Silver Nanoparticles/Ibuprofen-Loaded Poly(l-lactide) Fibrous Membrane: Anti-Infection and Anti-Adhesion Effects

Infection caused by bacteria is one of the crucial risk factors for tendon adhesion formation. Silver nanoparticles (AgNP)-loaded physical barriers were reported to be effective in anti-infection and anti-adhesion. However, high silver load may lead to kidney and liver damages. This study was designed for Ibuprofen (IBU)-loaded poly(l-lactide) (PLLA) electrospun fibrous membranes containing a low dosage of Ag to evaluate its potential in maintaining suitable anti-infection and good anti-adhesion effects. The in vitro drug release study showed a sustained release of Ag ions and IBU from the membrane. Inferior adherence and proliferation of fibroblasts were found on the Ag4%–IBU4%-loaded PLLA electrospun fibrous membranes in comparison with pure PLLA and 4% Ag-loaded PLLA membranes. In the antibacterial test, all Ag-loaded PLLA electrospun fibrous membranes prevented the adhesion of Staphylococcus aureus and Staphylococcus epidermidis. Taken together, these results demonstrate that Ibuprofen is effective in enhancing the anti-adhesion and anti-proliferation effects of 4% Ag-loaded PLLA fibrous membrane. The medical potential of infection reduction and adhesion prevention of Ag4%–IBU4%-loaded PLLA electrospun fibrous membrane deserves to be further studied.     

布洛芬热分解及其动力学研究

通过布洛芬(ibuprofen)的热分解及其动力学研究,运用简单的热分解动力学方法进行计算分析,求出相关的活化能,指前因子和动力学参数。将布洛芬每个温度范围下的热分解过程分为3个阶段分别进行分析计算,发现每个阶段都满足一级反应方程。从而算出布洛芬热分解过程的活化能,指前因子和相关系数。通过对布洛芬热分解过程的研究,及对布洛芬TG和DTG曲线的研究,得出布洛芬在热分解过程中分为3个阶段,分别进行脱水,C-C键断裂和分子键断裂。并且随着升温速率的提高,布洛芬失重速率会逐渐趋向于温度升高的方向发展,即温度升高,布洛芬最大失重速率越大。     

辐射法制备布洛芬金属分子印迹聚合膜

以消炎镇痛药(S)-布洛芬与Cu2+配合物为模板分子,以甲基丙烯酸为功能单体,乙二醇二甲基丙烯酸酯为交联剂,聚砜膜为多孔支撑层,利用辐射引发聚合制备了Cu2+配位分子印迹复合膜。通过紫外光谱研究发现,(S)-布洛芬、Cu2+和甲基丙烯酸形成了配位比为1∶2∶2的3元配合物。通过扫描电镜及渗透实验发现聚砜基膜固含量为17%时,修饰后印迹膜形态及性能最好。同时,通过选择渗透实验发现,印迹膜对其手性对称物(R)-布洛芬及结构类似物酮洛芬渗透选择性较差。     

Synthesis and Evaluation of Novel Polyester-Ibuprofen Conjugates for Modified Drug Release

Ibuprofen was conjugated at different levels to a novel polyester, poly(glycerol-adipate-co-ω-pentadecalactone) (PGA-co-PL), via an ester linkage to form a prodrug. The conjugates were characterized by differential scanning calorimetry (DSC), nuclear magnetic resonance (NMR), infrared (IR), gel permeation chromatography (GPC), ultraviolet (UV), and high-performance liquid chromatography (HPLC). The conjugates had a molecular weight between 18 and 24 kDa, and there was a suppression of the free hydroxyl groups within the conjugated polymer. DSC scans showed a lowering of the melting point (T_m) when compared with the polyester alone and a difference in the number and area of T_m peaks. Drug release studies showed an initial burst release (13–18%) followed thereafter by very slow release (maximum 35% after 18 days). Continuous work may produce ester-linked conjugates that are sufficiently labile to allow for complete release of ibuprofen over the time period studied.     

β-TCP porous pellets as an orthopaedic drug delivery system: ibuprofen/carrier physicochemical interactions

Abstract

Calcium phosphate bone substitute materials can be loaded with active substances for in situ, targeted drug administration. In this study, porous β-TCP pellets were investigated as an anti-inflammatory drug carrier. Porous β-TCP pellets were impregnated with an ethanolic solution of ibuprofen. The effects of contact time and concentration of ibuprofen solution on drug adsorption were studied. The ibuprofen adsorption equilibrium time was found to be one hour. The adsorption isotherms fitted to the Freundlich model, suggesting that the interaction between ibuprofen and β-TCP is weak. The physicochemical characterizations of loaded pellets confirmed that the reversible physisorption of ibuprofen on β-TCP pellets is due to Van der Waals forces, and this property was associated with the 100% ibuprofen release.     

Simple and Sensitive HPLC Method with Fluorescence Detection for the Measurement of Ibuprofen in Rat Plasma: Application to a Long-Lasting Dosage Form

A simple and sensitive high-performance liquid chromatography (HPLC) assay applied to the measurement of ibuprofen in rat plasma has been developed. Two parameters have been investigated to improve ibuprofen detectability using fluorescence detection: variation of mobile phase pH and the use of β-cyclodextrin (β-CD). Increasing the pH value from 2.5 to 6.5 and adding 5 mM β-CD enhanced the fluorescence signal (λ_exc = 224 nm; λ_em = 290 nm) by 2.5 and 1.3-fold, respectively, when using standards. In the case of plasma samples, only pH variation significantly lowered detection and quantification limits, down to 10 and 35 ng/mL, respectively. Full selectivity was obtained with a single step for plasma treatment, that is, protein precipitation with acidified acetonitrile. The validated method was applied to a pharmacokinetic study of ibuprofen encapsulated in microspheres and subcutaneously administered to rats.     

Enhanced Dissolution of Ibuprofen Using Solid Dispersion with Polyethylene Glycol 20000

To improve its dissolution, ibuprofen solid dispersions (SDs) were prepared in a relatively easy and simple manner, characterized by scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR), and evaluated for solubility and in vitro drug release. Loss of individual surface properties during melting and re-solidification as revealed by SEM micrographs indicated the formation of effective SDs. Absence or shifting toward the lower melting temperature of the drug peak in SDs in DSC study indicated the possibilities of drug–polymer interactions. FTIR spectra showed the presence of drug crystalline in SDs. The effect of improved dissolution on the oral absorption of ibuprofen in rats was also studied. Quicker release of ibuprofen from SDs in rat intestine resulted in a significant increase in AUC and C_max, and a significant decrease in T_max over pure ibuprofen. Preliminary results from this study suggested that the preparation of fast dissolving ibuprofen SDs by low-temperature melting method using polyethylene glycol 20000 as a meltable hydrophilic polymer carrier could be a promising approach to improve solubility, dissolution, and absorption rate of ibuprofen.     

Adsorption of Ibuprofen and Atenolol at Trace Concentration on Activated Carbon

Abstract

Adsorption isotherms of atenolol and ibuprofen onto activated carbon (AC) at trace concentration in water (initial concentration, 80 μg/L – equilibrium concentration as low as 0.13 μg/L) are presented in this paper. Their adsorption was studied considering two ACs (F400 and Picabiol) showing different textural and chemical characteristics. Experiments were performed in buffered ultrapure water with and without humic acids to evaluate their influence on adsorption. It was found that adsorption was not in agreement with expectations based either on the log K_ow or log D values of the target compounds. Adsorption mechanisms were discussed and the experimental isotherms were modelled.     

Drug-Delivery By Ion-Exchnage. Part VII: Release of Acidic Drugs from Anionic Exchange Resinate Complexes

The loading and relase of ibuprofen, Ketoprofen and mefenamic acid from a range of strong anionic exchange resins, including cholestyramine, is decribed. Release rates into simulated gastric fluid increase with stirring speed up to 300 rpm and decrease as either the particle size of the resin beads of the degree of cross-linking increase. An increase in the temperature of loading enhances the capacity of the resin towards the drug and reduce its relase rate. Coating of the resing also enables suppression of drug release to be achieved. The samll particle size of cholestyramine enables a rapid relese of drug from the resin to be achieved. This rate is significantly greater than that obtained by monitoring dissolution from a drug-lactose dispersion and may indicate that ion-exchange technology may provide and opportunity to overcome poor dissolution characteristicsf for weekly ionic compounds.     

Enantioselective esterification of ibuprofen with ethanol as reactant and solvent catalyzed by immobilized lipase: experimental and molecular modeling aspects

BACKGROUND: In recent years enantioselective esterification of racemic ibuprofen performed in organic co‐solvent media such as isooctane and cyclohexane and catalyzed by lipases, has been proposed as an effective way to increase the concentration of S‐ibuprofen in the racemic mixture. In this contribution, the enantioselective enzymatic esterification of (R,S)‐ibuprofen with ethanol catalyzed by commercial Novozym 435 without the addition of a co‐solvent is thoroughly investigated. Experimental data are further analyzed considering the results of extensive molecular modeling calculations. RESULTS: The conversion of ibuprofen towards the ethyl esters and the enantiomeric excess towards S‐ibuprofen are greatly affected by the ethanol and water contents of the reaction media. The optimum conditions for the esterification of racemic ibuprofen in a batch‐type reactor were as follows: molar ratio of ethanol to ibuprofen = 7, 4.8% v/v of water, 160 mg of Novozym 435, 45 °C and 200 rpm. Under these conditions an enantiomeric excess of 54% and 63% of ibuprofen conversion were reached. CONCLUSIONS: Results showed that the reaction in excess of the esterifying alcohol in a system free of additional organic solvents is possible if the proper conditions are set. Molecular modeling calculations demonstrated that the formation of dead‐end compounds between the enzyme and ethanol/water may account for lipase inhibition at high concentrations of those compounds. Copyright © 2009 Society of Chemical Industry