Amphiphilogels as drug carriers: effects of drug incorporation on the gel and on the active drug

Amphiphilogels (a subset of organogels) are being studied as drug carriers in our laboratories. In this paper, the effects of drug incorporation on the drugs and the gels are discussed. Amphiphilogels were prepared by heating a mixture of the gelator (sorbitan monostearate or sorbitan monopalmitate) and the liquid (e.g. Tweens or liquid Spans) to form a solution/dispersion, which was cooled to the gel state. Drugs were dissolved by heating a mixture of the drug and the gel and cooling the resulting solution. Hydrophilic gels (composed of hydrophilic Tweens as the liquid) were more effective solvents than hydrophobic ones (composed of hydrophobic Span 20 or 80 liquids). The latter's solvent capacity could, however, be increased by the inclusion of co-solvents, such as propylene glycol and ethanol. Drug incorporation at 10% w/w did not cause any detrimental changes in gel stability, while the drug's release rate was dependent on its concentration and on the nature of the gel's liquid component (which influences drug solubility), but not on gelator concentration or on the method of drug incorporation. This study shows the importance of the nature of the gels' liquid component and the possibility of using hydrophilic amphiphilogels as solvents for poorly water-soluble drugs.

Effect of punch tip geometry and embossment on the punch tip adherence of a model ibuprofen formulation

The sticking of a model ibuprofen-lactose formulation with respect to compaction force, punch tip geometry and punch tip embossment was assessed. Compaction was performed at 10, 25 or 40 kN using an instrumented single-punch tablet press. Three sets of ‘normal’ concave punches were used to evaluate the influence of punch curvature and diameter. The punches were 10, 11 and 12 mm in diameter, respectively. The 10-mm punch was embossed with a letter ‘A’ logo to assess the influence of an embossment on sticking. Flat-faced punches (12.5 mm) were used for comparison with the concave tooling. Surface profiles (Taylor Hobson Talysurf 120) of the upper punch faces were obtained to evaluate the surface quality of the tooling used. Following compaction, ibuprofen attached to the upper punch face was quantified by spectroscopy. Increasing punch curvature from flat-faced punches to concave decreased sticking. Altering punch diameter of the concave punches had no effect on sticking when expressed as μg mm−2. The embossed letter ‘A’ logo increased sticking considerably owing to the probable concentration of shear stresses at the lateral faces of the embossed logo.

Effects of surface roughness and chrome plating of punch tips on the sticking tendencies of model ibuprofen formulations

The sticking of three model ibuprofen–lactose formulations with respect to compaction force and the surface quality of the upper punch were assessed. Compaction was performed at 10, 25 or 40 kN using an instrumented single-punch tablet press. Two sets of 12.5-mm flat-faced punches were used to evaluate the influence of surface quality. A third set of chrome-plated tooling was also used. Surface profiles (Taylor Hobson Talysurf 120) of the normal tooling upper punches indicated a large difference in quality. The punches were subsequently classified as old (Ra = 0.33 μm) or new (Ra = 0.04 μm) where Ra is the mean of all positive deviations from zero. Surface profiles of sample tablets were also obtained. Following compaction, ibuprofen attached to the face was quantified by spectroscopy. Punch surface roughness, compaction force and the blend composition were all significant factors contributing to sticking. Chrome plating of punch faces increased sticking at a low compaction force but decreased sticking at higher forces. Surface roughness of the tablets did not correlate with the corresponding data for sticking, indicating that this is not a suitable method of quantifying sticking.

Partitioning of nonsteroidal antiinflammatory drugs in lipid membranes: a molecular dynamics simulation study

Using the potential of mean constrained force method, molecular dynamics simulations with atomistic details were performed to examine the partitioning and nature of interactions of two nonsteroidal antiinflammatory drugs, namely aspirin and ibuprofen, in bilayers of dipalmitoylphosphatidylcholine. Two charge states (neutral and anionic) of the drugs were simulated to understand the effect of protonation or pH on drug partitioning. Both drugs, irrespective of their charge state, were found to have high partition coefficients in the lipid bilayer from water. However, the values and trends of the free energy change and the location of the minima in the bilayer are seen to be influenced by the drug structure and charge state. In the context of the transport of the drugs through the bilayer, the charged forms were found to permeate fully hydrated in contrast to the neutral forms that permeate unhydrated.

Oxidative transformation of micropollutants during municipal wastewater treatment: comparison of kinetic aspects of selective (chlorine, chlorine dioxide, ferrate VI, and ozone) and non-selective oxidants (hydroxyl radical)

Chemical oxidation processes have been widely applied to water treatment and may serve as a tool to minimize the release of micropollutants (e.g. pharmaceuticals and endocrine disruptors) from municipal wastewater effluents into the aquatic environment. The potential of several oxidants for the transformation of selected micropollutants such as atenolol, carbamazepine, 17 alpha-ethinylestradiol (EE2), ibuprofen, and sulfamethoxazole was assessed and compared. The oxidants include chlorine, chlorine dioxide, ferrate(VI), and ozone as selective oxidants versus hydroxyl radicals as non-selective oxidant. Second-order rate constants (k) for the reaction of each oxidant show that the selective oxidants react only with some electron-rich organic moieties (ERMs), such as phenols, anilines, olefins, and deprotonated-amines. In contrast, hydroxyl radicals show a nearly diffusion-controlled reactivity with almost all organic moieties (k>or=10(9)M(-1) s(-1)). Due to a competition for oxidants between a target micropollutant and wastewater matrix (i.e. effluent organic matter, EfOM), a higher reaction rate with a target micropollutant does not necessarily translate into more efficient transformation. For example, transformation efficiencies of EE2, a phenolic micropollutant, in a selected wastewater effluent at pH 8 varied only within a factor of 7 among the selective oxidants, even though the corresponding k for the reaction of each selective oxidant with EE2 varied over four orders of magnitude. In addition, for the selective oxidants, the competition disappears rapidly after the ERMs present in EfOM are consumed. In contrast, for hydroxyl radicals, the competition remains practically the same during the entire oxidation. Therefore, for a given oxidant dose, the selective oxidants were more efficient than hydroxyl radicals for transforming ERMs-containing micropollutants, while hydroxyl radicals are capable of transforming micropollutants even without ERMs. Besides EfOM, ammonia, nitrite, and bromide were found to affect the micropollutant transformation efficiency during chlorine or ozone treatment.

Degradation of the emerging contaminant ibuprofen in water by photo-Fenton

In this study the degradation of the worldwide Non-Steroidal Anti-Inflammatory Drug (NSAID) ibuprofen (IBP) by photo-Fenton reaction by use of solar artificial irradiation was carried out. Non-photocatalytic experiments (complex formation, photolysis and UV/Vis-H(2)O(2) oxidation) were executed to evaluate the isolated effects and additional differentiated degradation pathways of IBP. The solar photolysis cleavage of H(2)O(2) generates hydroxylated-IBP byproducts without mineralization. Fenton reaction, however promotes hydroxylation with a 10% contamination in form of a mineralization. In contrast photo-Fenton in addition promotes the decarboxylation of IBP and its total depletion is observed. In absence of H(2)O(2) a decrease of IBP was observed in the Fe(II)/UV-Vis process due to the complex formation between iron and the IBP-carboxylic moiety. The degradation pathway can be described as an interconnected and successive principal decarboxylation and hydroxylation steps. TOC depletion of 40% was observed in photo-Fenton degradation. The iron-IBP binding was the key-point of the decarboxylation pathway. Both decarboxylation and hydroxylation mechanisms, as individual or parallel process are responsible for IBP removal in Fenton and photo-Fenton systems. An increase in the biodegradability of the final effluent after photo-Fenton treatment was observed. Final BOD(5) of 25 mg L(-1) was reached in contrast to the initial BOD(5) shown by the untreated IBP solution (BOD(5)<1 mg L(-1)). The increase in the biodegradability of the photo-Fenton degradation byproducts opens the possibility for a complete remediation with a final post-biological treatment.

[Ibuprofen release preferences of medicinal products, the market share of excipients vement of a polymer]

On pharmaceutical market, beside technological variability of the forms of a drug with ibuprofen, there also occurs variability of chemical and crystallographic forms of ibuprofen itself. The above allows to use ibuprofen not only in the form of pure acid, but also forms of ibuprofen sodium salts or hydrophilic solubilized complexes of very good solubility in water. The above influences changeability of technological parameters measured with the use of methods of quality control being the pharmacopeal standard. On the basis of information collected in pharmacies, it can be also considered that pharmacological effect of identical forms of drugs with ibuprofen in the same dose is differently perceived by patients expecting comfort of the process of treatment, the result of which is to be effective. The above arguments induce undertaking studies on the estimation of differences occurring between particular market versions of the forms of a drug with ibuprofen.

Scanning probe microscopy method for nanosuspension stabilizer selection

An atomic force microscopy (AFM) method was successfully developed and utilized for investigating the interaction of polymeric stabilizers with ibuprofen to determine their suitability for the preparation and stabilization of ibuprofen nanosuspensions. Images obtained clearly showed that HPMC and HPC interacted strongly with the ibuprofen resulting in extensive surface adsorption, confirming their suitability for ibuprofen nanosuspension preparation. In addition, differences in the morphology of the adsorbed HPMC and HPC molecules were observed, which may be attributed to their variable degree of substitution. Consistent with their poor performance in stabilizing the ibuprofen nanosuspensions, images obtained with PVP and Poloxamer's depicted inadequate adsorption on the ibuprofen surface. Careful analysis of the AFM images and the ibuprofen crystal structure gave valuable insight into the success of top-down processing for the preparation of nanosuspensions as compared to bottom-up processing. On the basis of the relationship observed between nanosuspension stability and adsorption characteristics of specific polymers, such AFM studies can aid in the selection of suitable nanosuspension stabilizers. This method provides the basis for a scientific rationale for nanosuspension stabilizer selection rather than the trial and error method which is currently practiced.

Polymer-mesoporous silica materials templated with an oppositely charged surfactant/polymer system for drug delivery

In this paper, polymer-mesoporous silica nanoparticles have been synthesized by a dual-template technology. Cationic polymer quaternized poly[bis(2-chloroethyl)ether-alt-1,3-bis[3-(dimethylamino)propyl]urea] (PEPU) and anionic surfactant sodium dodecyl sulfate (SDS) were used to form a homogeneous comicelle system to induce mesoporous silica spherical nanoparticles with diameters of 50-180 nm. The formation mechanism was studied by transmission electron microscopy (TEM), which suggested that PEPU played a cotemplate role in the synthesis process, and no mesoporous structure was generated without it. After removing the anionic surfactant, SDS, by an ion-exchange method, the cationic polymer-mesoporous silica nanoparticles were obtained. Using the materials as the host and ibuprofen (IBU)/captopril (CapH(2)) as the model drugs, the system revealed well-sustained release profiles.

Mineralization enhancement of a recalcitrant pharmaceutical pollutant in water by advanced oxidation hybrid processes

Degradation of the biorecalcitrant pharmaceutical micropollutant ibuprofen (IBP) was carried out by means of several advanced oxidation hybrid configurations. TiO(2) photocatalysis, photo-Fenton and sonolysis - all of them under solar simulated illumination - were tested in the hybrid systems: sonophoto-Fenton (FS), sonophotocatalysis (TS) and TiO(2)/Fe(2+)/sonolysis (TFS). In the case of the sonophoto-Fenton process, the IBP degradation (95%) and mineralization (60%) were attained with photo-Fenton (FH). The presence of ultrasonic irradiation slightly improves the iron catalytic activity. On the other hand, total removal of IBP and elimination of more than 50% of dissolved organic carbon (DOC) were observed by photocatalysis with TiO(2) in the presence of ultrasound irradiation (TS). In contrast only 26% of mineralization was observed by photocatalysis with H(2)O(2) (TH) in the absence of ultrasound irradiation. Additional results showed that, in the TFS system, 92% of DOC removal and complete degradation of IBP were obtained within 240 min of treatment. The advanced oxidation hybrid systems seems to be a promising alternative for full elimination/mineralization for the recalcitrant micro-contaminant IBP.

Molecular recognition in Mn-catalyzed C-H oxidation. Reaction mechanism and origin of selectivity from a DFT perspective

Experimental studies have shown that the C-H oxidation of Ibuprofen and methylcyclohexane acetic acid can be carried out with high selectivities using [(terpy')Mn(OH(2))(mu-O)(2)Mn(OH(2))(terpy')](3+) as catalyst, where terpy' is a terpyridine ligand functionalized with a phenylene linker and a Kemp's triacid serving to recognize the reactant via H-bonding. Experiments, described here, suggest that the sulfate counter anion, present in stoichiometric amounts, coordinates to manganese in place of water. DFT calculations have been carried out using [(terpy')Mn(O)(mu-O)(2)Mn(SO(4))(terpy')](+) as a model catalyst, to analyze the origin of selectivity and its relation to molecular recognition, as well as the mechanism of catalyst inhibition by tert-butyl benzoic acid. The calculations show that a number of spin states, all having radical oxygen character, are energetically accessible. All these spin states promote C-H oxidation via a rebound mechanism. The catalyst recognizes the substrate by a double H bond. This interaction orients the substrate inducing highly selective C-H oxidation. The double hydrogen bond stabilizes the reactant, the transition state and the product to the same extent. Consequently, the reaction occurs at lower energy than without molecular recognition. The association of the catalyst with tert-butyl benzoic acid is shown to shield the access of unbound substrate to the reactive oxo site, hence preventing non-selective hydroxylation. It is shown that the two recognition sites of the catalyst can be used in a cooperative manner to control the access to the reactive centre.

Layer-by-layer deposition of polymeric microgel films on surgical sutures for loading and release of ibuprofen

Surgical sutures capable of drug loading and sustained release are important in wound healing applications. In this work, a facile way to incorporate anti-inflammatory drug of ibuprofen in surgical sutures has been established. First, surgical sutures were deposited with multilayer films containing microgels of chemically cross-linked poly(allylamine hydrochloride) (PAH) and dextran (named PAH-D) by layer-by-layer deposition of PAH-D and hyaloplasm acid (HA). Ibuprofen was then incorporated in the PAH-D/HA films to obtain ibuprofen-loaded sutures. Ibuprofen incorporated in the surgical sutures can be released in 0.9% normal saline in a sustainable way. The successful incorporation of ibuprofen in surgical sutures depends largely on PAH-D microgels, which can deposit directly on the hydrophobic surgical sutures without any surface modification and load ibuprofen based on electrostatic interaction between them. The present study provides a facile and generally applicable way to incorporate drugs in surgical sutures that is highly useful to accelerate the healing of cuts and wounds.

Carboxyl enriched monodisperse porous Fe3O4 nanoparticles with extraordinary sustained-release property

Carboxyl-enriched monodisperse porous Fe3O4 nanoparticles with diameters of about 85-nm have been synthesized via a simple hydrothermal method. The porous structure of the product is confirmed further by transmission electron microscopy (TEM) observation and nitrogen sorption measurement with a Brunauer-Emmett-Teller (BET) surface area about 36.61 m2/g. An IR spectrum of the sample identifies that abundant carboxylate groups are formed on the surface of the nanoparticles as well as the pore surface. Because of the confined effect of the nanochannels in the nanoparticles and carboxyl-functionalized Fe3O4 nanoparticles, and the strong interaction between ibuprofen and COO-, as-prepared porous nanoparticles show a more extraordinary sustained-release property than that of hollow silica nanoparticles in vitro. This result suggests that as-prepared porous nanoparticles can also be used for the targeted delivery of other aromatic acid drugs.

Stationary cuvette: a new approach to obtaining analytical curves by UV-VIS spectrophotometry

BACKGROUND

Investigations in the field of pharmaceutical analysis and quality control of medicines require analytical procedures that achieve suitable performance. An analytical curve is one of the most important steps in the chemical analysis presenting a direct relationship to features such as linearity.

OBJECTIVE

This study has the aim of developing a new methodology, the stationary cuvette, to derive analytical curves by spectroscopy for drug analysis.

METHODOLOGY

The method consists basically of the use of a cuvette with a path length of 10 cm, containing a constant volume of solvent in which increasing amounts of a stock solution of the sample are added, droplet by droplet. After each addition, the cuvette is stirred and the absorbance is measured. This procedure was compared with the currently used methodology, which requires a labour-intensive dilution process, and possible sources of variation between them were evaluated.

RESULTS

The results demonstrated that the proposed technique presented high sensitivity and similar reproducibility compared with the conventional methodology. In addition, a number of advantages were observed, such as user-friendliness, cost-effectiveness, accuracy, precision and robustness.

CONCLUSION

The stationary cuvette approach may be considered to be an appropriate alternative to derive analytical curves for analysing drug content in raw materials and medicines through UV-VIS spectrophotometry.

PFGSE-NMR study of pH-triggered behavior in pluronic-ibuprofen solutions

The effect of drug addition and pH variation on Pluronic copolymer solutions has been investigated using pulsed-field gradient (PFG) NMR. Addition of ibuprofen to Pluronic P104 in solution reduced the overall pH from 7.5 to 4.5, as well as promoting micellization; a substantial increase in the hydrodynamic radius of the micelles, from 57.7 to 102.3 A was observed, along with an increase in the fraction of polymer micellized. The aggregation behavior was attributed primarily to the presence of ibuprofen, rather than the reduction in pH observed, since the micellization of P104 alone was not found to be significantly altered by pH changes in the region of interest. Conversely, for the P104 solutions containing ibuprofen, a strong pH-dependence was observed when raising the pH above the pK(a) of ibuprofen. The data obtained showed that, above pH 4.5, ibuprofen is gradually released from the micelles as a result of its improved solubility, leading to a reduction in the polymer aggregation toward that observed before the addition of ibuprofen.

Pluronic triblock copolymer systems and their interactions with Ibuprofen

Small-angle neutron scattering and pulsed-field gradient stimulated-echo nuclear magnetic resonance (NMR) have been used to study the structural characteristics of aqueous Pluronic solutions. In particular, changes in the micellar structure upon addition of ibuprofen to the solutions and altering the temperature have been investigated. Increases in temperature and ibuprofen concentration both appear to favor micellization, with increases observed in the aggregation number, fraction of polymer micellized, and core radius of the micelle, along with a decrease in the volume fraction of the solvent in the core. At high drug concentrations and/or temperatures, micelles of the more hydrophobic Pluronics scatter neutrons strongly at low Q, indicating attractive interactions between micelles or a change in the shape of the aggregates. The addition of ibuprofen to Pluronic P104 has also been found to reduce the critical micellization temperature from approximately 20 degrees C to below 13 degrees C. The hydrophobicity of the Pluronic, quantity of ibuprofen present, and temperature of the solution all seem to have a strong influence on the extent and nature of aggregation observed.

Self-assembly of ibuprofen and bovine serum albumin-dextran conjugates leading to effective loading of the drug

A simple and green process of simultaneous formation of albumin nanoparticles and encapsulation of hydrophobic drugs in aqueous solution was developed. Bovine serum albumin (BSA)-dextran conjugates were prepared through the Maillard reaction. Ibuprofen was used as a drug model. The solubility of protonated ibuprofen decreases, and then precipitation occurs when the pH of saturated ibuprofen solution is changed from alkali to acidic value. In the presence of the conjugates, a binding of ibuprofen with BSA through hydrophobic and electrostatic interactions can suppress the precipitation of ibuprofen. After a heat treatment, the gelation of BSA results in the formation of nanoparticles and fixing of the ibuprofen in the core. The nanoparticles were characterized with dynamic and static light scattering, zeta-potential, and transmission electron microscopy. The nanoparticles are of spherical shape having a hydrodynamic diameter of about 70 nm. As much as 0.7 unit weight of ibuprofen can be loaded into one unit weight of the conjugates. The dextran conjugated to BSA stabilizes the nanoparticles in aqueous solution.

Determination of the physical state of drug molecules in mesoporous silicon with different surface chemistries

Mesoporous silicon microparticles with three various surface chemistries and eight different average pore diameters for each surface modification, ranging from 11 to 75 nm, were loaded with ibuprofen. The loaded batches were characterized using thermal analysis and nitrogen sorption. Three thermodynamically different states of ibuprofen were found in the samples: a crystalline state outside the pores, a crystalline state inside the pores, and a disordered state inside the pores. Both the crystalline and disordered ibuprofen were found in the pores in all of the batches. Crystalline ibuprofen outside the pores was only found in two batches and in negligible amounts. The results supported the assumption that there is a layer of disordered ibuprofen adjacent to the pore wall (i.e., delta layer), in which the thickness is not strongly depending upon the pore size. The thickness of the disordered layer varied depending upon the surface chemistry of the pore wall and was 1.2, 1.5, and 2.0 nm for hydrogen-terminated, thermally oxidized, and thermally carbonized surfaces, respectively. The method gave detailed information on the physical state of ibuprofen in the batches. It can be used with any drug compound that is able to form crystals inside the mesopores and can be a useful tool in determining the optimal surface chemistry and pore size of a mesoporous drug-carrier material.

A retention-time-shift-tolerant background subtraction and noise reduction algorithm (BgS-NoRA) for extraction of drug metabolites in liquid chromatography/mass spectrometry data from biological matrices

A retention-time-shift-tolerant background subtraction and noise reduction algorithm (BgS-NoRA) is implemented using the statistical programming language R to remove non-drug-related ion signals from accurate mass liquid chromatography/mass spectrometry (LC/MS) data. The background-subtraction part of the algorithm is similar to a previously published procedure (Zhang H and Yang Y. J. Mass Spectrom. 2008, 43: 1181-1190). The noise reduction algorithm (NoRA) is an add-on feature to help further clean up the residual matrix ion noises after background subtraction. It functions by removing ion signals that are not consistent across many adjacent scans. The effectiveness of BgS-NoRA was examined in biological matrices by spiking blank plasma extract, bile and urine with diclofenac and ibuprofen that have been pre-metabolized by microsomal incubation. Efficient removal of background ions permitted the detection of drug-related ions in in vivo samples (plasma, bile, urine and feces) obtained from rats orally dosed with (14)C-loratadine with minimal interference. Results from these experiments demonstrate that BgS-NoRA is more effective in removing analyte-unrelated ions than background subtraction alone. NoRA is shown to be particularly effective in the early retention region for urine samples and middle retention region for bile samples, where the matrix ion signals still dominate the total ion chromatograms (TICs) after background subtraction. In most cases, the TICs after BgS-NoRA are in excellent qualitative correlation to the radiochromatograms. BgS-NoRA will be a very useful tool in metabolite detection and identification work, especially in first-in-human (FIH) studies and multiple dose toxicology studies where non-radio-labeled drugs are administered. Data from these types of studies are critical to meet the latest FDA guidance on Metabolite in Safety Testing (MIST).

In vitro genotoxic assessment of xenobiotic diacylglycerols in an in vitro micronucleus assay

Xenobiotic diacylglycerols (DG) may induce pathological disorders by causing abnormal chromosomal segregation, which could be aneuploid. In this study, seven xenobiotic-diacylglycerols (four of drug origin and three of pesticide origin) were evaluated for their ability to induce aneuploidy in mammalian cultures using in vitro cytokinesis blocked micronucleus (CBMN) assay coupled with kinetochore labeling and interphase fluorescent in situ hybridization. Out of seven xeno-DGs, two (ibuprofen-DG and fenbufen-DG) induced statistically significant (P < 0.001) and dose-dependent increase in micronucleus induction, but this apparent micronucleus induction was very weak in case of fenbufen-DG. These MN were produced predominantly by aneugenic and clastogenic mechanisms, respectively, confirmed by immunofluorescent labeling of kinetochores. Fluorescent in situ hybridization analysis revealed that ibuprofen-DG induced significantly higher nondisjunction for chromosomes 10, 17, and 18. Other xenobiotic diacylglycerols (indomethacin-DG, salicylic acid-DG, 4-(2-methyl-4-chlorophenoxy) butanoic acid-DG (MCPB-DG), 2-(2-methyl-4-chlorophenoxy) propanoic acid-DG (MCPP-DG) and 2-(4-dichlorophenoxy)-butanoic acid-DG (2,4 DB-DG) did not induce micronuclei, but the concentrations tested did not reach levels that caused the marked growth suppression typically required for testing for regulatory testing purposes. However, the levels of growth suppression achieved were similar to that seen with ibuprofen-DG, which was positive. This study shows that xeno-DGs, which have been neglected in the past for their possible link to any pathological disorders, need serious assessment of their mutagenic potential.

Assessment of the pharmaceutical active compounds removal in wastewater treatment systems at enantiomeric level. Ibuprofen and naproxen

The enantioselective degradation of ibuprofen and naproxen enantiomers was evaluated in five different wastewater treatment systems, including three constructed wetlands (vertical- and horizontal-flow configurations), a sand filter and an activated sludge wastewater treatment plant. In addition, injection experiments were carried out with racemic ibuprofen at microcosm- and pilot-scale constructed wetlands. Ibuprofen and naproxen have an asymmetric carbon atom and, consequently, two enantiomeric forms (i.e. S and R). The enantiomeric fraction (EF=S/(S+R)) in the raw sewage and effluents of various wastewater treatments were found to be compound-dependent (i.e. ibuprofen: EF(influent)=0.73-0.90, EF(effluent)=0.60-0.76; naproxen: EF(influent)=0.88-0.90, EF(effluent)=0.71-0.86). Of the two chiral pharmaceuticals, naproxen was the only one whose effluent EF correlated with its removal efficiency (p<0.05). The lack of correlation found for ibuprofen was attributable to the fact that its enantioselective degradation kinetics were different under prevailing aerobic and anaerobic conditions. Injection experiments of ibuprofen in constructed wetlands at microcosm and pilot-scale followed similar trends. Hence, under prevailing aerobic conditions, S-ibuprofen degraded faster than R-ibuprofen, whereas under prevailing anaerobic conditions, the degradation was not enantioselective. In summary, the naproxen EF measurements in wastewater effluents show that naproxen is a suitable alternative for evaluating the removal efficiency of treatment systems because its enantioselective degradation is similar under prevailing aerobic and anaerobic conditions.

Waste-derived activated carbons for removal of ibuprofen from solution: role of surface chemistry and pore structure

The removal of a widespread used drug (i.e., ibuprofen) from water was investigated using high valuable carbon adsorbents obtained from chemical and physical activation of a bioresource (cork) and a municipal waste (plastic). The waste-derived carbons outperformed the adsorption capacity of commercial carbonaceous adsorbents due to their adequate features for the removal of the targeted compound. Regarding the adsorption mechanism, the results obtained point out that ibuprofen retention is favored in activated carbons with basic surface properties. On the other hand, the textural features also play an important role; the presence of a transport pores network (i.e., mesopores) is crucial to ensure the accessibility to the inner porosity, and the microporosity must be large enough to accommodate the ibuprofen molecule. Specifically, adsorbents with a large fraction of ultramicropores (pore widths <0.7 nm) are not adequate to effectively remove ibuprofen.

Oral fast-dissolving drug delivery membranes prepared from electrospun polyvinylpyrrolidone ultrafine fibers

Oral fast-dissolving drug delivery membranes (FDMs) for poorly water-soluble drugs were prepared via electrospinning technology with ibuprofen as the model drug and polyvinylpyrrolidone (PVP) K30 as the filament-forming polymer and drug carrier. Results from differential scanning calorimetry, x-ray diffraction, and morphological observations demonstrated that ibuprofen was distributed in the ultrafine fibers in the form of nanosolid dispersions and the physical status of drug was an amorphous or molecular form, different from that of the pure drug and a physical mixture of PVP and ibuprofen. Fourier-transform infrared spectroscopy results illustrated that the main interactions between PVP and ibuprofen were mediated through hydrogen bonding. Pharmacotechnical tests showed that FDMs with different drug contents had almost the same wetting and disintegrating times, about 15 and 8 s, respectively, but significantly different drug dissolution rates due to the different physical status of the drug and the different drug-release-controlled mechanisms. 84.9% and 58.7% of ibuprofen was released in the first 20 s for FDMs with a drug-to-PVP ratio of 1:4 and 1:2, respectively. Electrospun ultrafine fibers have the potential to be used as solid dispersions to improve the dissolution profiles of poorly water-soluble drugs or as oral fast disintegrating drug delivery systems.

[Dry plant extracts in the prescription of dental hydrogels with Carbopol 971P]

The study assumption was to work out a prescription for dental anti-inflammatory hydrogel on Carbopol 971P base. Dry plant extracts (sage, horsetail) and nonsteroidal anti-inflammatory drug (sodium ibuprofen) were introduced into the prescription of a model hydrogel. The aim of the study was to estimate pharmaceutical availability of the applied therapeutic agents and to test their effect on physicochemical properties of the produced form of a drug. The physicochemical parameters of the produced preparation were tested. Viscosity tests were performed using cone-plate digital rheometer. Extensometric method was used to test extensibility. pH measurements were performed by direct immersing the electrode connected with pH-meter into the hydrogel samples of uniform mass. Pharmaceutical availability of therapeutic agents contained in hydrogel (active components of plant extracts, sodium ibuprofen) was estimated. The rate of the process of mass exchange was tested by spectrophotometric method determining the quantity of therapeutic agents diffusing into acceptor fluid at the same time intervals. Sodium ibuprofen is better released from the hydrogel containing horsetail extract (815.5 c.u.) than from the hydrogel of parallel prescription containing sage extract (640.8 c.u.). Hydrogels containing dry extract from horsetail have greater extensibility and lower structural viscosity as well as the value of yield stress than equivalent hydrogels containing sage extract. Introduction of sodium ibuprofen into the prescription of hydrogels with plant extracts modifies rheological parameters (greater extensibility, lower viscosity of the preparation). The tests of the kinetics of therapeutic agents release demonstrated that the presence of sodium ibuprofen in the prescription of hydrogels exerts an influence on the decrease of the effectiveness of the release of active substances contained in these extracts.