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1.
Daisuke Sugimori 《Applied microbiology and biotechnology》2009,82(2):351-357
To develop a microbial treatment of edible oil-contaminated wastewater, microorganisms capable of rapidly degrading edible
oil were screened. The screening study yielded a yeast coculture comprising Rhodotorula pacifica strain ST3411 and Cryptococcus laurentii strain ST3412. The coculture was able to degrade efficiently even at low contents of nitrogen ([NH4–N] = 240 mg/L) and phosphorus sources ([PO4–P] = 90 mg/L). The 24-h degradation rate of 3,000 ppm mixed oils (salad oil/lard/beef tallow, 1:1 w/w) at 20°C was 39.8% ± 9.9% (means ± standard deviations of eight replicates). The highest degradation rate was observed at
20°C and pH 8. In a scaled-up experiment, the salad oil was rapidly degraded by the coculture from 671 ± 52.0 to 143 ± 96.7 ppm
in 24 h, and the degradation rate was 79.4% ± 13.8% (means ± standard deviations of three replicates). In addition, a repetitive
degradation was observed with the cell growth by only pH adjustment without addition of the cells. 相似文献
2.
Vicentini FT Casagrande R Verri WA Georgetti SR Bentley MV Fonseca MJ 《AAPS PharmSciTech》2008,9(2):591-596
The purpose of this study was to develop a lyotropic liquid crystalline formulation using the emulsifier vitamin E TPGS and
evaluate its behavior after incorporation of a flavonoid, quercetin. The physical (macro and microscopic), chemical (determination
of quercetin content by the HPLC method) and functional (determination of quercetin antioxidant activity by DPPH• assay) stability of the lamellar liquid crystalline formulation containing flavonoid was evaluated when stored at 4 ± 2 °C;
30 ± 2 °C/70 ± 5% RH (relative humidity) and 40 ± 2 °C/70 ± 5% RH during 12 months. The lamellar liquid crystalline structure
of the formulation was maintained during the experiment, however chemical and functional stability results showed a great
influence of the storage period in all conditions tested. A significant decrease in quercetin content (approximately 40%)
was detected during the first month of storage and a similar significant loss in antioxidant activity was detected after 6 months.
The remaining flavonoid content was unchanged during the final 6 months of the experimental period. The results suggest possible
interactions between quercetin and the liquid crystalline formulation, which could inhibit or reduce the quercetin activity
incorporated in the system. In conclusion, the present study demonstrated that incorporation of quercetin (1%) did not affect
the liquid crystalline structure composed of vitamin E TPGS/IPM/PG–H2O (1:1) at 63.75/21.25/15 (w/w/w). Nevertheless, of the total quercetin incorporated in the system only 60% was free to act as an antioxidant. 相似文献
3.
Development of Lipid-Based Nanoparticles for Enhancing the Oral Bioavailability of Paclitaxel 总被引:1,自引:0,他引:1
Pandita D Ahuja A Lather V Benjamin B Dutta T Velpandian T Khar RK 《AAPS PharmSciTech》2011,12(2):712-722
The current research work investigates the potential of solid lipid nanoparticles (SLNs) in improving the oral bioavailability
of paclitaxel. Paclitaxel-loaded SLNs (PTX-SLNs) were prepared by modified solvent injection method using stearylamine as
lipid, soya lecithin and poloxamer 188 as emulsifiers. SLNs were characterized in terms of surface morphology, size and size distribution,
surface chemistry and encapsulation efficiency. Pharmacokinetics and bioavailability studies were conducted in male Swiss
albino mice after oral administration of PTX-SLNs. SLNs exhibited spherical shape with smooth surface as analyzed by transmission
electron microscopy (TEM). The mean particle size of SLNs was 96 ± 4.4 nm with a low polydispersity index of 0.162 ± 0.04
and zeta potential of 39.1 ± 0.8 mV. The drug entrapment efficiency was found to be 75.42 ± 1.5% with a loading capacity of
31.5 ± 2.1% (w/w). Paclitaxel showed a slow and sustained in vitro release profile and followed Higuchi kinetic equations. After oral administration of the PTX-SLNs, drug exposure in plasma
and tissues was ten- and twofold higher, respectively, when compared with free paclitaxel solution. PTX-SLNs produced a high
mean C
max (10,274 ng/ml) compared with that of free paclitaxel solution (3,087 ng/ml). The absorbed drug was found to be distributed
in liver, lungs, kidneys, spleen, and brain. The results suggested that PTX-SLNs dispersed in an aqueous environment are promising
novel formulations that enhanced the oral bioavailability of hydrophobic drugs, like paclitaxel and were quite safe for oral
delivery of paclitaxel as observed by in vivo toxicity studies. 相似文献
4.
The present research work was aimed to formulate clotrimazole encapsulated Cavamax W7 composite ethosomes by injection method
for improved delivery across epidermis. 32 factorial design was used to design nine formulations (F1-F9) and compared with ethosomal formulations (F10-F12). F9 with
vesicle size of 202.8 ± 4.8 nm, highest zeta potential (−83.6 ± 0.96 mV) and %EE of 98.42 ± 0.15 was selected as optimized
composite ethosome and F12 as reference ethosomal formulation. As revealed by transmission electron microscopy F9 vesicles
were more condensed, uniformly spherical in shape than F12 vesicles. Vesicular stability studies indicated F9 to be more stable
as compared to F12. Both F9 and F12 were incorporated in carbopol 934 gel base to get G1–G8 gel formulations and evaluated
for in vitro skin permeability. Cavamax W7 composite ethosomal optimized gel (G5) showed higher in vitro percent cumulative drug permeation (88.53 ± 2.10%) in 8 h and steady state flux (J
ss) of 3.39 ± 1.45 μg/cm2/min against the J
ss of 1.57 ± 0.23 μg/cm2/min for ethosomal gel (G1) and 1.13 ± 0.06 μg/cm2/min for marketed formulation. The J
ss flux of G5 was independent of amount of drug applied/unit area of skin. In vivo confocal laser scanning microscopic study of G5 depicted uniform and deeper penetration of rhodamine B (marker) in epidermis
from Cavamax W7 composite ethosomal gel in comparison to G1. Finally, G5 demonstrated better (p < 0.05) antifungal activity against Candida albicans and Aspergillus niger than G1 thus, signifying that Cavamax W7 composite ethosomes present a superior stable and efficacious vesicular system than
ethosomal formulation for topical delivery of clotrimazole. 相似文献
5.
Valence M. K. Ndesendo Viness Pillay Yahya E. Choonara Lisa C. du Toit Eckhart Buchmann Leith C. R. Meyer Riaz A. Khan Uwe Rosin 《AAPS PharmSciTech》2010,11(2):793-808
The purpose of this study was to develop and evaluate the bioadhesivity, in vitro drug release, and permeation of an intravaginal bioadhesive polymeric device (IBPD) loaded with 3′-azido-3′-deoxythymidine
(AZT) and polystyrene sulfonate (PSS). Modified polyamide 6,10, poly(lactic-coglycolic acid), polyacrylic acid, polyvinyl
alcohol, and ethylcellulose were blended with model drugs AZT and PSS as well as radio-opaque barium sulfate (BaSO4) and then
compressed into caplet devices on a tableting press. One set of devices was coated with 2% w/v pentaerythritol polyacrylic acid (APE-PAA) while another remained uncoated. Thermal analysis was performed on the constituent
polymers as well the IBPD. The changes in micro-environmental pH within the simulated human vaginal fluid due to the presence
of the IBPD were assessed over a period of 30 days. Textural profile analysis indicated that the bioadhesivity of the APE-PAA-coated
devices (3.699 ± 0.464 N; 0.0098 ± 0.0004 J) was higher than that of the uncoated devices (1.198 ± 0.150 N; 0.0019 ± 0.0001 J).
In addition, BaSO4-facilitated X-ray imaging revealed that the IBPD adhered to pig vaginal tissue over the experimental period
of 30 days. Controlled drug release kinetics was obtained over 72 days. During a 24-h permeation study, an increase in drug
flux for both AZT (0.84 mg cm−2 h−1) and PSS (0.72 mg cm−2 h−1) was realized up to 12 h and thereafter a steady-state was achieved. The diffusion and dissolution dynamics were mechanistically
deduced based on a chemometric and molecular structure modeling approach. Overall, results suggested that the IBPD may be
sufficiently bioadhesive with desirable physicochemical and physicomechanical stability for use as a prolonged intravaginal
drug delivery device. 相似文献
6.
Dlugokenski RE Sella SR Guizelini BP Vandenberghe LP Woiciechowski AL Soccol CR Minozzo JC 《Applied microbiology and biotechnology》2011,90(2):713-719
A novel low-cost medium was developed from by-products and wastes from the ethanol agro-industry to replace commercial media
in the production of a steam sterilization biological indicator (BI). Various recovery media were developed using soybean
or sugarcane molasses and vinasse to prepare a self-contained BI. Media performance was evaluated by viability and heat resistance
(D
121 °C value) according to regulatory standards. A medium produced with a soybean vinasse ratio of 1:70 (1.4%) (w/v) produced the results, with D
121 °C = 2.9 ± 0.5 min and Usk = 12.7 ± 2.1 min. The addition of 0.8% (w/v) yeast extract improved the germination of heat-damaged spores. The pH variation from 6.0 to 7.3 resulted in a gradual increase
in the D
121 °C value. The absence of calcium chloride resulted in a decrease in germination, while no significant differences were observed
with starch addition. Soybean vinasses may thus be used as the main component of a culture medium to substitute for commercial
media in the production of self-contained biological indicators. The use of ethanol production waste in this biotechnological
process realized a reliable performance, minimized the environmental impact, and decreased BI production costs while producing
a high quality product. 相似文献
7.
The growth conditions and ochratoxin A (OTA) production of Aspergillus strains were studied in aniseed (Pimpinella anisum L.)-based media. The results showed that methanol/NaHCO3 (50:50, v/v) mixture for extraction and competitive direct ELISA analytical method are capable of detecting low OTA concentrations
in this raw material, which were confirmed by HPLC with fluorescence detection (R
2 = 0.994). In aniseed meal extract agar artificially contaminated with selected fungi, the higher OTA values obtained were
283.8 ± 28.1 μg L-1 for A. carbonarius and between 1.7 ± 0.1 μg L-1 and 16.5 ± 12.8 μg L-1 for A. steynii strains. While the optimal conditions of growth for A. carbonarius and A. steynii are 28°C and 0.98 a
w, the optimal production of OTA was observed at 0.99 a
w for both A. carbonarius and A. steynii but at 22°C and 28°C, respectively. Except in one sample, all the aniseed samples analysed were negative for OTA natural
contamination. This study demonstrates that aniseed can be a matrix capable to contamination with OTA, at least produced by
A. carbonarius and A. steynii strains, regardless of the antimicrobial properties of aniseed essential oil. 相似文献
8.
Surmounting the constraints of limited solubilization efficiency and prime requisite of antioxidant for conventional lipid
formulations, the research work explores an edge over formulation utilizing potential applicability of rice germ oil (RGO)
as a multifunctional excipient. Self-microemulsifying drug delivery system (SMEDDS) of tacrolimus (TAC) was formulated with
RGO, an indigenous source of gamma-oryzanol. Being the same biological source, RGO and rice bran oil (RBO) were compared and
it was found that RGO have more solubilization potential for TAC (2.2-fold) as well as higher antioxidant activity (8.06-fold)
than the RBO. TAC-SMEDDS was prepared using RGO/Capmul PG8 (2:3) as an oil phase, Cremophore EL as a surfactant, and Transcutol
P as a cosurfactant. The approximate particle size of TAC-SMEDDS was found to be 38 nm by dynamic light scattering and 12 nm
by small angle neutron scattering. The in vitro dissolution studies showed complete and rapid drug release in 30 min compared to a plain drug (<5%) and marketed capsule
(<50%). AUC and C
max were found to be 45.05 ± 15.64 ng h/ml and 3.91 ± 1.2 ng/ml for TAC-SMEDDS, 12.59 ± 5.54 ng h/ml and 0.48 ± 0.12 ng/ml for
plain TAC, and 30.23 ± 10.34 ng h/ml and 2.31 ± 0.68 ng/ml for marketed formulation, respectively. The improved pharmacokinetic
profile of TAC-SMEDDS is correlating to the dissolution results. Thus, gamma-oryzanol-enriched RGO acts as a potential multifunctional
excipient for lipid formulations. 相似文献
9.
Synthesis of cyanophycin (multi-l-arginyl-poly-l-aspartic acid, CGP) in recombinant organisms is an important option to obtain sufficiently large amounts of this polymer
with a designed composition for use as putative precursors for biodegradable technically interesting chemicals. Therefore,
derivates of CGP, harbouring a wider range of constituents, are of particular interest. As shown previously, cyanophycin synthetases
with wide substrate ranges incorporate other amino acids than arginine. Therefore, using an organism, which produces the required
supplement by itself, was the next logical step. Former studies showed that Pseudomonas putida strain ATCC 4359 is able to produce large amounts of l-citrulline from l-arginine. By expressing the cyanophycin synthetase of Synechocystis sp. PCC 6308, synthesis of CGP was observed in P. putida ATCC 4359. Using an optimised medium for cultivation, the strain was able to synthesise insoluble CGP amounting up to 14.7 ± 0.7%
(w/w) and soluble CGP amounting up to 28.7 ± 0.8% (w/w) of the cell dry matter, resulting in a total CGP content of the cells of 43.4% (w/w). HPLC analysis of the soluble CGP showed that it was composed of 50.4 ± 1.3 mol % aspartic acid, 32.7 ± 2.8 mol % arginine,
8.7 ± 1.6 mol % citrulline and 8.3 ± 0.4 mol % lysine, whereas the insoluble CGP contained less than 1 mol % of citrulline.
Using a mineral salt medium with 1.25 or 2% (w/v) sodium succinate, respectively, plus 23.7 mM l-arginine, the cells synthesised insoluble CGP amounting up to 25% to 29% of the CDM with only a very low citrulline content. 相似文献
10.
Julie Marmet Benoît Pisanu Jean-Louis Chapuis 《European Journal of Wildlife Research》2009,55(5):497-504
Home range size, range overlap, and multiyear site fidelity were investigated for introduced Siberian chipmunks (Tamias sibiricus) in a French suburban forest from bimonthly trapping sessions for 4 years (2004–2007). Annual home range sizes (100% minimum
convex polygon, ±SE) were estimated from 39 trapping histories of 28 different adult residents. Males (N = 13, 1.86 ± 0.32 ha) had a home range 2.5 times larger than females (N = 26, 0.71 ± 0.08 ha); a male home range included significantly more trapping centers (arithmetic mean of capture locations)
of females (5.5 ± 0.7) than of males (2.3 ± 0.5). Chipmunks exhibited strong multiyear site fidelity: mean distance between
annual trapping centers of individuals trapped over two successive years was small (N = 82, 26 ± 2 m) compared to the largest home range length (ranging from 36 to 281 m); overlap between annual home range sizes
of residents was 84 ± 5% (N = 11). These results improve our understanding of the space occupation of this unknown species in a novel environment. 相似文献
11.
Acinetobacter sp. XMZ-26 (ACCC 05422) was isolated from soil samples obtained from glaciers in Xinjiang Province, China. The partial nucleotide
sequence of a lipase gene was obtained by touchdown PCR using degenerate primers designed based on the conserved domains of
cold-adapted lipases. Subsequently, a complete gene sequence encoding a 317 amino acid polypeptide was identified. Our novel
lipase gene, lipA, was overexpressed in Escherichia coli. The recombinant protein (LipA) was purified by Ni-affinity chromatography, and then deeply characterised. The LipA resulted
to hydrolyse pNP esters of fatty acids with acyl chain length from C2 to C16, and the preferred substrate was pNP octanoate showing a k
cat = 560.52 ± 28.32 s−1, K
m = 0.075 ± 0.008 mM, and a k
cat/K
m = 7,377.29 ± 118.88 s−1 mM−1. Maximal LipA activity was observed at a temperature of 15°C and pH 10.0 using pNP decanoate as substrate. That LipA peaked at such a low temperature and remained most activity between 5°C and 35°C indicated
that it was a cold-adapted enzyme. Remarkably, this lipase retained much of its activity in the presence of commercial detergents
and organic solvents, including Ninol, Triton X-100, methanol, PEG-600, and DMSO. This cold-adapted lipase may find applications
in the detergent industry and organic synthesis. 相似文献
12.
Four species of brown seaweeds, namely Sargassum baccularia, Sargassum binderi, Sargassum siliquosum and Turbinaria conoides, harvested from Port Dickson, Negeri Sembilan, Malaysia were analysed for ash content, alginate yield and alginate properties.
Seaweeds calcined at 450°C were found to have low amount of non-combustible residue as these were not contaminated by calcareous
animals. Alginate was extracted from these seaweeds by two methods: hot and cold. In the hot method, the storing time was
3 h and the processing temperature was 50°C, whilst in the cold method, the sample was stored overnight at room temperature.
Higher yield of alginate was obtained by the hot method compared to the cold method, but alginate extracted by the cold method
gave higher molecular weight. In the hot method, 49.9% of alginate was extracted from S. siliquosum, followed by T. conoides (41.4%), S. binderi (38.9%) and S. baccularia (26.7%). Alginate extracted from T. conoides has an average molecular weight, M
w, of 8.06 × 105 g mol−1, whereas alginate from S. siliquosum was the lowest in M
w (4.81 × 105 g mol−1) when the extraction was done at room temperature. Alginate extracted from S. baccularia was found to be very heat-sensitive. Its M
w has dropped more than 83%, from 7.52 × 105 to 1.23 × 105 g mol−1, when the extraction temperature was raised. The effect of heat on the extent of depolymerisation of the alginate molecule
of the other three brown seaweed species was less significant, with decrease in molecular weight ranging between 13% and 16%. 相似文献
13.
In this study, we have formulated chitosan-coated sodium alginate microparticles containing meloxicam (MLX) and aimed to investigate
the correlation between in vitro release and in vivo absorbed percentages of meloxicam. The microparticle formulations were prepared by orifice ionic gelation method with two
different sodium alginate concentrations, as 1% and 2% (w/v), in order to provide different release rates. Additionally, an oral solution containing 15 mg of meloxicam was administered
as the reference solution for evaluation of in vitro/in vivo correlation (ivivc). Following in vitro characterization, plasma levels of MLX and pharmacokinetic parameters [elimination half-life (t
1/2), maximum plasma concentration (C
max), time for C
max (t
max)] after oral administration to New Zealand rabbits were determined. Area under plasma concentration–time curve (AUC0–∞) was calculated by using trapezoidal method. A linear regression was investigated between released% (in vitro) and absorbed% (in vivo) with a model-independent deconvolution approach. As a result, increase in sodium alginate content lengthened in vitro release time and in vivo t
max value. In addition, for ivivc, linear regression equations with r
2 values of 0.8563 and 0.9402 were obtained for microparticles containing 1% and 2% (w/v) sodium alginate, respectively. Lower prediction error for 2% sodium alginate formulations (7.419 ± 4.068) compared to 1%
sodium alginate formulations (9.458 ± 5.106) indicated a more precise ivivc for 2% sodium alginate formulation. 相似文献
14.
This investigation was undertaken to evaluate practical feasibility of site specific pulmonary delivery of liposomal encapsulated
Dapsone (DS) dry powder inhaler for prolonged drug retention in lungs as an effective alternative in prevention of Pneumocystis carinii pneumonia (PCP) associated with immunocompromised patients. DS encapsulated liposomes were prepared by thin film evaporation
technique and resultant liposomal dispersion was passed through high pressure homogenizer. DS nano-liposomes (NLs) were separated
by ultra centrifugation and characterized. NLs were dispersed in phosphate buffer saline (PBS) pH 7.4 containing different
carriers like lactose, sucrose, and hydrolyzed gelatin, and 15% l-leucine as antiadherent. The resultant dispersion was spray dried and spray dried formulation were characterized to ascertain
its performance. In vitro pulmonary deposition was assessed using Andersen Cascade Impactor as per USP. NLs were found to have average size of 137 ± 15 nm,
95.17 ± 3.43% drug entrapment, and zeta potential of 0.8314 ± 0.0827 mV. Hydrolyzed gelatin based formulation was found to
have low density, good flowability, particle size of 7.9 ± 1.1 μm, maximum fine particle fraction (FPF) of 75.6 ± 1.6%, mean
mass aerodynamic diameter (MMAD) 2.2 ± 0.1 μm, and geometric standard deviation (GSD) 2.3 ± 0.1. Developed formulations were
found to have in vitro prolonged drug release up to 16 h, and obeys Higuchi's Controlled Release model. The investigation provides a practical approach
for direct delivery of DS encapsulated in NLs for site specific controlled and prolonged release behavior at the site of action
and hence, may play a promising role in prevention of PCP. 相似文献
15.
Ribitsch D Karl W Wehrschütz-Sigl E Tutz S Remler P Weber HJ Gruber K Stehr R Bessler C Hoven N Sauter K Maurer KH Schwab H 《Applied microbiology and biotechnology》2009,81(5):875-886
In the course of a microbial screening of soil samples for new oxidases, different enrichment strategies were carried out.
With choline as the only carbon source, a microorganism was isolated and identified as Arthrobacter nicotianae. From this strain, a gene coding for a choline oxidase was isolated from chromosomal DNA. This gene named codA was cloned in Escherichia coli BL21-Gold and the protein (An_CodA) heterologously overexpressed as a soluble intracellular protein of 59.1 kDa. Basic biochemical characterization of
purified protein revealed a pH optimum of 7.4 and activity over a broad temperature range (15–70 °C). Specific activities
were determined toward choline chloride (4.70 ± 0.12 U/mg) and the synthetic analogs bis(2-hydroxyethyl)-dimethylammonium
chloride (0.05 ± 0.45 × 10–2 U/mg) and tris-(2-hydroxyethyl)-methylammonium methylsulfate (0.01 ± 0.12 × 10–2 U/mg). With increasing number of oxidizable groups, a significant decrease in activity was noted. Determination of kinetic
parameters in atmorspheric oxygen resulted in K
M = 1.51 ± 0.09 mM and V
max = 42.73 ± 0.42 mU/min for choline chloride and K
M = 4.77 ± 0.76 mM and V
max = 48.40 ± 2.88 mU/min for the reaction intermediate betaine aldehyde respectively. Nuclear magnetic resonance spectroscopic
analysis of the products formed during the enzyme reaction with choline chloride showed that in vitro the intermediate betaine
aldehyde exists also free in solution. 相似文献
16.
Golam Kibria Monzurul Amin Roni Mohammad Shahriarul Absar Reza-ul Jalil 《AAPS PharmSciTech》2008,9(4):1240-1246
The present study was designed to investigate the effect of two plasticizers, i.e., triethyl citrate (TEC) and polyethylene
glycol 6000 (PEG 6000) on the in vitro release kinetics of diclofenac sodium from sustained-release pellets. Ammonio methacrylate copolymer type B (Eudragit RS
30 D) is used as the release-retarding polymer. Both plasticizers were used at 10% and 15% (w/w) of Eudragit RS 30 D. Pellets were prepared by powder layering technology and coated with Eudragit RS 30 D by air suspension
technique. Thermal properties of drug and drug-loaded beads were studied using differential scanning calorimeter (DSC). DSC
thermogram represented the identity of raw materials and exhibited no interaction or complexation between the active and excipients
used in the pelletization process. Dissolution study was performed by using USP apparatus 1. No significant difference was
observed among the physical properties of the coated pellets of different batches. When dissolution was performed as pure
drug, about 8.22% and 90% drug was dissolved at 2 h in 0.1 N HCl and at 30 min in buffer (pH 6.8), respectively. From all
formulations, the release of drug in acid media was very negligible (maximum 1.8 ± 0.08% at 2 h) but in buffer only 12% and
30% drug was released at 10 h from coated pellets containing TEC and PEG 6000, respectively, indicating that Eudragit RS 30
D significantly retards the drug release rate and that drug release was varied according to the type and amount of plasticizers
used. The amount of TEC in coating formulation significantly effected drug release (p < 0.001), but the effect of PEG 6000 was not significant. Formulations containing PEG 6000 released more drug (98.35 ± 2.35%)
than TEC (68.01 ± 1.04%) after 24 h. Different kinetic models like zero order, first order, and Higuchi were used for fitting
drug release pattern. Zero order model fitted best for diclofenac release in all formulations. Drug release mechanism was
derived with Korsmeyer equation. 相似文献
17.
The present investigation was aimed at developing cytarabine-loaded poly(lactide-coglycolide) (PLGA)-based biodegradable nanoparticles
by a modified nanoprecipitation which would have sustained release of the drug. Nine batches were prepared as per 32 factorial design to optimize volume of the co-solvent (0.22–0.37 ml) and volume of non-solvent (1.7–3.0 ml). A second 32 factorial design was used for optimization of drug: polymer ratio (1:5) and stirring time (30 min) based on the two responses,
mean particle size (125 ± 2.5 nm), and percentage entrapment efficiency (21.8 ± 2.0%) of the Cyt-PLGA nanoparticles. Optimized
formulation showed a zeta potential of −29.7 mV indicating good stability; 50% w/w of sucrose in Cyt-PLGA NP was added successfully as cryoprotectant during lyophilization for freeze-dried NPs and showed
good dispersibility with minimum increase in their mean particle sizes. The DSC thermograms concluded that in the prepared
PLGA NP, the drug was present in the amorphous phase and may have been homogeneously dispersed in the PLGA matrix. In vitro drug release from the pure drug was complete within 2 h, but was sustained up to 24 h from PLGA nanoparticles with Fickian
diffusion. Stability studies showed that the developed PLGA NPs should be stored in the freeze-dried state at 2–8°C where
they would remain stable in terms of both mean particle size and drug content for 2 months. 相似文献
18.
Xue-Qin Xie Jie Wang Bao-Fu Huang Sheng-Hua Ying Ming-Guang Feng 《Applied microbiology and biotechnology》2010,86(5):1543-1553
A superoxide dismutase (SOD) was characterized from Beauveria bassiana, a fungal entomopathogen widely applied to insect control. This 209-aa enzyme (BbSod2) showed no more than 71% sequence identity
to other fungal Mn-SODs, sharing all conserved residues with the Mn-SOD family and lacking a mitochondrial signal. The SOD
activity of purified BbSod2 was significantly elevated by Mn2+, suppressed by Cu2+ and Zn2+ but inhibited by Fe3+. Overexpressing the enzyme in a BbSod2-absent B. bassiana strain enhanced its SOD activity (107.2 ± 6.1 U mg−1 protein) by 4–10-fold in different transformants analyzed. The best BbSod2-transformed strain with the SOD activity of 1,157.9 ± 74.7 U mg−1 was 93% and 61% more tolerant to superoxide-generating menadione in both colony growth (EC50 = 2.41 ± 0.03 versus 1.25 ± 0.01 mM) and conidial germination (EC50 = 0.89 ± 0.06 versus 0.55 ± 0.07 mM), and 23% more tolerant to UV-B irradiation (LD50 = 0.49 ± 0.02 versus 0.39 ± 0.01 J cm−2). Its virulence to Spodoptera litura larvae was enhanced by 26% [LT50 = 4.5 (4.2–4.8) versus 5.7 (5.2–6.4) days]. Our study highlights for the first time that the Mn2+-cofactored, cytosolic BbSod2 contributes significantly to the virulence and stress tolerance of B. bassiana and reveals possible means to improving field persistence and efficacy of a fungal formulation by manipulating the antioxidant
enzymes of a candidate strain. 相似文献
19.
The aim of the present investigation was to evaluate microemulsion as a vehicle for dermal drug delivery and to develop microemulsion-based
gel of terbinafine for the treatment of onychomycosis. D-optimal mixture experimental design was adopted to optimize the amount
of oil (X
1), Smix (mixture of surfactant and cosurfactant; X
2) and water (X
3) in the microemulsion. The formulations were assessed for globule size (in nanometers; Y
1) and solubility of drug in microemulsion (in milligrams per milliliter; Y
2). The microemulsion containing 5.75% oil, 53.75% surfactant–cosurfactant mixture and 40.5% water was selected as the optimized
batch. The globule size and solubility of the optimized batch were 18.14 nm and 43.71 mg/ml, respectively. Transmission electron
microscopy showed that globules were spherical in shape. Drug containing microemulsion was converted into gel employing 0.75%
w/w carbopol 934P. The optimized gel showed better penetration and retention in the human cadaver skin as compared to the commercial
cream. The cumulative amount of terbinafine permeated after 12 h was 244.65 ± 18.43 μg cm−2 which was three times more than the selected commercial cream. Terbinafine microemulsion in the gel form showed better activity
against Candida albicans and Trichophyton rubrum than the commercial cream. It was concluded that drug-loaded gel could be a promising formulation for effective treatment
of onychomycosis. 相似文献
20.
Tatiana Kugelmeier Rodrigo del Rio do Valle Marcelo Alcindo de Barros Vaz Guimarães José Augusto Pereira Carneiro Muniz Frederico Ozanan Barros Monteiro Cláudio Alvarenga de Oliveira 《International journal of primatology》2011,32(3):605-615
A better understanding of a species’ reproductive physiology can help conservation programs to manage primates in the wild
and develop assisted reproductive technologies in captivity. We investigated whether measurements of fecal progestin and estrogen
metabolites obtained by a radioimmunoassay could be used to monitor the ovarian cycle of Alouatta caraya. We also compared the occurrence of vaginal bleeding with the hormone profiles. We collected fecal samples from 3 adult and
1 subadult captive female over 5 mo and performed vaginal cytology for the adults. The interval between fecal progestin surges
in the adult females was 19.11 ± 2.14 d (n = 18 cycles). Fecal progestin concentrations remained at basal values for 9.83 ± 2.21 d (n = 18) and rose to elevated values for 9.47 ± 0.72 d (n = 19). The subadult female showed basal levels of fecal estrogen and progestin concentrations throughout the study, suggesting
that our hormone measurements are valid to monitor the ovarian cycle. Bleeding periods coincided with basal levels of fecal
estrogens and progestin at intervals of 19.8 ± 0.9 d and lasted for 4.1 ± 1.0 d. Although we obtained these data from only
3 individuals, the results indicate that this species likely has a menstrual-type ovarian cycle. These data provide the first
endocrine profile for the Alouatta caraya ovarian cycle and are similar to results obtained for other howler species. This similarity is important for comparative
studies of howlers, allowing for a better understanding of their reproductive physiology and contributing to a critical information
base for managing Alouatta species. 相似文献