RESUMO
CONTEXT: Bacterial resistance to antibiotics is increasing and alternative antibacterial treatments like antimicrobial photodynamic therapy (aPDT) are needed. Curcumin is under investigation as a potential photosensitizer in aPDT. OBJECTIVE: The purpose of this study was to develop rapidly dissolving formulations of curcumin that could photoinactivate both Gram-positive and Gram-negative bacteria. MATERIALS AND METHODS: Curcumin solid dispersions with methyl-ß-cyclodextrin and hyaluronic acid (HA), hydroxypropyl methylcellulose (HPMC) or both HA and HPMC were prepared through lyophilization. The lyophilizates were characterized by curcumin drug load [% (w/w)], differential scanning calorimetry, photostability, thermal stability, their ability to form supersaturated solutions and by in vitro photoinactivation of Enterococcus faecalis and Escherichia coli. RESULTS AND DISCUSSION: The lyophilizates were amorphous solid dispersions with a curcumin drug load in the range of 1.4-5.5% (w/w) depending on the included polymer and the ratio between curcumin and the cyclodextrin. The lyophilizates were photolabile, but thermally stable and dissolved rapidly in contact with water to form supersaturated solutions. Selected lyophilizates demonstrated >log 6 reduction of colony forming units/ml of both E. faecalis and E. coli after exposure to low curcumin concentrations (0.5-10 µM) and blue light dose (11-16 J/cm(2)). The high drug load of the lyophilizates, rapid dissolution, ability to form relatively stable supersaturated solutions and the very high phototoxicity towards both E. faecalis and E. coli make these lyophilizates suitable for in vivo aPDT. CONCLUSIONS: This treatment with optimized curcumin formulations should be explored as an alternative to topical antibiotics in the treatment of wound infections.
Assuntos
Antibacterianos/administração & dosagem , Curcumina/administração & dosagem , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/administração & dosagem , Antibacterianos/química , Antibacterianos/farmacologia , Curcumina/química , Curcumina/farmacologia , Estabilidade de Medicamentos , Enterococcus faecalis/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Excipientes/química , Liofilização , Ácido Hialurônico/química , Derivados da Hipromelose/química , Fármacos Fotossensibilizantes/química , Fármacos Fotossensibilizantes/farmacologia , Solubilidade , beta-Ciclodextrinas/químicaRESUMO
The influence of four Pluronics block copolymers (i.e. F68, P123, F127, and L44) on the aggregation and solubilization of five structurally related meso-tetraphenyl porphyrin photosensitizers (PS) as model compounds for use in Photodynamic Therapy of cancer (PDT) was evaluated. Interactions between the PSs and Pluronics were studied at micromolar concentration by means of UV-Vis absorption spectrometry and by kinematic viscosity (υ) and osmolarity measurements at millimolar concentrations. Pluronic micelles were characterized by size and zeta potential (ζ) measurements. The morphology of selected PS-Pluronic assemblies was studied by atomic force microscopy (AFM). While hydrophobic 5,10,15,20-Tetrakis(4-hydroxyphenyl) porphine (THPP) seemed to be solubilized in the Pluronic micellar cores, amphiphilic di(monoethanolammonium) meso-tetraphenyl porphine disulphonate (TPPS2a) was likely bound to the micellar palisade layer. Hydrophilic PSs like 5,10,15,20-Tetrakis (4-trimethylaniliniumphenyl) porphine (TAPP) seemed to form complexes with Pluronic unimers and to be distributed among the micellar coronas. TPPS2a aggregated into a network which could be broken at Pluronic concentration [Formula: see text] cmc, but would reconstitute in the presence of tonicity adjusting agents, e.g. sodium chloride (NaCl) or glucose.
Assuntos
Mesoporfirinas/química , Fármacos Fotossensibilizantes/química , Poloxâmero/química , Tensoativos/química , Interações Hidrofóbicas e Hidrofílicas , Mesoporfirinas/metabolismo , Microscopia de Força Atômica/métodos , Tamanho da Partícula , Fármacos Fotossensibilizantes/metabolismo , Poloxâmero/metabolismo , Solubilidade , Tensoativos/metabolismoRESUMO
Phototoxic effect of curcumin supersaturated solutions toward pathogenic bacteria has already been demonstrated. However, to be useful in the clinical practice, a supersaturated solution needs to be physically and chemically stabile over the relevant time period. Poloxamer-based solid dispersions (SD) intended for ex tempore preparation of a supersaturated solution were designed to simultaneously facilitate dissolution and inhibit precipitation of curcumin in vitro. Due to the transformation of the crystalline compound to an amorphous form, as shown by X-ray powder diffraction, the desired concentration of curcumin could easily be achieved upon hydration of SDs. The efficiency of selected poloxamers (Pluronic® F-127, F-68 and P-123) as the precipitation inhibitors (PIs) and influence of an additional PI (polyethylene glycol 400, hydroxypropyl methylcellulose, and hyaluronic acid) on the physical stability of the solutions were examined by UV-Vis spectrophotometry. HPLC-PDA was employed to evaluate hydrolytic and photolytic stability of curcumin in the SD solutions. At sub-micellar concentrations, Pluronics® F-127 and P-123, but not F-68, delayed curcumin precipitation in aqueous media and protected the compound from hydrolytic degradation up to 24 h. Complete inactivation of Enterococcus faecalis was achieved after exposure to solutions of selected SDs at curcumin concentration ≥1 µM and the light dose of 9.4 J/cm2.
RESUMO
Alveld is a hepatogenous photosensitivity disorder in lambs. The aim of the study was to investigate if alveld affected lambs had a reduced capacity to handle oxidative stress induced from either endogenous and/or exogenous photosensitizers. Serum samples from alveld lambs (n=33) were compared to serum samples from control lambs (n=31) and exposed to a controlled amount of singlet oxygen ((1)O2). The sera from alveld lambs were found to have an impaired ability to deactivate reactive oxygen species (ROS) compared to control sera. A higher degree of initial hemolysis and a higher concentration of the exogenous photosensitizer phytoporphyrin (PP) were detected in alveld sera compared to the controls. The action spectrum for the formation of (1)O2 indicated that PP as well as the endogenous compound protoporphyrin IX (PP IX) may act as in vivo photosensitizers. A relatively high level of iron was detected in pooled serum from alveld lambs that showed a high degree of hemolysis. It was concluded that alveld photosensitivity is likely to be initiated by a photodynamic reaction involving PP and possibly also PP IX followed by a light-independent reaction involving hemoglobin-related products and catalysis by the Fenton reaction.
Assuntos
Oxidantes/sangue , Oxidantes/metabolismo , Estresse Oxidativo , Transtornos de Fotossensibilidade/veterinária , Doenças dos Ovinos/sangue , Doenças dos Ovinos/metabolismo , Ovinos , Animais , Hemólise , Minerais/metabolismo , Transtornos de Fotossensibilidade/sangue , Transtornos de Fotossensibilidade/imunologia , Transtornos de Fotossensibilidade/metabolismo , Protoporfirinas/metabolismo , Doenças dos Ovinos/imunologia , Oxigênio Singlete/metabolismoRESUMO
Curcumin is under investigation as a potential photosensitizer (PS) in antimicrobial photodynamic therapy (aPDT). The therapeutic potential of curcumin as a PS is limited by its low aqueous solubility, susceptibility to hydrolytic and photolytic degradation, and limited phototoxicity toward Gram negative (G-) bacteria. Supersaturated solutions of curcumin have demonstrated high phototoxicity toward several species of Gram positive (G+) bacteria as well as the G-Escherichia (E) coli. Thus, solid dispersions that can form supersaturated solutions of curcumin upon hydration may be beneficial in aPDT. In the present study, solid dispersions of curcumin have been prepared through lyophilization of concentrated solutions obtained from dissolution of hydroxypropyl-ß-cyclodextrin (HPßCD)-curcumin co-precipitates. Hydroxypropyl methylcellulose (HPMC) was added to curcumin solutions prior to lyophilization. The resulting lyophilizates were porous, amorphous and hydrated and dissolved rapidly in contact with a model physiological salt solution. The detected drug load of the lyophilizates was in the range 0.5-1.0% (w/w) and was dependent on the selected ratio between HPßCD and curcumin in the co-precipitate. The lyophilizate with the highest drug load could easily be dissolved in aqueous medium to form curcumin solutions of relevant concentrations for aPDT (i.e., 10µM). Selected solutions of the curcumin solid dispersions showed a pronounced decrease in curcumin concentration up to 90% after storage for 168h, which indicated that supersaturated curcumin solutions were initially formed upon dissolution of the lyophilizates. Both freshly prepared and 2days old solutions of one selected curcumin lyophilizate induced significant inactivation of E. coli (â¼1% bacterial survival) after exposure to a light dose of only 5J/cm(2).
Assuntos
Antibacterianos/administração & dosagem , Curcumina/administração & dosagem , Escherichia coli/efeitos dos fármacos , beta-Ciclodextrinas/química , 2-Hidroxipropil-beta-Ciclodextrina , Antibacterianos/química , Antibacterianos/farmacologia , Curcumina/química , Curcumina/farmacologia , Estabilidade de Medicamentos , Armazenamento de Medicamentos , Excipientes/química , Liofilização , Derivados da Hipromelose , Metilcelulose/análogos & derivados , Metilcelulose/química , Porosidade , Solubilidade , Fatores de TempoRESUMO
Samples of 10 µL of whole blood containing citalopram, loperamide, methadone, and sertraline as model substances were spotted on alginate and chitosan foams as sampling media. After drying and storage at room temperature, the punched out dried blood spot and the foam was dissolved in 300 µL of 1 mM HCl. With alginate foam as sampling medium, the analytes dissolved completely after 3 min. Enrichment and cleanup was performed with electromembrane extraction for 10 min. The analytes were collected in 21 µL of 10 mM formic acid as the acceptor phase, and the extracts were analyzed by liquid chromatography-mass spectrometry (LC-MS). Sample preparation of blood spots on commercial cards was also performed (Whatman FTA DMPK and Agilent Bond Elut DMS) using elution procedures recommended by the manufacturers. The recoveries obtained with the commercial cards were lower for most of the model analytes compared to the recoveries obtained with alginate and chitosan foams as sampling media. The procedure used for Agilent Bond Elut DMS showed higher recoveries than the procedure used for Whatman FTA DMPK-A, but the time needed for sample preparation was significantly longer (nearly 2 h). The stability of the model substances on the alginate foam was acceptable within 50 days of storage. The limit of quantification (LOQ) defined as S/N = 10, was 1.2, 5.5, 2.0, and 5.3 ng/mL for citalopram, loperamide, methadone, and sertraline, respectively. Linear calibration graphs were obtained in the range 17.5-560 ng/mL with r(2) values 0.983-0.995, and the relative standard deviations were below 20%.
Assuntos
Alginatos/química , Quitosana/química , Teste em Amostras de Sangue Seco/métodos , Técnicas Eletroquímicas/instrumentação , Membranas Artificiais , Preparações Farmacêuticas/sangue , Cromatografia Líquida/métodos , Desenho de Equipamento , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Humanos , Limite de Detecção , Espectrometria de Massas/métodosRESUMO
Solubilization and stabilization from rapid degradation by the use of nanocarriers are necessary to exploit curcumin's phototoxic potential towards pathogenic bacteria. However, maintenance of the phototoxicity requires a careful selection of type and amount of nanocarrier. The phototoxicity of an aqueous supersaturated curcumin solution without nanocarrier was compared to that of curcumin solubilized in polyethylene glycol 400 (PEG 400), Pluronic® F 127 (F 127) and hydroxypropyl-γ-cyclodextrin (HPγCD) on Staphylococcus (S.) epidermidis biofilms and suspensions. The nanocarriers stabilized the hydrophobic photosensitizer (PS) towards physical precipitation and hydrolytic degradation; however, photobleaching was pronounced (46-100% degradation) after irradiation with a dose of ≈ 9 J/cm(2) blue light depending on selected nanocarrier. Complete inactivation of S. epidermidis in suspension was achieved after exposure of ≈ 5 J/cm(2) combined with curcumin in 20% PEG 400 and 0.5% HPγCD and less than 1J/cm(2) light in case of a supersaturated curcumin solution. Curcumin in 1.5% F 127 induced phototoxicity towards bacterial biofilms; however, it was not phototoxic towards planktonic S. epidermidis. All curcumin preparations investigated demonstrated significant and similar phototoxicity towards biofilms (13-29% bacterial survival). A ≈ 9 J/cm(2) light dose was not sufficient to eradicate S. epidermidis biofilm completely under the current conditions.
Assuntos
Biofilmes/efeitos dos fármacos , Biofilmes/efeitos da radiação , Curcumina/química , Curcumina/farmacologia , Nanopartículas/química , Fármacos Fotossensibilizantes/farmacologia , Staphylococcus epidermidis/fisiologia , Antibacterianos/química , Antibacterianos/farmacologia , Portadores de Fármacos/química , Portadores de Fármacos/farmacologia , Interações Hidrofóbicas e Hidrofílicas , Luz , Fotodegradação , Fármacos Fotossensibilizantes/química , Plâncton/efeitos dos fármacos , Polietilenoglicóis/química , Polietilenos , Polipropilenos , Soluções/química , Staphylococcus epidermidis/efeitos dos fármacos , Staphylococcus epidermidis/efeitos da radiação , Suspensões/química , Suspensões/farmacologia , gama-Ciclodextrinas/químicaRESUMO
Curcumin loaded alginate foams are proposed for application in antimicrobial photodynamic therapy of infected wounds. The drug loaded foams were formulated to provide a burst release of the photosensitizer when hydrated. The foams remained intact after hydration and would be possible to remove from the wound prior to irradiation without causing any tissue damage. The characterization of the prepared foams showed that both curcumin loaded and unloaded foams hydrated within 1 min and absorbed from 12 to 16 times their dry weight of a model physiological fluid. Curcumin, the model photosensitizer, has an extremely low solubility in water and may aggregate in aqueous environment. Cyclodextrins (CDs) and polyethylene glycol 400 (PEG 400) were therefore selected as solubilizers of curcumin in the foams to provide a burst release of the photosensitizer. Exposure to the prepared foams in combination with visible light irradiation (â¼9.7 J/cm(2)) resulted in >6 log reduction of Entrococcus faecalis cells. However, curcumin mediated photokilling of Escherichia coli was ineffective when CDs were selected as solubilizer of curcumin in the foams. An 81% reduction in viable E. coli cells was detected after treatment with the foam containing PEG 400 as the only solubilizer of curcumin combined with visible light irradiation (â¼29 J/cm(2)).
Assuntos
Alginatos/química , Antibacterianos/farmacologia , Curcumina/análogos & derivados , Curcumina/farmacologia , Sistemas de Liberação de Medicamentos/métodos , Fármacos Fotossensibilizantes/farmacologia , Infecção dos Ferimentos/tratamento farmacológico , Antibacterianos/análise , Antibacterianos/química , Fenômenos Químicos , Química Farmacêutica , Curcumina/análise , Curcumina/química , Ciclodextrinas/química , Enterococcus faecalis/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Excipientes/química , Géis , Cinética , Luz , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/análise , Fármacos Fotossensibilizantes/química , Plastificantes/química , Polietilenoglicóis/química , Solubilidade , Água/análiseRESUMO
The aim of the present study was to incorporate a model water-insoluble photosensitizer, curcumin, in novel alginate foams, further to evaluate the suitability of the curcumin loaded foams in antimicrobial photodynamic therapy of infected wounds. Six foam formulations were prepared and characterized with respect to physical characteristics, in vitro release and storage- and photo-stability of curcumin. One formulation was sterilized (gamma-sterilization). The foams contained hydroxypropyl-beta-cyclodextrins or hydroxypropyl-gamma-cyclodextrins as solubilizers of curcumin. A reference foam without cyclodextrins was prepared with PEG 400 as the solubilizer. At a curcumin load of 0.153% (w/w), the water insoluble photosensitizer was uniformly distributed in the hydrophilic foams matrix. All foams were easy to handle, flexible and hydrated rapidly in a model physiological fluid. Release of curcumin in its monomeric form was demonstrated in vitro and found to be dependent on the type and amount of cyclodextrins in the formulation. Curcumin was stable during storage, but susceptible to photodegradation in the foams, especially when the formulations contain PEG 400 or hydroxypropyl-gamma-cyclodextrins. Curcumin did not degrade after gamma-sterilization, however a decrease in the in vitro release rate of curcumin and changes in the foams physical characteristics were detected.
Assuntos
Alginatos/química , Anti-Infecciosos/administração & dosagem , Curcumina/análogos & derivados , Curcumina/química , Fotoquimioterapia/métodos , Infecção dos Ferimentos/tratamento farmacológico , 2-Hidroxipropil-beta-Ciclodextrina , Absorção , Anti-Infecciosos/química , Química Farmacêutica , Cromatografia Líquida de Alta Pressão , Cor , Preparações de Ação Retardada , Sistemas de Liberação de Medicamentos , Estabilidade de Medicamentos , Excipientes , Cinética , Luz , Esterilização , beta-Ciclodextrinas , gama-CiclodextrinasRESUMO
BACKGROUND: The Norwegian Medicines Agency has since 2003 encouraged health professionals to report adverse events (AEs) related to generic substitution through the spontaneous reporting system. Goals of this study were to evaluate the quality of these reported AEs and to assess whether there were signals of altered efficacy or AEs related to substitution of such products. MATERIAL AND METHODS: The World Health Organisation's (WHO) tool for documentation grading was used to evaluate the AE reports. Signals of AEs were identified based on WHO's signal definition. RESULTS: 423 spontaneous reports concerning substitution of generic products were identified; 232 (55 %) of these reached documentation grade 1?-?3 and could be used to detect signals of AEs. The AEs were mostly common symptoms that also appear in the general population not treated with drugs. Only two of the 423 reports were classified as serious AEs. Signals of dizziness and muscle pain were identified after substitution of the original product Norvasc with the generic product Amlodipin Ratiopharm. Amlodipine was the substance associated with most AE reports; i.e. 79 (19 %) reports. INTERPRETATION: About half the spontaneous reports regarding substitution of generic products could be used for signal detection. The substitution of generics does not seem to represent a safety problem.