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1
Surface modification of an intraocular lens material by plasma-assisted grafting with 2-hydroxyethyl methacrylate (HEMA), for controlled release of moxifloxacin
Publicationby Vieira, Ana PaulaOther Authors: Pimenta, Andreia; Silva, Diana; Gil, Maria; Alves, Patrícia; Coimbra, Patrícia et al.Origin: uBibliorumEndophthalmitis, an inflammation of the eye due to perioperative infection, may occur after cataract surgery. Intraocular lenses (IOLs) loaded with an antibiotic have been proposed as an alternative to the conventional postoperative endophthalmitis prophylaxis, since the antibiotic is delivered directly to the target site. In this work, an IOL-based antibiotic releasing system was prepared from a copolymer used in the production of IOLs and a fluoroquinolone used in endophthalmitis prophylaxis (moxifloxacin, MFX). Argon plasma-assisted grafting with 2-hydroxyethyl methacrylate (HEMA) in the presence of MFX was the approach selected for surface modification, with MFX loaded both by entrapment in the grafted polyHEMA coating and by soaking. Surface and bulk properties were evaluated before and after surface modification and the MFX release profiles were obtained both in batch mode (sink conditions) and under hydrodynamic conditions, employing a purpose-built microfluidic cell, which simulated the hydrodynamic conditions around the eye lens. The effect of storage on the release profile of the best system was also assessed. The best system released MFX for ca. 15 days above the minimum inhibitory concentration for Staphylococcus aureus and Staphylococcus epidermidis. The released MFX showed antimicrobial activity against these bacteria and was non-cytotoxic against corneal endothelial cells. -
2
Dual drug delivery from hydrophobic and hydrophilic intraocular lenses: in-vitro and in-vivo studies
Publicationby Topete, AnaOther Authors: Tang, Junmei; Ding, Xiaoxu; Filipe, Helena P; Saraiva, Jorge A.; Serro, Ana Paula et al.Posterior capsule opacification (PCO) still remains the most frequent long term complication after cataract surgery, while endophthalmitis is rare but severe and should be prevented at all cost. Intraocular lenses (IOLs) with different designs (eg. edge and body-haptics angle) and materials (acrylic hydrophobic and acrylic hydrophilic surfaces) have been studied to reduce PCO. For the prevention of endophthalmitis, intracameral injection followed or not by topical treatment with antibiotics and anti-inflammatories are usually prescribed. The objective of this work was to investigate the use of IOLs as controlled release platforms of two drugs, the antibiotic moxifloxacin (MXF) and the anti-inflammatory ketorolac (KTL) that could advantageously substitute the usual treatment. Two types of IOLs were chosen, hydrophobic and hydrophilic. Hydrophobic IOLs have shown better results in the prevention of PCO because they adhere better to the posterior capsular bag, while hydrophilic IOLs are advised in the case of patients with uveitis, glaucoma or diabetes. The IOLs were loaded with MXF + KTL and sterilized by high hydrostatic pressure. Both IOLs reduced the tendency for adhesion of LECs. In vivo tests were done to compare the concentration of the drugs in the aqueous humor obtained after eye drops administration and drug-loaded IOLs implantation. The developed IOLs were able to release MXF and KTL at therapeutic levels, in a sustained way, which contrasts with the eye drops prophylaxis. No PCO signs were detected and histological analyses demonstrated biocompatibility of these devices. -
3
Immunomodulatory Effects and Protection in Sepsis by the Antibiotic Moxifloxacin
Publicationby Velho, TROther Authors: Raquel, H; Figueiredo, N; Neves-Costa, A; Pedroso, D; Santos, I et al.Origin: Lusíadas SaúdeSepsis is a leading cause of death in Intensive Care Units. Despite its prevalence, sepsis remains insufficiently understood, with no substantial qualitative improvements in its treatment in the past decades. Immunomodulatory agents may hold promise, given the significance of TNF-α and IL-1β as sepsis mediators. This study examines the immunomodulatory effects of moxifloxacin, a fluoroquinolone utilized in clinical practice. THP1 cells were treated in vitro with either PBS or moxifloxacin and subsequently challenged with lipopolysaccharide (LPS) or E. coli. C57BL/6 mice received intraperitoneal injections of LPS or underwent cecal ligation and puncture (CLP), followed by treatment with PBS, moxifloxacin, meropenem or epirubicin. Atm-/- mice underwent CLP and were treated with either PBS or moxifloxacin. Cytokine and organ lesion markers were quantified via ELISA, colony-forming units were assessed from mouse blood samples, and DNA damage was evaluated using a comet assay. Moxifloxacin inhibits the secretion of TNF-α and IL-1β in THP1 cells stimulated with LPS or E. coli. Intraperitoneal administration of moxifloxacin significantly increased the survival rate of mice with severe sepsis by 80% (p < 0.001), significantly reducing the plasma levels of cytokines and organ lesion markers. Notably, moxifloxacin exhibited no DNA damage in the comet assay, and Atm-/- mice were similarly protected following CLP, boasting an overall survival rate of 60% compared to their PBS-treated counterparts (p = 0.003). Moxifloxacin is an immunomodulatory agent, reducing TNF-α and IL-1β levels in immune cells stimulated with LPS and E. coli. Furthermore, moxifloxacin is also protective in an animal model of sepsis, leading to a significant reduction in cytokines and organ lesion markers. These effects appear unrelated to its antimicrobial activity or induction of DNA damage. -
4
Immunomodulatory effects and protection of moxifloxacin in sepsis
Publicationby Velho, Tiago RodriguesSepsis is a complex syndrome that results from a harmful systemic inflammatory response to infection. It is the leading cause of death in Intensive Care Units, excluding neurotrauma, and the third most important cause of death in the hospital. However, it remains poorly understood, and in fact, in the past decades there have been no substantial advances in the treatment of this condition. As TNF-α and IL-1β are two important initial mediators of sepsis, immunomodulatory agents may be useful in the treatment of sepsis. Here we show that moxifloxacin, a fourth-generation fluoroquinolone with a broad antibacterial spectrum, has immunodulatory effects both in an in vitro assay and in a mice model of sepsis. Moxifloxacin protects against severe sepsis in mice, reducing the levels of cytokines and organ lesion markers. Moreover, our findings demonstrate that its actions are not due to its antibacterial effect and that its interaction with topoisomerase II or IV may not be relevant for the observed effects. The molecular mechanisms that explain its immunomodulatory effects remain unknown, and are certainly an interesting topic for future studies. -
5
Development of membranes containing a controlled drug release system for ophthalmological applications
Publicationby Pinão, Sílvia Raquel NevesA eficácia da administração de um fármaco depende muito da sua concentração no local a ser tratado, durante um período de tempo adequado. Hoje em dia, o método de administração de fármacos mais utilizado para muitas doenças oculares é a aplicação de colírios, embora este método seja muito ineficiente e pode levar a efeitos secundários indesejáveis. O uso de lentes de contacto como sistemas de libertação de fármacos é uma alternativa promissora, devido ao contacto prolongado com a superfície do olho, ao alto grau de conforto e à biocompatibilidade.Neste trabalho, foram desenvolvidas membranas para serem usadas como sistemas de libertação controlada de um antibiótico (moxifloxacina, MFX), partindo de quitosano e de poliacrilatos e utilizando os métodos de evaporação do solvente e de polimerização na massa, respectivamente. Três das membranas desenvolvidas foram seleccionadas para os estudos subsequentes e para carregamento de MFX: uma membrana à base de quitosano, contendo, também, gelatina, reticulada com glioxal e plastificada com poli(álcool vinílico) e poli(etileno glicol) (CBM 16) e duas membranas à base de poliacrilatos, uma preparada a partir de metacrilato de metilo (MMA), metacrilato de octadecilo (ODMA) e acrilato de 2-etil-hexilo (EHA) (ABM 4) e outra preparada a partir de MMA, ODMA, EHA e ácido metacrílico (MAA) (ABM 5). Também foi estudada a influência de uma modificação da membrana ABM 4 de três maneiras diferentes, por copolimerização enxerto utilizando radiação gama: (i) enxerto com metacrilato de 2-hidroxietilo (HEMA) empregando uma dose de radiação de 25 kGy (ABM 4.1); (ii) enxerto com metacrilato de N,N-dimetilaminoetilo (DMAEMA), empregando doses de radiação 25 e 15 kGy (ABM 4.2 e ABM 4.4, respectivamente) e (iii) enxerto com DMAEMA na presença de MFX, empregando uma dose de radiação de 15 kGy, com e sem um carregamento subsequente por soaking numa solução de MFX (ABM 4.3).Foi determinada a capacidade de inchaço, o ângulo de contacto com a água, os espectros vibracionais no infravermelho e a citotoxicidade das membranas. Os resultados mostraram que a membrana ABM 5 foi a que apresentou características mais semelhantes às de lentes de contacto comerciais.Introduziu-se MFX nas membranas mais promissoras quer por oclusão (O), quer por imersão (soaking; S), de modo a preparar sistemas de libertação controlada. Os resultados da libertação de MFX permitiram concluir que as membranas ABM 4 e ABM 5 carregadas por oclusão (ABM 4 – O; ABM 5 – O), foram as que apresentaram um maior tempo de libertação de fármaco (3 dias). Relativamente às membranas modificadas por enxerto empregando radiação gama e carregadas por imersão, concluiu-se que a membrana com o melhor resultado foi a ABM 4.4 - S, com 2 dias de libertação de fármaco e que a modificação por enxerto melhorou a libertação de fármaco quando este foi introduzido por imersão, mas piorou-a quando o fármaco foi introduzido por oclusão. -
6
The effects of addition of functional monomers and molecular imprinting on dual drug release from intraocular lens material
Publicationby Topete, AnaOther Authors: Barahona, Isabel; Santos, Luís F.; Pinto, Carlos A.; Saraiva, Jorge A.; Serro, Ana Paula et al.Although cataract surgery is considered a safe procedure, post-surgery complications such as endophthalmitis and ocular inflammation, may occur. To prevent this, antibiotics and anti-inflammatories are prescribed in the form of eye drops during the post-operatory period, but they lead to a low drug bioavailability in target tissues. The objective of this work is to develop an intraocular lens (IOL) material to deliver simultaneously one antibiotic, moxifloxacin (MXF), and one anti-inflammatory, diclofenac (DFN), in therapeutic concentrations to prevent both complications. The IOL material was modified through the incorporation of functional monomers, as well as molecular imprinting with both drugs using the same functional monomers, namely acrylic acid (AA), methacrylic acid (MAA), 4-vinylpiridine (4-VP) and a combination of MAA + 4-VP. The best results were obtained with MAA. Molecular imprinting did not influence the drug release, except with AA. Application of a mathematical model predicted that the released MXF and DFN concentrations would stay above the pre-determined MIC of S. aureus and S. epidermidis and the minimum values of IC50 of COX-1 and COX-2, for 9 and 14 days, respectively. Antibacterial tests showed that the released antibiotic remained active. The physical properties of the drug-loaded MAA-hydrogel remained adequate. The developed system proved to be non-irritant and non-cytotoxic. -
7
Preparação e Caracterização de membranas para lentes de contacto pós-cirúrgicas
Publicationby Raínho, Vera Mónica Ramos da SilvaA eficiência da administração de fármacos na terapia ocular após intervenções cirúrgicas é um dos grandes fatores que condiciona a recuperação dos pacientes. Nos dias de hoje, a administração de fármacos nestes casos é realizada na forma de colírios. No entanto, este método mostra-se muito ineficiente, surgindo o uso de sistemas de libertação controlada de fármacos como uma possível alternativa bastante promissora. No decorrer deste trabalho foram desenvolvidas membranas à base de acrilatos para serem usadas como sistemas de libertação controlada de um fármaco (sob a forma de lentes de contacto), sendo o fármaco selecionada a moxifloxacina (MFX), um antibiótico muito utilizado no pós-operatório da terapia ocular. Estas membranas foram desenvolvidas através do método de polimerização na massa. Deste modo foram preparadas membranas com diferentes monómeros na sua constituição. Uma vez que o desconforto causado pela radiação solar é outro dos fatores que influencia a recuperação pós-operatória, com o intuito de minimizar este desconforto, também foram incorporados corantes fotocrómicos nas membranas desenvolvidas. A membrana com melhores propriedades, preparada a partir de acrilato 2-etil-hexilo (EHA), metacrilato de metilo (MMA), peróxido de benzoílo (BPO) e dimetacrilato de etilenoglicol (EGDMA), designada AMB 7, foi caracterizada e nela foi incorporada MFX e corantes fotocrómicos, por oclusão. Com base nesta formulação, foram desenvolvidas mais duas formulações, a ABM 7.1 e ABM 7.2, com o intuito de avaliar a influência do aumento do agente de reticulação EGDMA nas propriedades finais das membranas. Foi ainda preparada uma membrana incluindo na formulação o monómero metacrilato de 2-hidroxietilo (HEMA), designada ABM 10, com a finalidade de aumentar a hidrofilicidade da membrana. Nestas membranas, somente se incluiu MFX por oclusão.As membranas preparadas foram caracterizadas quimicamente por espectroscopia de infravermelho com transformada de Fourier (FTIR), confirmando o sucesso da polimerização. Através da análise termogravimétrica (TGA) constatou-se a elevada estabilidade térmica dos materiais, sendo superiores a 350ºC.Os ângulos de contato, a transmitância e o teor de água das quatro membranas selecionadas foram determinados. No que diz respeito a molhabilidade das membranas determinado pela medição do ângulo de contacto, a ABM 7 foi a que apresentou melhores resultados (45º), dentro do intervalo de valores de lentes de contacto comerciais. Quanto à transmitância, a ABM 7 confere um maior grau de proteção relativamente a radiação UV ao passo que a ABM 7.1, apresenta melhores resultados relativamente à sua transparência. As membranas que contem corantes fotocrómicos incorporados, foram as que apresentaram maior proteção a radiação UV, no entanto, a sua coloração resulta numa diminuição da transparência das membranas. Analisando ainda o teor de água, os valores obtidos foram inferiores a 2%, sendo a ABM 10 a membrana que apresentou a maior capacidade de absorção de água, um valor muito baixo para uma aplicação como lente de contacto. Os resultados da libertação da MFX nos três sistemas de libertação que foram estudados (ABM 7, ABM 7.2 e ABM 10), permitiram concluir que a membrana ABM 7.2 é a que apresenta melhores resultados, uma vez que apresenta um máximo de libertação ao final de quatro dias e apresenta o maior valor de massa libertada de moxifloxacina. -
8
Biodegradation of the fluorinated antibiotic moxifloxacin
Publicationby Carvalho, Maria F.Other Authors: Maia, Alexandra; Tiritan, Maria E.; Castro, Paula M. L. -
9
Bacterial degradation of moxifloxacin in the presence of acetate as a bulk substrate
Publicationby Carvalho, M. F.Other Authors: Maia, A. S.; Tiritan, M. E.; Castro, P. M. L.Fluoroquinolones constitute a group of emerging pollutants and their occurrence in different environmental compartments is becoming object of increasing public concern due to their ecotoxicological effects and the potential to develop resistant bacteria. This study aimed to investigate the biodegradation of moxifloxacin (MOX), for which studies in the literature are very scarce. An activated sludge (AS) consortium and three bacterial strains able to degrade fluoroaromatic compounds e strains F11, FP1 and S2 e were tested. Biodegradation studies were conducted using acetate as a bulk carbon source. Strain F11 showed the highest biodegradation capacity, being able to completely consume and dehalogenate 7.5 mM of the target antibiotic when daily co-supplemented with acetate present as a readily degradable organic substrate in wastewaters. MOX could be used by strain F11 as a sole nitrogen source but the presence of an external nitrogen source in the culture medium was essential for complete biodegradation. Strain F11 was capable of completely consuming MOX in a range between 2 and 11 mM, although stoichiometric fluoride release was not obtained for the highest tested concentration. The antibacterial activity of residual MOX and of the metabolic products potentially resultant from the biodegradation process was investigated by agar diffusion tests, demonstrating that MOX biodegradation is associated with the elimination of the antibacterial properties of the target antibiotic and of the produced metabolites, which is an important result, as the activity of antibiotics and/or their metabolites in the environment, even at low levels, may lead to the development of resistant bacterial strains. Overall, the results obtained in this study suggest that strain F11 is a promising microorganism for the treatment of waters contaminated with MOX, where it could be used for bioaugmentation/bioremediation purposes. To the best of our knowledge, this is the first study reporting complete removal and dehalogenation of MOX by a single microorganism. -
10
Effect of moxifloxacin administration on pharmacokinetics of tolfenamic acid in rats
Publicationby Patel,Satish D.Other Authors: Sadariya,Kamlesh A.; Gothi,Anil K.; Patel,Urvesh D.; Gohil,Pradhuman A.; Jain,Mukul R. et al.Origin: OasisbrPharmacokinetics of tolfenamic acid as a single drug (4 mg/kg, intramuscularly) and its co-administration with moxifloxacin (5 mg/kg, intramuscularly) in wistar rats were studied. The plasma drug concentration of tolfenamic acid was assayed by LC-MS/MS. Following intramuscular administration of tolfenamic acid as single drug and in combination with moxifloxacin in male rats, the mean values of observed peak plasma drug concentration (Cmax), area under plasma drug concentration-time curve (AUC(0-¥) ), volume of distribution (Vz), half-life (t½) and clearance (Cl) were 4111.44 ± 493.15 and 3837.69 ± 351.83 ng/ml, 20280.77 ± 3501.67 and 15229.18 ± 678.80 ng.h/ml, 822.17 ± 115.38 and 1249.64 ± 139.52 ml, 2.59 ± 0.16 and 3.27 ± 0.32 hr, and 218.39 ± 25.47 and 265.18 ± 11.36 ml/hr, respectively. The peak plasma drug concentration (Cmax) was significantly higher in female rats compared to male rats. The volume of distribution (Vz) of the drug was significantly higher (P < 0.05) in moxifloxacin-treated male rats compared to female rats. Concomitant administration of moxifloxacin may alter the disposition of tolfenamic acid in male rats.
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