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1.
Pharm Dev Technol ; 25(4): 482-491, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31903830

RESUMO

Hypericin (Hyp), a natural hydrophobic and photoactive pigment, and methylene blue (MB), a hydrophilic cationic dye, are utilized as photosensitizer (PS) for photodynamic therapy of cancer. Bioadhesive and thermoresponsive polymeric systems can improve the drug availability by increasing the contact time between the system and the mucosa and also controlling the drug release. In this work, an accelerated physicochemical stability study of binary polymeric systems composed of poloxamer 407 (Polox) and Carbopol 934 P (Carb) for MB or Hyp release was performed. Formulations were prepared containing Polox (20%, w/w), Carb (0.15%, w/w) and MB (0.25%, w/w) or Hyp (0.01%, W/W) and submitted to different stress conditions (5 ± 3 °C, 25 ± 2 °C and 40 ± 2 °C with relative humidity of 75 ± 5%) during 180 days. The samples were analyzed as macroscopic characteristics, photosensitizer content and mechanical properties by texture profile analysis. Both systems displayed decrease of photosensitizer content less than 5% during 180 days. MB-system showed an undefined reaction model, while Hyp-system displayed PS decay following a pseudo first-order reaction. Systems also displayed stable mechanical characteristics. The pharmaceutical analyses showed the good physicochemical stability of the bioadhesive platform for delivery Hyp and MB in photodynamic therapy.


Assuntos
Preparações de Ação Retardada/química , Azul de Metileno/administração & dosagem , Perileno/análogos & derivados , Fármacos Fotossensibilizantes/administração & dosagem , Acrilatos/química , Adesivos/química , Antracenos , Sistemas de Liberação de Medicamentos , Liberação Controlada de Fármacos , Estabilidade de Medicamentos , Humanos , Azul de Metileno/química , Neoplasias/tratamento farmacológico , Perileno/administração & dosagem , Perileno/química , Fotoquimioterapia , Fármacos Fotossensibilizantes/química , Poloxâmero/química , Temperatura
2.
Pharm Res ; 33(3): 776-91, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26553353

RESUMO

PURPOSE: Photodynamic therapy (PDT) with methylene blue (MB) constitutes a potentially useful modality for colorectal cancer treatment. The limitations of the formulations containing MB are problems of administration and the inability to get the closeness contact at the site during the appropriate residence time. Present study aimed to develop and characterize mucoadhesive thermoresponsive system containing MB designed as platform for colorectal cancer therapy. METHODS: Formulations composed of different amounts of poloxamer 407 (Polox), Carbopol 934P (Carb), and MB were developed and characterized as rheological, compressional, mucoadhesive and syringeability properties, toxicity, photodynamic action, in vitro MB release profile, and ex vivo MB intestinal permeation. RESULTS: The different compositions resulted in formulations with distinctive macroscopic characteristics and wide range of gelation temperatures. The compressional flow, mucoadhesive, syringeability, and rheological properties were significantly influenced by temperature and/or composition. The MB release from formulation was governed by anomalous transport. In addition, it was observed that MB permeated the intestinal membrane; the formulation possesses photodynamic activity and low toxicity. CONCLUSIONS: The data obtained from the system composed of 20% Polox, 0.15% Carb, and 0.25% MB indicated a potentially functional role in PDT of the colorectal cancer and suggest it is worthy of clinical evaluation.


Assuntos
Adesividade/efeitos dos fármacos , Neoplasias Colorretais/tratamento farmacológico , Azul de Metileno/administração & dosagem , Azul de Metileno/química , Acrilatos/química , Animais , Células CACO-2 , Linhagem Celular Tumoral , Química Farmacêutica/métodos , Géis/administração & dosagem , Géis/química , Humanos , Masculino , Permeabilidade , Fotoquimioterapia/métodos , Poloxâmero/química , Ratos , Ratos Wistar
3.
Curr Drug Deliv ; 15(1): 64-76, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-28571541

RESUMO

BACKGROUND: Methylene blue (MB) is a photosensitizer used in photodynamic therapy (PDT) to treat colorectal cancer tumors and leishmaniasis infection. The clinical efficacy of PDT using MB is dependent on the physicochemical characteristics of the formulation. Bioadhesive thermoresponsive systems containing poloxamer 407 and Carbopol 934P have been proposed as platforms for PDT. However, the effect of MB on the physicochemical properties of these platforms is not fully understood, particularly in light of the MB availability. OBJECTIVE: The aim of this study was to investigate the dielectric characteristics of functional polymeric systems containing MB and their influence on mucoadhesion and drug release. METHODS: Binary polymeric systems containing different concentrations of poloxamer 407, Carbopol 934P and MB were evaluated as dielectric and mucoadhesive properties, as well as in vitro drug release profile. RESULTS: MB, temperature and polymeric composition influenced the physicochemical properties of the systems. The presence of MB altered the supramolecular structure of the preparations. The mucoadhesive properties of systems were influenced by MB presence and the formulation with the lowest amount of MB displayed faster release. CONCLUSION: The lower MB concentration in the systems displayed better results in terms of ionic mobility and drug release, and is indicative of a suitable clinical performance.


Assuntos
Acrilatos/química , Azul de Metileno/química , Poloxâmero/química , Polímeros/química , Adesividade , Espectroscopia Dielétrica , Sistemas de Liberação de Medicamentos
4.
J Mech Behav Biomed Mater ; 68: 265-275, 2017 04.
Artigo em Inglês | MEDLINE | ID: mdl-28219852

RESUMO

Polycarbophil is widely used in a variety of pharmaceutical formulations, mainly for their strong ability to adhere to the epithelial and mucous barriers (bio/mucoadhesion). On the other hand, its association with the thermoresponsive polymer (poloxamer 407) has been poorly explored. This work investigates the rheological, mechanical and mucoadhesive properties of polymer blends containing polycarbophil and poloxamer 407, in order to select the best formulations for biomedical and pharmaceutical applications. Mechanical (hardness, compressibility, adhesiveness, softness, and mucoadhesion) and rheological characteristics (consistency index, yield value and hysteresis area) showed that 20% (w/w) poloxamer 407- polymer blends exhibited higher values parameters. However, the rheological interaction parameter, which was more sensible than the mechanical interaction parameter, revealed higher synergism for systems comprising 15% (w/w) poloxamer 407, due to the system organization and polymers' properties. Furthermore, gelation temperatures were appropriated, suggesting that polymer blends can be used as biomedical materials, and displaying easy administration, enhanced retention and prolonged residence time at the site of application. Therefore, rheological, mechanical and mucoadhesive characterization provided a rational basis for selecting appropriated systems, useful for mucoadhesive drug delivery systems and biomedical applications.


Assuntos
Resinas Acrílicas/química , Poloxâmero/química , Adesividade , Teste de Materiais , Reologia
5.
Photodiagnosis Photodyn Ther ; 19: 284-297, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28669792

RESUMO

Hypericin (Hyp) is a natural photoactive pigment utilized in the treatment of different types of cancer and antimicrobial inactivation using photodynamic therapy (PDT). Hyp is poorly soluble in water leading to problems of administration, getting close contact with the site, and bio-availability. Therefore, this study aimed to develop bioadhesive thermoresponsive system containing Hyp for local PDT. Carbomer 934P, poloxamer 407, and Hyp were used to prepare the thermoresponsive bioadhesive formulations. They were characterized for sol-gel transition temperature, mechanical, mucoadhesive, rheological (continuous flow and oscillatory) and dielectric properties, syringeability, in vitro Hyp release kinetics, ex vivo permeability, and photodynamic activity. The formulations displayed suitable gelation temperature and rheological characteristics. The compressional, mechanical and mucoadhesive properties, as well the syringeability showed the easiness of administration and the permanence of the system adhered to the mucosa or skin. The dielectric analysis helped to understand the Hyp availability, and its release presented an anomalous behavior. The system did not permeate the pig skin nor rat intestine and showed good biological photodynamic activity. Therefore, data obtained from the bioadhesive system indicate a potentially useful role as a platform for local hypericin delivery in PDT, suggesting it is worthy of in vivo evaluation.


Assuntos
Sistemas de Liberação de Medicamentos/métodos , Perileno/análogos & derivados , Fotoquimioterapia/métodos , Fármacos Fotossensibilizantes/administração & dosagem , Resinas Acrílicas/química , Animais , Antracenos , Liberação Controlada de Fármacos , Géis/química , Absorção Intestinal/fisiologia , Fenômenos Mecânicos , Perileno/administração & dosagem , Perileno/farmacocinética , Fármacos Fotossensibilizantes/farmacocinética , Poloxâmero/química , Ratos , Reologia , Absorção Cutânea/fisiologia , Suínos , Aderências Teciduais
6.
J Mech Behav Biomed Mater ; 55: 164-178, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26590909

RESUMO

The development of binary polymeric mixtures (polymer blends) containing bioadhesive and thermoresponsive polymers can provide new materials for biomedical applications, with higher contact, increased adhesion, prolonged residence time, protection, and in determined cases, secured absorption of an active agent from the site of application. Mixtures were prepared using a wide range of poloxamer 407 and Carbopol 971P(®) amounts. The rheological (flow and oscillatory), sol-gel transition temperature, mechanical (hardness, compressibility, adhesiveness, cohesiveness and elasticity), softness, and mucoadhesive properties of formulations were investigated. Moreover, the interaction between the different proportions of polymers was also analyzed. Continuous shear and oscillatory rheometry identified the plastic flow with various degrees of thixotropy, besides the viscoelastic behavior of formulations. The determination of gelation temperature displayed values ranged from 27.17 to 41.09°C. It was also found that low carbomer concentrations were enough to provide positive interaction parameter. However, the highest values were obtained for the polymeric blends with higher concentration of poloxamer 407. The mucoadhesion and softness index were greater in preparations containing 20% (w/w) poloxamer 407. The rheological, mechanical and mucoadhesive properties of the polymeric blends can be manipulated by changing the concentrations of the polymers and they suggest the blends are worthy of biomedical applications.


Assuntos
Materiais Biocompatíveis/química , Fenômenos Mecânicos , Poloxâmero/química , Reologia , Temperatura , Adesividade , Animais , Força Compressiva , Mucinas/química , Mucosa/química , Resistência ao Cisalhamento , Suínos , Temperatura de Transição
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