共查询到20条相似文献,搜索用时 31 毫秒
1.
This study describes a simple chromatographic method for the simultaneous analyses of phosphatidylcholine (PC) and its hydrolytic degradation products: lysophosphatidylcholine (LPC) and free fatty acids (FFA). Quantitative determination of PC, LPC, and FFA is essential in order to assure safety and to accurately assess the shelf life of phospholipid-containing products. A single-run normal-phase high-performance liquid chromatography (HPLC) with evaporative light scattering detector has been developed. The method utilizes an Allsphere silica analytical column and a gradient elution with mobile phases consisting of chloroform: chloroform–methanol (70:30%, v/v) and chloroform–methanol–water–ammonia (45:45:9.5:0.5%, v/v/v/v). The method adequately resolves PC, LPC, and FFA within a run time of 25 min. The quantitative analysis of PC and LPC has been achieved with external standard method. The free fatty acids were analyzed as a group using linoleic acid as representative standard. Linear calibration curves were obtained for PC (1.64–16.3 μg, r2 = 0.9991) and LPC (0.6–5.0 μg, r2 = 0.9966), while a logarithmic calibration curve was obtained for linoleic acid (1.1–5.8 μg, r2 = 0.9967). The detection and quantification limits of LPC and FFA were 0.04 and 0.1 μg, respectively. As a means of validating the applicability of the assay to pharmaceutical products, PC liposome was subjected to alkaline hydrolytic degradation. Quantitative HPLC analysis showed that 97% of the total mass balance for PC could be accounted for in liposome formulation. The overall results show that the HPLC method could be a useful tool for chromatographic analysis, stability studies, and formulation characterization of phospholipid-based pharmaceuticals.KEY WORDS: evaporative light scattering detection, free fatty acid, lysophosphatidylcholine, phosphatidylcholine 相似文献
2.
Chintan J. Bhanushali Ahmed S. Zidan Ziyaur Rahman Muhammad J. Habib 《AAPS PharmSciTech》2013,14(4):1313-1320
Ethionamide (ETA) and pyrazinamide (PZA) are considered the drugs of choice for the treatment of multidrug-resistant tuberculosis. Current methods available in the literature for simultaneous determination of ETA and PZA have low sensitivity or involve column modifications with lipophilic cations. The aim of this study was to develop a simple and validated reversed-phase ion-pair HPLC method for simultaneous determination of ETA and PZA for the characterization of polymeric-based porous inhalable microparticles in in vitro and spiked human serum samples. Chromatographic separation was achieved on a Phenomenex C18 column (250 mm × 4.6 mm) using a Shimadzu LC 10 series HPLC. The mobile phase consisted of A: 0.01% trifluoroacetic acid in distilled water and B: ACN/MeOH at 1:1 v/v. Gradient elution was run at a flow rate of 1.5 mL/min and a fixed UV wavelength of 280 nm. The validation characteristics included accuracy, precision, linearity, analytical range, and specificity. Calibration curves at seven levels for ETA and PZA were linear in the analytical range of 0.1–3.0 μg/mL with correlation coefficient of r2 > 0.999. Accuracy for both ETA and PZA ranged from 94 to 106% at all quality control (QC) standards. The method was precise with relative standard deviation less than 2% at all QC levels. Limits of quantitation for ETA and PZA were 50 and 70 ng/mL, respectively. There was no interference from either the polymeric matrix ions or the biological matrix in the analysis of ETA and PZA.Key words: ethionamide, HPLC, microparticles, pyrazinamide, tuberculosis 相似文献
3.
Amit Vashishtha Brijesh Rathi Sandeep Kaushik K. K. Sharma Suman Lakhanpaul 《Physiology and Molecular Biology of Plants》2013,19(4):537-545
Females of lac insects especially of Kerria lacca (Kerr) secret a resin known as lac for their own protection, which has tremendous applications. Lac insect completes its lifecycle on several host taxa where it exclusively feeds on phloem sap but Schleichera oleosa (Lour.) Oken, Butea monosperma (Lam.) and Ziziphus mauritiana (Lam.) are its major hosts. Analysis of phloem sap constituents as well as hemolymph of lac insect is important because it ultimately gets converted into lac by insect intervention. Main phloem sap constituent’s viz. sugars and free amino acids and hemolymph of lac insect were analyzed using HPLC and tandem mass spectrometry, respectively. The results were transformed to relative percentage of the total sugars and free amino acids analyzed in each sample for comparison among lac insect hemolymph and the phloem sap of the three different host taxa. Sucrose (58.9 ± 3.6–85.6 ± 0.9) and trehalose (62.3 ± 0.4) were the predominant sugars in phloem sap of three taxa and hemolymph of lac insect, respectively. Glutamic acid (33.1 ± 1.4–39.8 ± 1.4) was found to be main amino acid among the phloem sap of three taxa while tyrosine (61 ± 2.6) was the major amino acid in hemolymph of lac insect. The relative percentage of non-essential amino acids (60.8 %–69.9 %) was found to be more in all the three host taxa while essential amino acids (30.1 %–35.4 %) were present at a lower relative percentage. In contrast to this, the relative percentage of essential amino acids (81.9 %) was observed to be higher as compared to non-essential amino acids (17.7 %) in lac insect hemolymph. These results led to the detection of lac insect’s endosymbionts. Moreover, this study revealed a clue regarding the importance of development of a synthetic diet for this insect so that a precise pathway of lac biosynthesis could be investigated for thorough understanding. 相似文献
4.
Tetrandrine (TET) is a poorly water-soluble bisbenzylisoquinoline alkaloid. In this study, TET solid lipid nanoparticles (SLNs) were prepared by a melt–emulsification and ultrasonication technique. Precirol® ATO 5, glyceryl monostearate, and stearic acid were used as the lipid matrix for the SLNs, while Lipoid E80, Pluronic F68, and sodium deoxycholate were used as emulsifying and stabilizing agents. The physicochemical characteristics of the TET–SLNs were investigated when it was found that the mean particle size and zeta potential of the TET–SLNs were 134 ± 1.3 nm and −53.8 ± 1.7 mV, respectively, and the entrapment efficiency (EE) was 89.57% ± 0.39%. Differential scanning calorimetry indicated that TET was in an amorphous state in SLNs. TET–SLNs exhibited a higher release rate at a lower pH and a lower release rate at a higher pH. The release pattern of the TET–SLNs followed the Weibull model. The pharmacokinetics of TET–SLNs after intravenous administration to male rats was studied. TET–SLN resulted in a higher plasma concentration and lower clearance. The biodistribution study indicated that TET–SLN showed a high uptake in reticuloendothelial system organs. In conclusion, TET–SLNs with a small particle size, and high EE, can be produced by the method described in this study. The SLN system is a promising approach for the intravenous delivery of tetrandrine.Key words: characterization, pharmacokinetics, preparation, solid lipid nanoparticles, tetrandrine 相似文献
5.
Iqbal Ahmad Kiran Qadeer Saima Zahid Muhammad Ali Sheraz Tehmina Ismail Waqar Hussain Izhar Ahmad Ansari 《AAPS PharmSciTech》2014,15(5):1324-1333
The degradation kinetics of 5 × 10−5 M cyanocobalamin (B12) and hydroxocobalamin (B12b) in the presence of ascorbic acid (AH2) was studied in the pH range of 1.0–8.0. B12 is degraded to B12b which undergoes oxidation to corrin ring cleavage products. B12b alone is directly oxidized to the ring cleavage products. B12 and B12b in degraded solutions were simultaneously assayed by a two-component spectrometric method at 525 and 550 nm without interference from AH2. Both degrade by first-order kinetics and the values of the rate constants at pH 1.0–8.0 range from 0.08 to 1.05 × 10−5 s−1 and 0.22–7.62 × 10−5 s−1, respectively, in the presence of 0.25 × 10−3 M AH2. The t1/2 values of B12 and B12b range from 13.7 to 137.5 h and 2.5–87.5 h, respectively. The second-order rate constants for the interaction of AH2 with B12 and B12b are 0.05–0.28 × 10−2 and 1.10–30.08 × 10−2 M−1 s−1, respectively, indicating a greater effect of AH2 on B12b compared to that of B12. The kobs–pH profiles for both B12 and B12b show the highest rates of degradation around pH 5. The degradation of B12 and B12b by AH2 is affected by the catalytic effect of phosphate ions on the oxidation of AH2 in the pH range 6.0–8.0.KEY WORDS: ascorbic acid, cyanocobalamin, degradation, hydroxocobalamin, kinetics, two-component spectrometry 相似文献
6.
Zhidong Liu Chukwunweike Ikechukwu Okeke Li Zhang Hainan Zhao Jiawei Li Mike Okweesi Aggrey Nan Li Xiujun Guo Xiaochen Pang Lili Fan Lili Guo 《AAPS PharmSciTech》2014,15(2):483-496
Breviscapine is used in the treatment of ischemic cerebrovascular diseases, but it has a low bioavailability in the brain due to its poor physicochemical properties and the activity of P-glycoprotein efflux pumps located at the blood–brain barrier. In the present study, breviscapine-loaded solid lipid nanoparticles (SLN) coated with polyethylene glycol (PEG) derivatives were formulated and evaluated for their ability to enhance brain bioavailability. The SLNs were either coated with polyethylene glycol (40) (PEG-40) stearate alone (Bre-GBSLN-PS) or a mixture of PEG-40 stearate and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-PEG2000 (DSPE-PEG2000) (Bre-GBSLN-PS-DSPE) and were characterized both in vitro and in vivo. The mean particle size, polydispersity index, and entrapment efficiency for Bre-GBSLN-PS and Bre-GBSLN-PS-DSPE were 21.60 ± 0.10 and 22.60 ± 0.70 nm, 0.27 ± 0.01 and 0.26 ± 0.04, and 46.89 ± 0.73% and 47.62 ± 1.86%, respectively. The brain pharmacokinetic parameters revealed that the brain bioavailability of breviscapine from the Bre-GBSLN-PS and Bre-GBSLN-PS-DSPE was significantly enhanced (p < 0.01) with the area under concentration–time curve (AUC) of 1.59 ± 0.39 and 1.42 ± 0.58 μg h/mL of breviscapine, respectively, in comparison to 0.11 ± 0.02 μg h/mL from the commercial breviscapine injection. The ratios of the brain AUC for scutellarin in comparison with the plasma scutellarin AUC for commercial breviscapine injection, Bre-GBSLN-PS, and Bre-GBSLN-PS-DSPE were 0.66%, 2.82%, and 4.51%, respectively. These results showed that though both SLN formulations increased brain uptake of breviscapine, Bre-GBSLN-PS-DSPE which was coated with a binary combination of PEG-40 stearate and DSPE-PEG2000 had a better brain bioavailability than Bre-GBSLN-PS. Thus, the coating of SLNs with the appropriate PEG derivative combination could improve brain bioavailability of breviscapine and can be a promising tool for brain drug delivery.KEY WORDS: breviscapine, microdialysis, mixed PEGylation, P-glycoprotein (P-gp), solid lipid nanoparticles 相似文献
7.
Iqbal Ahmad Zubair Anwar Kefi Iqbal Syed Abid Ali Tania Mirza Adeela Khurshid Aqeela Khurshid Adeel Arsalan 《AAPS PharmSciTech》2014,15(3):550-559
The photolysis of riboflavin (RF) in the presence of acetate buffer (pH 3.8–5.6) and carbonate buffer (pH 9.2–10.8) has been studied using a multicomponent spectrophotometric method for the simultaneous assay of RF and its photoproducts. Acetate and carbonate buffers have been found to catalyze the photolysis reaction of RF. The apparent first-order rate constants for the acetate-catalyzed reaction range from 0.20 to 2.86 × 10−4 s−1 and for the carbonate-catalyzed reaction from 3.33 to 15.89 × 10−4 s−1. The second-order rate constants for the interaction of RF with the acetate and the carbonate ions range from 2.04 to 4.33 × 10−4 M−1 s−1 and from 3.71 to 11.80 × 10−4 M−1 s−1, respectively. The k-pH profile for the acetate-catalyzed reaction is bell shaped and for the carbonate-catalyzed reaction a steep curve. Both HCO3− and CO32 − ions are involved in the catalysis of the photolysis reaction in alkaline solution. The rate constants for the HCO3− and CO32 − ions catalyzed reactions are 0.72 and 1.38 × 10−3 M−1 s−1, respectively, indicating a major role of CO32 − ions in the catalysis reaction. The loss of RF fluorescence in acetate buffer suggests an interaction between RF and acetate ions to promote the photolysis reaction. The optimum stability of RF solutions is observed in the pH range 5–6, which is suitable for pharmaceutical preparations.KEY WORDS: acetate effect, carbonate effect, photolysis, riboflavin, spectrophotometric assay 相似文献
8.
Ragwa M. Farid Mohamed A. Etman Aly H. Nada Abd El Azeem R. Ebian 《AAPS PharmSciTech》2013,14(2):712-718
The aim of this study was to formulate salbutamol sulfate (SS), a model drug, as mucoadhesive in situ gelling inserts having a high potential as nasal drug delivery system bypassing the first-pass metabolism. In situ gelling inserts, each containing 1.4% SS and 2% gel-forming polymer, hydroxypropyl methylcellulose (HPMC), carboxymethylcellulose sodium (CMC Na), sodium alginate (AL), and chitosan (CH) were prepared. The inserts were investigated for their different physicochemical properties. The weight of inserts was 16–27 mg, drug content was 3.9–4.2 mg, thickness ranged between 15 and 28 μm and surface pH was 5–7. Cumulative drug released from the inserts exhibited extended release for more than 10 h following the decreasing order: CH > AL > CMC Na > HPMC. The drug release from CMC Na and AL inserts followed zero-order kinetics while HPMC and CH inserts exhibited non-Fickian diffusion mechanism. The inserts exhibited different water uptake (7–23%) with the smallest values for CH. Differential scanning calorimetry study pointed out possible interaction of SS and oppositely charged anionic polymers (CMC Na and AL). The mucoadhesive in situ gelling inserts exhibited satisfactory mucoadhesive and extended drug release characteristics. The inserts could be used for nasal delivery of SS over about 12 h; bypassing the hepatic first-pass metabolism without potential irritation.KEY WORDS: in situ gelling inserts, mucoadhesion, nasal delivery, salbutamol sulfate 相似文献
9.
Thiagarajan Madheswaran Rengarajan Baskaran Raj Kumar Thapa Jeong Yeon Rhyu Hye Yoon Choi Jong Oh Kim Chul Soon Yong Bong Kyu Yoo 《AAPS PharmSciTech》2013,14(1):45-52
In this study, liquid crystalline nanoparticles (LCN) have been proposed as new carrier for topical delivery of finasteride (FNS) in the treatment of androgenetic alopecia. To evaluate the potential of this nanocarrier, FNS-loaded LCN was prepared by ultrasonication method and characterized for size, shape, in vitro release, and skin permeation–retention properties. The particle size ranged from 153.8 to 170.2 nm with a cubical shape and exhibited controlled release profile with less than 20% of the drug released in the first 24 h. The release profile was significantly altered with addition of different additives. Formulation with lower monoolein exhibited higher skin permeation with a flux rate of 0.061 ± 0.005 μg cm−2 h−1 in 24 h. The permeation however, significantly increased with glycerol, propylene glycol, and polyethylene glycol 400, while it declined for the addition of oleic acid. A similar trend was observed with skin retention study. In conclusion, FNS-loaded LCN could be advocated as a viable alternative for oral administration of the drug.Key words: androgenetic alopecia, finasteride, liquid crystalline nanoparticles, release, skin permeation–retention 相似文献
10.
S. I. Lok D. J. Lok P. van der Weide B. Winkens P. W. Bruggink-André de la Porte P. A. Doevendans R. A. de Weger P. van der Meer N. de Jonge 《Netherlands heart journal》2014,22(9):391-395
Background
There is increasing interest in utilising novel markers of cardiovascular disease risk in patients with chronic heart failure (HF). Recently, it was shown that alpha-1-antichymotrypsin (ACT), an acute-phase protein and major inhibitor of cathpesin G, plays a role in the pathophysiology of HF and may serve as a marker for myocardial distress.Objective
To assess whether ACT is independently associated with long-term mortality in chronic HF patients.Methods
ACT plasma levels were categorised into quartiles. Survival times were analysed using Kaplan-Meier curves and Cox proportional hazards regression, without and with correction for clinically relevant risk factors, including sex, age, duration of HF, kidney function (MDRD), ischaemic HF aetiology and NT-proBNP.Results
Twenty healthy individuals and 224 patients (mean age 71 years, 72 % male, median HF duration 1.6 years) with chronic HF were included. In total, 159 (71 %) patients died. The median survival time was 5.3 (95 % CI 4.5–6.1) years. ACT was significantly elevated in patients (median 433 μg/ml, IQR 279–680) in comparison with controls (median 214 μg/ml, IQR 166–271; p < 0.001). Cox regression analysis demonstrated that ACT was not independently related to long-term mortality in chronic HF patients (crude HR = 1.03, 95 % CI 0.75–1.41, p = 0.871; adjusted HR = 1.12, 95 % CI 0.78–1.60, p = 0.552), which was confirmed by Kaplan-Meier curves.Conclusion
ACT levels are elevated in chronic HF patients, but no independent association with long-term mortality can be established. 相似文献11.
Karunakar Neelam Ravichandran Mahalingam Raj Birudaraj Tom Alfredson Pratap Anne Xiaoling Li Bhaskara R. Jasti 《AAPS PharmSciTech》2009,10(4):1331-1335
The relative bioavailability of chlorothiazide from mucoadhesive polymeric compacts is compared to commercial oral suspension in pigs. A single-dose randomized study was conducted in 12 healthy pigs that are 9–10 weeks old. After overnight fasting, pigs were divided into two groups of six animals. To the first group, a reference product containing 50 mg of chlorothiazide suspension, and in the second group, test product (mucoadhesive compacts) chlorothiazide (50 mg) was administered with 75 mL of water via gastric tubes. Blood samples were collected between 0 to 24 h using catheters inserted into the jugular vein. Plasma was separated by protein precipitation, and chlorothiazide concentrations were determined using a high-performance liquid chromatography method. The mean Tmax and the Cmax of chlorothiazide following the administration of oral suspension and mucoadhesive compacts were 0.58 ± 0.20 h and 682.97 ± 415.69 ng/mL and 2.17 ± 0.98 h and 99.42 ± 124.08 ng/mL, respectively. The Kel and T1/2 of chlorothiazide were found to be 1.06 ± 0.28 h−1 and 0.70 ± 0.21 h from suspension and 0.95 ± 1.11 h−1 and 2.05 ± 1.90 h from the compacts, respectively. The Tmax of mucoadhesive compacts were significantly longer (p < 0.05; 2.17 h) than the reference products (0.58 h), whereas the Cmax of compacts were significantly lower (99 ng/mL) than the reference product (683 ng/mL; p < 0.05). The area under the curve (AUC) of compacts accounts only 50.15% (404.32 ± 449.93 ng h/mL) of the reference product’s AUC (806.27 ± 395.97 ng h/mL). The relative bioavailability of the compacts was lower than that of the suspension, and this may be due to the narrow window of absorption for chlorothiazide.Key words: bioavailability, chlorothiazide, mucoadhesive compacts, pigs 相似文献
12.
Neeraj Kumar Sandeep Soni Thakuri Singh Amit Kumar Farhan Jalees Ahmad Aseem Bhatnagar Gaurav Mittal 《AAPS PharmSciTech》2015,16(6):1270-1280
Medical management of heavy metal toxicity, including radioactive ones, is a cause for concern because of their increased use in energy production, healthcare, and mining. Though chelating agents like EDTA and DTPA in parenteral form are available, no suitable oral formulation is there that can trap ingested heavy metal toxicants in the stomach itself, preventing their systemic absorption. The objective of the present study was to develop and optimize gastro-retentive controlled-release tablets of calcium-disodium edentate (Ca-Na2EDTA). Gastro-retentive tablet of Ca-Na2EDTA was prepared by direct compression method. Thirteen tablet formulations were designed using HPMC-K4M, sodium chloride, and carbopol-934 along with effervescing agents sodium bicarbonate and citric acid. Tablet swelling ability, in vitro buoyancy, and drug dissolution studies were conducted in 0.1 N HCl at 37 ± 0.5°C. Ca-Na2EDTA was radiolabeled with technetium-99m for scintigraphy-based in vivo evaluation. Formula F8 (Ca-Na2EDTA 200 mg, carbopol 100 mg, avicel 55 mg, citric acid 30 mg, NaHCO3 70 mg, NaCl 100 mg, and HPMC 95 mg) was found to be optimum in terms of excellent floating properties and sustained drug release. F8 fitted best for Korsmeyer–Peppas equation with an R2 value of 0.993. Gamma scintigraphy in humans showed mean gastric retention period of 6 h. Stability studies carried out in accordance with ICH guidelines and analyzed at time intervals of 0, 1, 2, 4, and 6 months have indicated insignificant difference in tablet hardness, drug content, total floating duration, or matrix integrity of the optimized formulation. Gastro-retentive, controlled-release tablet of Ca-Na2EDTA was successfully developed using effervescent technique as a potential oral antidote for neutralizing ingested heavy metal toxicity.KEY WORDS: calcium disodium EDTA, controlled-release tablet, gamma scintigraphy, heavy metal decorporation 相似文献
13.
Fungal keratitis is a serious corneal disease that may result in loss of vision. There are limited treatment options available in Iraqi eye hospitals which might be the main reason behind the poor prognosis of many cases. The purpose of this study was to prepare and pharmaceutically evaluate clotrimazole–β-cyclodextrin (CTZ–β-CD) eyedrops then clinically assess its therapeutic efficacy on fungal keratitis compared with extemporaneous amphotericin B eyedrops (0.5% w/v). A CTZ–β-CD ophthalmic solution was prepared and evaluated by various physicochemical, microbiological, and biological tests. The prepared formula was stable in 0.05 M phosphate buffer pH 7.0 at 40 ± 2°C and 75 ± 5% RH for a period of 6 months. Light has no significant effect on the formula’s stability. The CTZ–β-CD eyedrops efficiently complied with the isotonicity, sterility, and antimicrobiological preservative effectiveness tests. Results of the clinical study revealed that 20 (80%) patients showed a favorable response to the CTZ–β-CD eyedrops, while 16 patients (64%) exhibited a favorable response to amphotericin B (P > 0.05). The mean course of treatment was significantly (P < 0.05) less in the CTZ treatment group than in the amphotericin group (21.5 ± 5.2 vs. 28.3 ± 6.4 days, respectively). The CTZ formulation was significantly (P < 0.05) more effective in the management of severe cases and also against Candida sp. than amphotericin B. There was no significant difference (P < 0.05) between both therapies against filamentous fungi. The CTZ–β-CD formulation can be used alternatively to other ophthalmic antimycotic treatment options in developing countries where stability, cost, or efficacy is a limiting factor.Key words: clotrimazole, β-cyclodextrin, eyedrops, fungal keratitis, Iraq 相似文献
14.
Deepika Lodha Nisha Rathore Vinod Kataria N. S. Shekhawat 《Physiology and Molecular Biology of Plants》2014,20(3):375-383
Ephedra foliata Boiss. & Kotschy ex Boiss., (family – Ephedraceae), is an ecologically and economically important threatened Gymnosperm of the Indian Thar Desert. A method for micropropagation of E. foliata using nodal explant of mature female plant has been developed. Maximum bud-break (90 %) of the explant was obtained on MS medium supplemented with 1.5 mg l−1 of benzyl adenine (BA) + additives. Explant produces 5.3 ± 0.40 shoots from single node with 3.25 ± 0.29 cm length. The multiplication of shoots in culture was affected by salt composition of media, types and concentrations of plant growth regulators (PGR’s) and their interactions, time of transfer of the cultures. Maximum number of shoots (26.3 ± 0.82 per culture vessel) were regenerated on MS medium modified by reducing the concentration of nitrates to half supplemented with 200 mg l−1 ammonium sulphate {(NH4) 2SO4} (MMS3) + BA (0.25 mg l−1), Kinetin (Kin; 0.25 mg l−1), Indole-3-acetic acid (IAA; 0.1 mg l−1) and additives. The in vitro produced shoots rooted under ex vitro on soilrite moistened with one-fourth strength of MS macro salts in screw cap bottles by treating the shoot base (s) with 500 mg l−1 of Indole-3-butyric acid (IBA) for 5 min. The micropropagated plants were hardened in the green house. The described protocol can be applicable for (i) large scale plant production (ii) establishment of plants in natural habitat and (iii) germplasm conservation of this endemic Gymnosperm of arid regions. 相似文献
15.
To investigate the possibility of liquid proliposomes being carriers for oral delivery, nimodipine liquid proliposomes-based soft capsules (NPSC) were prepared. Nimodipine proliposomes were characterized by transmission electron microscopy (TEM), conversion rate from proliposomes to liposomes, entrapment efficiency, particle size, and zeta potential. Accelerated stability testing of NPSC was carried out for 3 months at 40 ± 2°C, 75 ± 5% RH. The concentration of nimodipine in plasma of New Zealand rabbits of NPSC, nimodipine soft capsules, and hydrated liposomes was studied. Results showed that nimodipine proliposomes were automatically converted into liposomes when exposed to a water phase in 30 s. The average diameter was 378.6 ± 26.5 nm in distilled water with entrapment efficiency (EE%) of 84.7 ± 5.9%, while the average diameter was 316.9 ± 34.6 nm in 0.1 M hydrochloric acid solution with EE% of 72.8 ± 4.7%. Accelerated stability test showed that there was no change in drug content, particle size, and EE% except for a decrease in dissolution of nimodipine. In vivo experiments, areas under the plasma level-time curve of NPSC and nimodipine-hydrated liposomes increased 2.41 and 2.34 times more than that of nimodipine soft capsules, peak concentration increased 2.87 and 2.92 times, time of peak concentration from 0.75 to 2 and 1 h, respectively. Nimodipine-hydrated liposomes presented similar pharmacokinetic parameters compared with NPSC. Results suggested that NPSC offered a potential way to improve oral delivery of nimodipine.Key words: liquid proliposomes, nimodipine, pharmacokinetics, soft capsules, stability 相似文献
16.
The purpose of this study was to investigate the in vivo distribution and antitumor activity of irinotecan (camptothecin (CPT)-11)-loaded folate-targeted liposome (F-Lip) in tumor-bearing mice following i.v. administration. Folate–poly(ethylene glycol)–distearoylphosphatidylcholine (FA–PEG–DSPE) was synthesized by amide reaction of DSPE–PEG–NH2 and FA. F-Lip modified by FA–PEG–DSPE was prepared by an ammonium sulfate gradient. The mean particle size and entrapment efficiency of F-Lip with negative charge were 197.8 ± 4.58 nm and 91.39 ± 2.34 %, respectively. The distributions of CPT-11 and SN-38 in the tumor after i.v. administration of F-Lip, CPT-11-loaded liposomes (C-Lip), and CPT-11 injection (C-Inj) were far greater with the F-Lip group in comparison to the C-Inj and C-Lip, which might contribute to folate-meditated targeting uptake by the folate receptor on the surface of the tumor cells. The uptake of CPT-11 in the liver and rectum for two liposome groups were all markedly increased as compared to the C-Inj. Moreover, F-Lip exhibited a dose-dependent tumor growth inhibition and superior anticancer activity to C-Lip and C-Inj after i.v. administration. It also showed no significant body weight loss and much lower toxicity on the center immune organs. Therefore, F-Lip may be presented as potential candidates for tumor targeting drug delivery.KEY WORDS: cancer targeting, CPT-11, folate, liposomes, SN-38 相似文献
17.
M. Martínez-Sellés T. Datino L. M. Figueiras-Graillet H. Bueno F. Fernández-Aviles 《Netherlands heart journal》2013,21(11):499-503
Background
The influence of new-onset atrial fibrillation (AF) on the long-term prognosis of nonagenarians who survive acute myocardial infarction (AMI) has not been demonstrated.Objective
Our aim was to study the association between new-onset AF and long-term prognosis of nonagenarians who survive AMI.Methods
From a total of 96 patients aged ≥89 years admitted during a 5-year period, 64 (67 %) were discharged alive and are the focus of this study.Results
Mean age was 91.0 ± 2.0 years, and 39 patients (61 %) were women. During admission, 9 patients (14 %) presented new-onset AF, 51 (80 %) did not present AF, and 4 (6 %) had chronic AF. During follow-up (mean 2.3 ± 2.6 years; 6.6 ± 3.6 years in survivors), 58 patients (91 %) died, including the 9 patients with new-onset AF. Cumulative survival at 6, 12, 18, 24, and 30 months was 68.3 %, 57.2 %, 49.2 %, 47.6 %, and 31.8 %, respectively. The only two independent predictors of mortality in the multivariate analysis were age (hazard ratio [HR] 1.14; 95 % confidence interval [CI] 1.01–1.28; p = 0.04) and new-onset AF (HR 2.3; 95 % CI 1.1–4.8; p = 0.02).Conclusion
New-onset AF is a marker of poor prognosis in nonagenarians who survive AMI. 相似文献18.
The purpose of this work was to evaluate the potential of grewia gum (GG) as a suspending agent in pharmaceutical oral formulation using ibuprofen as model drug. Ibuprofen pediatric suspension (25 mg/5 mL) was formulated with grewia gum (0.5% w/v) as the suspending agent. Similar suspensions of Ibuprofen containing either sodium carboxymethylcellulose (Na-CMC) or hydroxymethylpropylcellulose (HPMC) were also produced. The suspensions were evaluated for ease of redispersion, sedimentation, rheological properties, and the effect of aging on the rheological properties at 25°C. The particle size and particle size distributions of the dispersed solute were determined. The redispersion time was 19, 11, and 0.5 min, respectively, for formulation containing Na-CMC, HPMC, and GG .The sedimentation volumes were 0.05, 0.05, and 0.125 mL, respectively, for Na-CMC, HPMC, and GG . Viscosities of suspensions at spindle speed of 25 rpm were of the order: GG > HPMC > Na-CMC when freshly prepared and of the order: HPMC > GG > Na-CMC within 6 months of storage. The particles size was 72.72, 73.82, 81.93, and 83.41 μm, respectively, for suspensions containing Na-CMC, ibuprofen alone, HPMC, and GG. Greatest hysteresis was observed in formulation containing HPMC. All the formulations were stable. It was our conclusion that the difference in the physicochemical properties of ibuprofen pediatric formulations was influenced more by the suspending agent used in the formulations than the drug. GG combined better redispersion with minimal changes in viscosity on storage compared to Na-CMC and HPMC as suspending agent. Thus GG may serve as a good suspending agent requiring no further aid in suspension redispersibility.KEY WORDS: grewia gum, oral pharmaceutical formulations, physicochemical properties, potential suspending agent 相似文献
19.
L. Ringoir J. W. Widdershoven S. S. Pedersen J. M. Keyzer V. J. Pop 《Netherlands heart journal》2014,22(5):234-239
Background
The prevalence and diagnostic value of heart failure symptoms in elderly primary care patients with hypertension is unknown.Aim
To assess the prevalence, sensitivity, specificity, positive and negative predictive value of symptoms in association with an abnormal echocardiogram.Design and setting
Cross-sectional screening study in five general practices in the south-east of the Netherlands.Method
Between June 2010 and January 2013, 591 primary care hypertension patients aged between 60 and 85 years were included, without known heart failure and not treated by a cardiologist. All patients underwent an echocardiogram and a structured interview including assessment of heart failure symptoms: shortness of breath, fatigue, oedema, cold extremities, and restless sleep.Results and conclusion
Restless sleep was reported by 25 %, cold extremities by 23 %, fatigue by 19 %, shortness of breath by 17 %, and oedema by 13 %. Oedema was the only symptom significantly associated with an abnormal echocardiogram (positive predictive value was 45 %, sensitivity 20 %, and specificity 90 %, OR 2.12; 95 % CI = 1.23–3.64), apart from higher age (OR 1.06; 95 % CI = 1.03–1.09), previous myocardial infarction (OR 3.00; 95 % CI = 1.28–7.03), and a systolic blood pressure of >160 mmHg (OR 1.62; 95 % CI = 1.08–2.41). Screening with echocardiography might be considered in patients with oedema. 相似文献20.
The effect of temperature and relative humidity (RH) on the stability of imidapril hydrochloride (IMD) in solid state was investigated. The main aim of this study was to determine the most appropriate conditions of storage and manufacture of IMD so that the efficiency of the technological process could be improved and its costs could be minimized. A reversed-phase high-performance liquid chromatography was validated and applied for the determination of IMD degradation samples under the following operating conditions: stationary phase, LiChrospher 100 RP-18 (size 5 μm) 250 × 4 mm I.D., and mobile phase, acetonitrile–methanol–phosphate buffer, pH 2.0, 0.035 mol L−1 (60:10:30 v/v/v). The effect of temperature on IMD degradation rate was analyzed under increased RH ∼76.4% (within temperature range of 70–90°C) and decreased RH ∼0% (within temperature range of 90–110°C). The influence of RH was investigated under 90°C within RH range of 25.0–76.4%. IMD degradation accords with autocatalytic reaction model, and RH has no influence on its mechanism yet it increases its rate. The reaction also accelerates under high temperatures and in the presence of IMD degradation product. Pure IMD is more stable than other structurally related angiotensin-converting enzyme inhibitors, such as enalapril maleate, but it still should be stored in tightly closed containers and protected from moisture and high temperatures.KEY WORDS: angiotensin-converting enzyme inhibitors, imidapril hydrochloride, RP-HPLC, stability, thermodynamics 相似文献