Phase behavior characterization of propylene glycol,white petrolatum,surfactant ointments

Abstract

Ointment vehicles consisting of moderate amounts of propylene glycol (5–10%) and large amounts of white petrolatum (greater than 80%) were investigated by determining the ternary phase behavior between these two components and each of five surfactants exhibiting a range of physical properties. The commercial anionic surfactant Pationic SSL performed better as an emulsifier for propylene glycol and white petrolatum than did Lexamul 515, Lexamul AR, Arlacel 20, or Grilloten ZT 40. From this study a formulation consisting of 7% propylene glycol, 90% petrolatum, and 3% Pationic SSL was considered to be an optimized propylene glycol/white petrolatum ointment base.     

Physical characterization and cellular uptake of propylene glycol liposomes in vitro

In order to facilitate the intracellular delivery of therapeutic agents, a new type of liposomes–propylene glycol liposomes (PGL) were prepared, and their cell translocation capability in vitro was examined. PGL was composed of hydrogenated egg yolk lecithin, cholesterol, Tween 80 and propylene glycol. With curcumin as a model drug, characterization of loaded PGL were measured including surface morphology, particle size, elasticity, encapsulation efficiency of curcumin and physical stability. Using curcumin-loaded conventional liposomes as the control, the cell uptake capacity of loaded PGL was evaluated by detection the concentration of curcumin in cytoplasm. Compared with conventional liposomes, PGL exhibited such advantages as high encapsulation efficiency (92.74% ± 3.44%), small particle size (182.4?±?89.2?nm), high deformability (Elasticity index?=?48.6) and high stability both at normal temperature (about 25°C) and low temperature at 4°C. From cell experiment in vitro, PGL exhibited the highest uptake of curcumin compared with that of conventional liposomes and free curcumin solution. Little toxic effect on cellular viability was observed by methyl tetrazolium assay. In conclusion, PGL might be developed as a promising intracellular delivery carrier for therapeutic agents.     

Physical characterization and cellular uptake of propylene glycol liposomes in vitro

In order to facilitate the intracellular delivery of therapeutic agents, a new type of liposomes-propylene glycol liposomes (PGL) were prepared, and their cell translocation capability in vitro was examined. PGL was composed of hydrogenated egg yolk lecithin, cholesterol, Tween 80 and propylene glycol. With curcumin as a model drug, characterization of loaded PGL were measured including surface morphology, particle size, elasticity, encapsulation efficiency of curcumin and physical stability. Using curcumin-loaded conventional liposomes as the control, the cell uptake capacity of loaded PGL was evaluated by detection the concentration of curcumin in cytoplasm. Compared with conventional liposomes, PGL exhibited such advantages as high encapsulation efficiency (92.74% ± 3.44%), small particle size (182.4?±?89.2?nm), high deformability (Elasticity index?=?48.6) and high stability both at normal temperature (about 25°C) and low temperature at 4°C. From cell experiment in vitro, PGL exhibited the highest uptake of curcumin compared with that of conventional liposomes and free curcumin solution. Little toxic effect on cellular viability was observed by methyl tetrazolium assay. In conclusion, PGL might be developed as a promising intracellular delivery carrier for therapeutic agents.     

Low temperature specific heat of propylene glycol

The specific heat of propylene glycol has been measured at temperatures from 0.1 K to 6 K. The magnitude and the temperature dependence of the specific heat are similar to that found in other fragile glasses.     

Rheological characterization of petrolatum using a controlled stress rheometer

The current study focuses on characterizing the rheological characteristics of different petrolatum grades using a controlled stress rheometer. Both steady-state flow and dynamic oscillatory tests were conducted on the petrolatums. The thermorheological scans were found to be the most informative and reproducible for this study. Significant differences in the structure were observed between the petrolatum grades. The structural differences were found to be most significant in the temperature range 25-35°C. The findings from this study will help in identifying the critical parameters (for e.g., temperature, mixing) during the processing and handling of such materials, which can have a direct impact on the product rheology and performance.     

Conjugates of unsaturated fatty acids with propylene glycol as potentially less-irritant skin penetration enhancers

Fatty acids (FA) are well known as efficient enhancers for transdermal delivery of drugs; however, their frequent dermal toxicity limits their regular use. In order to utilize the fatty acid as a safe enhancer devoid of its irritant effect, we have synthesized and evaluated a series of fatty acids conjugated to propylene glycol (FA-PG). Each one of the conjugates was prepared as a mono- or di- acyl ester derivative. The effects of the synthetic enhancers on the porcine skin permeability were evaluated in a diffusion cell system using lidocaine as the model drug. In addition, in vivo examinations in rabbits were preformed for skin toxicological evaluation. The results indicate that among the FA-PG conjugates, oleic acid (C18:1(n-9))-PG, linoleic acid (C18:2(n-6))-PG and alpha-linolenic acid (C18:3(n-3))-PG, mono- or di-esters, enhance the penetration of lidocaine relatively to the vehicle (without enhancer). The conjugates of oleic acid (C18:1(n-9)) and linoleic acid (C18:2(n-6)) with PG have demonstrated a similar enhancing effect as the corresponding free fatty acids. Interestingly, although the mono- or the di- conjugates of alpha-linolenic acid (C18:3(n-3)) with PG enhanced the lidocaine flux as the other two fatty acid conjugates, they resulted in a reduced permeability as compared to the action of their free acid. In addition, the mono-conjugates of alpha-linolenic acid (C18:3(n-3)) with PG exhibited elevated skin irritation in rabbits (relative to the fatty acid alone) compared to the significantly reduced irritation of oleate-PG and linoeate-PG mono-conjugates. In conclusion, except saturated FA-PG and alpha-linolenic acid (C18:3(n-3)) - PG mono-conjugates, unsaturated fatty acids (e.g., oleic and linoleic acids) after conjugation to PG may be safe and effective enhancers for delivering topical drugs.     

Spectroscopic characterization of red perylimide/surfactant nanocomposites

Novel photoluminescent materials formed by some selected surfactants, metal derivatives of bis(2-ethylhexyl) sulfosuccinate (M(AOT) _n ; M = Na⁺, Co²⁺, Er³⁺ and Yb³⁺), bis(2-ethylhexyl) amine (BEEA), bis(2-ethylhexy1) phosphoric acid (HDEHP) and a 1:1 BEEA/HDEHP mixture, doped with the red perylimide (ROT-300) have been prepared, and their optical properties have been tested by absorption spectroscopy and steady state and time-resolved fluorescence. Experimental results show spectral shifts of the typical ROT-300 absorption and fluorescence bands with respect to that in apolar solvent medium. Data analysis leads consistently to attribute this feature mainly to the freezing of the diffusive movement of the dye molecules confined in the nanodomains of the surfactant liquid crystals, whilst minor effects can be due to interaction with the surfactant polar groups. Potentialities of these novel luminescent nanostructured composites as dye lasers, optical amplifiers and solar concentrators have been highlighted. In particular, under optical pumping using a pulse laser, amplified spontaneous fluorescence emission of the ROT-300/HDEHP system above an excitation energy threshold value of about 725 mJ cm⁻² was observed.     

Synthesis,characterization and antibacterial activity of superparamagnetic nanoparticles modified with glycol chitosan

Iron oxide nanoparticles (IONPs) were synthesized by coprecipitation of iron salts in alkali media followed by coating with glycol chitosan (GC-coated IONPs). Both bare and GC-coated IONPs were subsequently characterized and evaluated for their antibacterial activity. Comparison of Fourier transform infrared spectra and thermogravimetric data of bare and GC-coated IONPs confirmed the presence of GC coating on IONPs. Magnetization curves showed that both bare and GC-coated IONPs are superparamagnetic and have saturation magnetizations of 70.3 and 59.8 emu g⁻¹, respectively. The IONP size was measured as ∼8–9 nm by transmission electron microscopy, and their crystal structure was assigned to magnetite from x-ray diffraction patterns. Both bare and GC-coated IONPs inhibited the growths of Escherichia coli ATCC 8739 and Salmonella enteritidis SE 01 bacteria better than the antibiotics linezolid and cefaclor, as evaluated by the agar dilution assay. GC-coated IONPs showed higher potency against E. coli O157:H7 and Staphylococcus aureus ATCC 10832 than bare IONPs. Given their biocompatibility and antibacterial properties, GC-coated IONPs are a potential nanomaterial for in vivo applications.     

Synthesis,characterization and antibacterial activity of superparamagnetic nanoparticles modified with glycol chitosan

Abstract

Iron oxide nanoparticles (IONPs) were synthesized by coprecipitation of iron salts in alkali media followed by coating with glycol chitosan (GC-coated IONPs). Both bare and GC-coated IONPs were subsequently characterized and evaluated for their antibacterial activity. Comparison of Fourier transform infrared spectra and thermogravimetric data of bare and GC-coated IONPs confirmed the presence of GC coating on IONPs. Magnetization curves showed that both bare and GC-coated IONPs are superparamagnetic and have saturation magnetizations of 70.3 and 59.8 emu g^?1, respectively. The IONP size was measured as ～8–9 nm by transmission electron microscopy, and their crystal structure was assigned to magnetite from x-ray diffraction patterns. Both bare and GC-coated IONPs inhibited the growths of Escherichia coli ATCC 8739 and Salmonella enteritidis SE 01 bacteria better than the antibiotics linezolid and cefaclor, as evaluated by the agar dilution assay. GC-coated IONPs showed higher potency against E. coli O157:H7 and Staphylococcus aureus ATCC 10832 than bare IONPs. Given their biocompatibility and antibacterial properties, GC-coated IONPs are a potential nanomaterial for in vivo applications.     

Influence of urea, isopropanol, and propylene glycol on rutin in vitro release from cosmetic semisolid systems estimated by factorial design

Rutin, one of the major flavonoids found in an assortment of plants, was reported to act as a sun protection factor booster with high anti-UVA defense, antioxidant, antiaging, and anticellulite, by improvement of the cutaneous microcirculation. This research work aimed at evaluating the rutin in vitro release from semisolid systems, in vertical diffusion cells, containing urea, isopropanol and propylene glycol, associated or not, according to the factorial design with two levels with center point. Urea (alone and in association with isopropanol and propylene glycol) and isopropanol (alone and in association with propylene glycol) influenced significant and negatively rutin liberation in diverse parameters: flux (microg/cm(2).h); apparent permeability coefficient (cm/h); rutin amount released (microg/cm(2)); and liberation enhancement factor. In accordance with the results, the presence of propylene glycol 5.0% (wt/wt) presented statistically favorable to promote rutin release from this semisolid system with flux = 105.12 +/- 8.59 microg/cm(2).h; apparent permeability coefficient = 7.01 +/- 0.572 cm/h; rutin amount released = 648.80 +/- 53.01 microg/cm(2); and liberation enhancement factor = 1.21 +/- 0.07.     

In-situ forming biodegradable glycol chitosan-based hydrogels: Synthesis,characterization, and chondrocyte culture

In-situ forming hydrogels from thiolated glycol chitosan (GCH-SH) and vinyl sulfone-modified PEG (PL-VS) were designed, prepared and successfully applied as biodegradable, non-toxic bio-scaffolds for chondrocyte culture. The hydrogels could be formed in situ under physiological conditions via Michael-type addition between the GCH-SH and PL-VS at a low polymer concentration of 1–3% (w/v). Gelation times varied from 0.75 to 50 min, depending on the polymer concentration and the arm number of PEG-VS. Moreover, a high arm number and a high polymer concentration may lead to efficient network formation of GCH-SH/PEG-VS hydrogels. These hydrogels were found biodegradable in the presence of lysozyme, a cationic protein in the body, for a long period of time. Rheological studies indicated that these hydrogels generally displayed highly elastic property and had higher mechanical strength than those from thiolated hyaluronic acid/PEG-VS reported previously. SEM observation revealed that these hydrogels possessed well-interconnected microporous morphology. Besides these, the chondrocytes could be incorporated and homogeneously distributed in the hydrogel based on GCH-SH and 4-arm PL-VS. Importantly, after cell culture of 14 days, the chondrocytes in the hydrogel remained viable, as determined by a live–dead assay, and the cells kept their round chondrocytic phenotype. These results suggest that Michael-type addition is an effective method in the preparation of in-situ forming, biodegradable GCH-based hydrogels serving as bio-scaffolds for chondrocyte culture.     

Synthesis of cerium oxide nanoparticles by microwave technique using propylene glycol as a stabilizing agent

Cerium oxide nanoparticles have been synthesized by microwave method using cerium nitrate, propylene glycol and ammonia as a precursors. The material was characterized by XRD, SEM, TEM and UV–visible techniques. XRD analysis revealed all the relevant Bragg’s reflections for face centered cubic crystal structure of cerium oxide. The average particle size was obtained 9 nm from the extrapolation of the Williamson–Hall plot. The value of particle size determined from XRD was in good agreement with the SEM and TEM results. The direct optical band gap was found to be 3.12 eV.     

Phase equilibria,solidification and solid-state transformations of white cast irons containing niobium

Liquid-solid equilibria were studied in the iron-rich corner of the Fe-Cr-C-Nb system, using a combination of several experimental techniques, essentially differential thermal analysis (DTA) and all the usual means of characterization. A modified version of the DTA technique, quench-interrupted DTA, was employed in order to establish the solidification paths. The investigation was focused on the austenitic field for three levels of chromium (15, 9 and 3.5wt%). The corresponding projections of liquidus in the pseudoternary system are proposed. A slight influence of the other solute contents is found in the case of chromium. The occurrence of blocky NbC carbides depends on the solidification time since it is controlled by a coarsening mechanism.[/p]     

Phase formation, sintering behavior, and electrical characteristics of NASICON compounds

The dependence of phase formation, sintering behavior, and electrical characteristics of Sodium Superionic Conductor (NASICON) compounds on sintering temperature, time, and cooling process was investigated. In the von Alpen-type composition Na_3.2Zr_1.3Si_2.2P_0.8O_10.5, ZrO₂ second phase is in thermal equilibrium with crystalline NASICON and liquid phase above 1320°C, and when cooled through 1260–1320°C, the crystalline NASICON was formed by reaction between the ZrO₂ second phase and the liquid phase. Maximum relative densities of 96 and 91% were obtained for compositions Na₃Zr₂Si₂PO₁₂ and Na_3.2Zr_1.3Si_2.2P_0.8O_10.5, respectively. For these compositions, the maximum ionic conductivity and the minimum migration barrier height were 0.45 ohm^–1cm^–1 and 0.07 eV, respectively. The migration barrier height of the high temperature form (space group: R3c) is about 30–40% of that of the low temperature form (space group: C2/c). Ionic conductivity increases with increasing sinterability, and a considerably large amount of glass phase in Na_3.2Zr_1.3Si_2.2P_0.8O_10.5 ceramics significantly lowers ionic conductivity above the transition temperature.     

Preparation of polymeric micelles consisting of poly(propylene glycol) and poly(caprolactone)

The ring-opening polymerization of epsilon-caprolactone (CL) was carried out with polypropylene glycol (PPG) as an initiator in the presence of the monomer activator HCl. Et2O to synthesize poly(epsilon-caprolactone)-poly(propyleneglycol)-poly(epsilon-caprolactone) (PCL-PPG-PCL) triblock copolymers with change of length PPG and PCL. The micelle formation of PCL-PPG-PCL triblock copolymers in an aqueous phase was confirmed by NMR, dynamic light scattering and fluorescence techniques. The critical micelle concentration (CMC) of the PCL-PPG-PCL triblock copolymers, determined from fluorescence measurements, was in range of 1.4 x 10(-3)-4.6 x 10(-3) mg/ml with dependence on block lengths of PPG and PCL. The partition equilibrium constant, K(v), which is an indicator of the hydrophobicity of the micelles of the PCL-PPG-PCL triblock copolymers in aqueous media, was also changed with dependence on length PPG and PCL. We confirmed that the PCL-PPG-PCL triblock copolymers formed micelles and hence may be potential hydrophobic drug carriers.     

Preparation,characterization and dissolution behavior of artemisinin microparticles

In the present study, a modified 4-fluid nozzle spray drier was used to prepare microparticles of a poorly water soluble drug, artemisinin with the aim of improving its solubility. We also investigated the effect of process variables on the physical properties and dissolution rate of spray dried artemisinin. A full factorial experimentally designed study was performed to investigate the following spray drying variables: inlet temperature and feed concentration. The artemisinin powder and spray dried artemisinin microparticles were characterized by scanning electron microscopy (SEM), differential scanning calorimetric (DSC), X-ray diffraction (XRD) and dissolution. SEM study suggested that the inlet temperature and feed concentration impacted on the particle size of the spray dried particles. The crystallinity of spray dried particles was slightly decreased with increasing inlet temperature and concentration. The dissolution of spray dried particles was markedly improved as compared to commercial artemisinin. A dissolution surface-response model was used to elucidate the significant and direct relationships between drug feed concentration and inlet temperature on one hand and dissolution on the other hand. The best dissolution was found to be 117.00 ± 5.15 μg/mL at the drug feed concentration of 10 g/L and inlet temperature of 140 °C.     

Corrosion-electrochemical behavior of aluminum alloys in aqueous ethylene glycol media

Using the method of mathematical design of experiments, we have studied the influence of ethylene glycol concentration and temperature over a wide range of their variation on the corrosion of AMg₃ aluminum alloy. We have established that, irrespective of the ethylene glycol concentration, the maximum corrosion losses are observed at temperatures of 60–70°C. The inhibiting action of ethylene glycol at concentrations exceeding 40% is caused by an increase in the viscosity of the solutions and by the formation of slightly soluble surface complexes of aluminum with ethylene glycol and the products of its oxidation. __________ Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 43, No. 6, pp. 86–93, November–December, 2007.