the nanoparticles were dispersed homogeneously in the resin matrix. The CHX-loaded HSA nanoparticles showed an early release burst of ~20 % of the total CHX by day 5, followed by the sustained release of the remaining CHX over the next 20 days. In contrast, the resin matrix containing the HSA nanoparticles showed a sustained release of CHX without an early release burst in a 4-week immersion study. In the agar diffusion test, the resin matrix incorporating the CHX-loaded HAS nanoparticles showed a larger growth inhibition zone against Streptococcus mutans than the resin matrix alone, indicating that this delivery platform potently imparts antibacterial activity to the resins. These results also suggest that CHX, which inhibits the growth of oral bacteria, can be incorporated efficiently into the MMA-based resin matrix using HSA nanoparticles.     

Studies of reaction variables for lipase-catalyzed production of alpha-linolenic acid enriched structured lipid and oxidative stability with antioxidants

Alpha-linolenic acid (ALA) enriched structured lipid (SL) was produced by lipase-catalyzed interesterification from perilla oil (PO) and corn oil (CO). The effects of different reaction conditions (substrate molar ratio [PO/CO 1:1 to 1:3], reaction time [0 to 24 h], and reaction temperature [55 to 65 °C]) were studied. Lipozyme RM IM from Rhizomucor miehei was used as biocatalyst. We obtained 32.39% of ALA in SL obtained under the optimized conditions (molar ratio-1:1 [PO:CO], temperature-60 °C, reaction time-15 h). In SL, the major triacylglycerol (TAG) species (linolenoyl-linolenoyl-linolenoyl glycerol [LnLnLn], linolenoyl-linolenoyl-linoleoyl glycerol [LnLnL]) mainly from PO and linoleoyl-linoleoyl-oleoyl glycerol (LLO), linoleoyl-oleoyl-oleoyl glycerol (LOO), palmitoyl-linoleoyl-oleoyl glycerol (PLO) from CO decreased while linolenoyl-linolenoyl-oleoyl glycerol (LnLnO) (18.41%), trilinolein (LLL) (9.06%), LLO (16.66%), palmitoyl-linoleoyl-linoleoyl glycerol (PLL) (9.69%) were increased compared to that of physical blend. Total tocopherol content (28.01 mg/100 g), saponification value (SV) (192.2), and iodine value (IV) (161.9) were obtained. Furthermore, oxidative stability of the SL was also investigated by addition of 3 different antioxidants (each 200 ppm of rosemary extract [SL-ROS], BHT [SL-BHT], catechin [SL-CAT]) was added into SL and stored in 60 °C oven for 30 d. 2-Thiobabituric acid-reactive substances (TBARS) value was 0.16 mg/kg in SL-CAT and 0.18 mg/kg in SL-ROS as compared with 0.22 mg/kg in control (SL) after oxidation. The lowest peroxide value (POV, 200.9 meq/kg) and longest induction time (29.88 h) was also observed in SL-CAT.     

Crystallization,Physicochemical Properties,and Oxidative Stability of the Interesterified Hard Fat from Rice Bran Oil,Fully Hydrogenated Soybean Oil,and Coconut Oil through Lipase-Catalyzed Reaction

Interesterified hard fat (IEHF) was produced from fully hydrogenated soybean oil (FHSBO) and rice bran oil (RBO) with different molar ratio (RBO/FHSBO = 1:1, 1:2, and 1:3). For interesterification, Lipozyme TL IM (10% of total substrates) was used as a biocatalyst. Further, coconut oil (CO; 40 wt.% on total weight of RBO and FHSBO) was also added in all reactants for providing medium chain fatty acid. After interesterification, the obtained IEHF and physical blend (before interesterification) with same molar ratio were carried out for comparing the physical properties, (i.e., solid fat content, melting and crystallization behavior, and polymorphic forms). From DSC results at 25 °C, solid fat content of the IEHF with different molar ratio (RBO/FHSBO = 1:1, 1:2, and 1:3) were 33.9%, 58.8%, and 72.1%, respectively, whereas physical blends at same molar ratio showed 66.2%, 71.6%, and 74.8%. Besides, short spacing β crystal polymorphic form was observed in the physical blend while only β′ crystal form was observed in IEHF, in which β′ polymorphic form is a desirable for the production of shortenings and margarines. In Rancimat test for oxidative stability, IEHF showed significantly lower induction time than the physical blend. When the catechin (200, 400, and 800 ppm) was added to the IEHF, induction time was significantly increased to 21.4, 34.1, and 44.3 h, respectively. In this study, IEHF from this study may have a potential functionality for the shortenings and margarines.     

Anti-inflammatory drug releasing absorbable surgical sutures using poly(lactic-co-glycolic acid) particle carriers

The goal of the current study was to develop an absorbable surgical suture incorporating poly(lactic-co-glycolic acid) (PLGA) particles loaded with dexamethasone (DEX) as an anti-inflammatory drug. DEX-loaded PLGA (DEX/PLGA) particles, prepared using a water-in-oil emulsion method, were electrostatically immobilized onto the surface of absorbable sutures. The surfaces of these DEX/PLGA particles were coated with positively charged polyethyleneimine (PEI) molecules, which imparted a net positive surface charge. These modified PEI-coated DEX/PLGA (PEI/DEX/PLGA) particles were then immobilized on negatively charged absorbable suture surfaces by electrostatic attraction. The results showed that DEX was efficiently loaded into PLGA particles and that the surfaces of DEX/PLGA particles were successfully coated with PEI. PEI/DEX/PLGA particles were well dispersed and immobilized onto suture surfaces. In addition, PEI/DEX/PLGA particles remained adherent to suture surfaces in vitro and demonstrated sustained DEX release in phosphate-buffered saline (pH 7.4) at 37 °C for up to 28 days under static conditions. The tensile strength and elongation at break of PEI/DEX/PLGA particle-treated sutures were almost the same as that of non-treated control sutures. Findings of this study show that various therapeutic drugs could be efficiently incorporated into absorbable sutures using biodegradable polymeric particles, and suggest that the devised absorbable, drug-eluting, sutures offer a promising basis for a novel absorbable surgical suture system.     

Antioxidative activities of mao feng tea (Camellia spp.) and kamtae (Ecklonia cava) extracts and their effects on structured lipid from corn and perilla oil

In the study, solvent extracts of kamtae (Ecklonia cava) and mao feng tea (Camillia sinensis) were used for obtaining different fractions of organic solvents (diethyl ether, butanol, and ethyl acetate) and the extracted fractions were studied for their antioxidative activities. The total phenolic contents of the mao feng tea ranged from 1.44 to 5.97 mM GAE/g while kamtae ranged from 1.13 to 4.41 mM GAE/g, respectively. Among them, ethyl acetate fraction showed the highest content of phenolic compounds, resulting in Trolox equivalent antioxidant capacity (TEAC) values as 1,554.54 (from mao feng tea) and 1,097.63 mM Trolox E/g (from kamtae). Also, ethyl acetate fractions from mao feng tea showed the highest DPPH (89.27 RSC%), superoxide anion scavenging activity (46.58%), and ferric reducing antioxidant power (FRAP) (242.2 mg GAE/g) while ethyl acetate fractions from kamtae (K-EA) showed the highest DPPH (82.23 RSC%), superoxide anion scavenging activity (28.82%), and FRAP (162.43 mg GAE/g) among the obtained fractions.     

Emulsifying Properties of Lecithin Containing Different Fatty Acids Obtained by Immobilized Lecitase Ultra-Catalyzed Reaction

Lecitase Ultra and 6 triacylglycerol lipases (lipases PS, M, AH, AY, R, and AK) were immobilized on Amberlite XAD 7HP and used to catalyze the acidolysis reaction between lecithin and capric acid (C10:0) for comparison. The highest molar incorporation value (51.0 mol%) was observed for the immobilized Lecitase Ultra. Further, immobilized Lecitase Ultra was selected for catalyzing acidolysis between lecithin and fatty acids with different chain lengths (C6:0, C8:0, C10:0, C12:0, and C14:0). After reaction, free fatty acids were removed by SPE and the resultant was called modified lecithin fraction 1 (MLF1). The highest molar incorporation value was obtained for C10:0 (51.0 mol%) at 45 °C with a mole ratio of 10/1 (C10:0/lecithin) for 72 h. After removal of lysophosphatidylcholine by solid-phase extraction from MLF1, the resultant modified lecithin fraction 2 (MLF2) was used to prepare an oil-in-water emulsion. All emulsions prepared with MLF2 exhibited significantly higher emulsion stability (ES) values (16.2–17.7) and smaller particle sizes (d ₃₂ 0.40–0.49 μm, d ₄₃ 0.75–1.01 μm) than the emulsion prepared with unmodified lecithin (ES 14.1, d ₃₂ 0.76 μm, d ₄₃, 1.26 μm) (P < 0.05). Furthermore, less clarification and droplet aggregation were observed in emulsions prepared with MLF2 than in lecithin-based emulsions. Overall, the MLF2s showed better emulsifying properties than lecithin.     

Study of Structured Lipid-Based Oil-in-Water Emulsion Prepared with Sophorolipid and its Oxidative Stability

In this study, the stability of oil-in-water (O/W) emulsions prepared with structured lipid (SL) were evaluated in which the SL was produced through lipase-catalyzed interesterification between soybean oil and rice bran oil. After interesterification, the major TAG species in the SL were PLP (22.5 %), PLL/OOLn (21.8 %), LPL (16.1 %), and LLS/PLO (16.1 %), and the total amount of tocopherol and tocotrienol was 20.9 mg/100 g of SL. Sophorolipid was used as an emulsifier for preparing SL-based O/W emulsions, and the effect of pH (pH 5.8, 7 and 7.2) on stability was studied by analyzing the fat globule size. From the results, SL-based O/W emulsions showed similar stabilities to those prepared with Tween 20 at the neutral environment. In the oxidation study, any antioxidant addition of propyl gallate (PG), ascorbic acid 6-palmitate (AP) or quercetin hydrate (Que) distinctively prevented peroxide formation on the SL-based O/W emulsion throughout the 23 days of storage while AP was less effective to lower TBARS values than PG and Que.