Anticandidal activity of synthetic peptides: Mechanism of action revealed by scanning electron and fluorescence microscopies and synergism effect with nystatin.

Candida albicans has emerged as a major public health problem in recent decades. The most important contributing factor is the rapid increase in resistance to conventional drugs worldwide. Synthetic antimicrobial peptides (SAMPs) have attracted substantial attention as alternatives and/or adjuvants in therapeutic treatments due to their strong activity at low concentrations without apparent toxicity. Here, two SAMPs, named Mo-CBP3 -PepI (CPAIQRCC) and Mo-CBP3 -PepII (NIQPPCRCC), are described, bioinspired by Mo-CBP3 , which is an antifungal chitin-binding protein from Moringa oleifera seeds. Furthermore, the mechanism of anticandidal activity was evaluated as well as their synergistic effects with nystatin. Both peptides induced the production of reactive oxygen species (ROS), cell wall degradation, and large pores in the C. albicans cell membrane. In addition, the peptides exhibited high potential as adjuvants because of their synergistic effects, by increasing almost 50-fold the anticandidal activity of the conventional antifungal drug nystatin. These peptides have excellent potential as new drugs and/or adjuvants to conventional drugs for treatment of clinical infections caused by C. albicans.

Activity of Fenticonazole, Tioconazole and Nystatin on New World Leishmania Species.

Leishmaniasis is an infectious disease caused by protozoal parasites belonging to Leishmania genus. Different clinical outcomes can be observed depending on the parasite species and health condition of patients. It can range from single cutaneous lesion until deadly visceral form. The treatment of all forms of leishmaniasis is based on pentavalent antimonials, and in some cases, the second-line drug, amphotericin B is used. Beside the toxicity of both drugs, parasites can be resistant to antimonial in some areas of the world. This makes fundamental the characterization of new drugs with leishmanicidal effect. Thus, the aim of the present work was to study the leishmanicidal activity of drugs able to interfere with ergosterol pathway (fenticonazole, tioconazole, nystatin, rosuvastatin and voriconazole) against promastigote and amastigote forms of L.(L.) amazonensis, L.(V.) braziliensis and L.(L.) infantum, and its impact on morphological and physiological changes in L.(L.) amazonensis or in host macrophages. We observed that fenticonazole, tioconazole and nystatin drugs eliminated promastigote and intracellular amastigotes, being fenticonazole and nystatin the most selective towards amastigote forms. Rosuvastatin and voriconazole did not present activity against amastigote forms of Leishmania sp. In addition, the drugs with leishmanicidal activity interfered with parasite mitochondrion. Although drugs did not stimulate NO and H2O2, specially fenticonazole was able to alkalize infected host macrophages. These results suggest well established and non-toxic antifungal drugs can be repurposed and used in leishmaniasis.

Stability and efficacy of combined nystatin and chlorhexidine against suspensions and biofilms of Candida albicans.

OBJECTIVE: Nystatin and chlorhexidine are extensively used in oral medicine; however, there is some controversy about the possibility of these drugs showing antagonism. To clarify this issue, this study investigated the efficacy and stability of nystatin and chlorhexidine in combination. DESIGN: An in vitro study was conducted to analyze the effect of nystatin and chlorhexidine combined on Candida albicans ATCC 18804, using the drugs mixed as a single formulation and as independent formulations used sequentially with different time intervals between them. The minimum inhibitory concentration (MIC) and effects on C. albicans suspensions and biofilms were evaluated. Also, the stability of nystatin and chlorhexidine in a mixture was tested by high performance liquid chromatography (HPLC). RESULTS: When nystatin and chlorhexidine were mixed in a single formulation, there was no significant difference in MIC compared to that of the drugs used alone (as the only treatment). However, when these drugs were used as independent formulations, sequentially with time intervals in between, their MICs were higher than the respective MIC of the drug used alone, except for the MIC of chlorhexidine with a 10-min interval. Nystatin/chlorhexidine combinations showed lower activity against C. albicans biofilms, except for that with a 30-min interval. The drugs when combined showed high percentages of degradation at all the times evaluated. CONCLUSIONS: The combination of nystatin and chlorhexidine seems to interfere with the efficacy of the drugs and to increase their rate of degradation.

Porosity of temporary denture soft liners containing antifungal agents.

OBJECTIVE:: To evaluate the porosity of a tissue conditioner (Softone) and a temporary resilient liner (Trusoft) modified by minimum inhibitory concentrations (MICs) of antifungal agents for Candida albicans biofilm. MATERIAL AND METHODS:: The porosity was measured by water absorption, based on exclusion of the plasticizer effect. Initially, it was determined by sorption isotherms that the adequate storage solution for specimens (65×10×3.3 mm) of both materials was 50% anhydrous calcium chloride (S50). Then, the porosity factor (PF) was calculated for the study groups (n=10) formed by specimens without (control) or with drug incorporation at MICs (nystatin: Ny-0.032 g, chlorhexidine diacetate: Chx-0.064 g, or ketoconazole: Ke-0.128 g each per gram of soft liner powder) after storage in distilled water or S50 for 24 h, seven and 14 d. Data were statistically analyzed by 4-way repeated measures ANOVA and Tukey's test (α=.05). RESULTS:: Ke resulted in no significant changes in PF for both liners in water over 14 days (p>0.05). Compared with the controls, Softone and Trusoft PFs were increased at 14-day water immersion only after addition of Ny and Chx, and Chx, respectively (p<0.05). Both materials showed no significant changes in PF in up to 14 days of S50 immersion, compared with the controls (p>0.05). In all experimental conditions, Softone and Trusoft PFs were significantly lower when immersed in S50 compared with distilled water (p<0.05). CONCLUSIONS:: The addition of antifungals at MICs resulted in no harmful effects for the porosity of both temporary soft liners in different periods of water immersion, except for Chx and Ny in Softone and Chx in Trusoft at 14 days. No deleterious effect was observed for the porosity of both soft liners modified by the drugs at MICs over 14 days of S50 immersion.

Porosity of temporary denture soft liners containing antifungal agents

ABSTRACT Incorporation of antifungals in temporary denture soft liners has been recommended for denture stomatitis treatment; however, it may affect their properties. Objective: To evaluate the porosity of a tissue conditioner (Softone) and a temporary resilient liner (Trusoft) modified by minimum inhibitory concentrations (MICs) of antifungal agents for Candida albicans biofilm. Material and Methods: The porosity was measured by water absorption, based on exclusion of the plasticizer effect. Initially, it was determined by sorption isotherms that the adequate storage solution for specimens (65×10×3.3 mm) of both materials was 50% anhydrous calcium chloride (S50). Then, the porosity factor (PF) was calculated for the study groups (n=10) formed by specimens without (control) or with drug incorporation at MICs (nystatin: Ny-0.032 g, chlorhexidine diacetate: Chx-0.064 g, or ketoconazole: Ke-0.128 g each per gram of soft liner powder) after storage in distilled water or S50 for 24 h, seven and 14 d. Data were statistically analyzed by 4-way repeated measures ANOVA and Tukey's test (α=.05). Results: Ke resulted in no significant changes in PF for both liners in water over 14 days (p>0.05). Compared with the controls, Softone and Trusoft PFs were increased at 14-day water immersion only after addition of Ny and Chx, and Chx, respectively (p<0.05). Both materials showed no significant changes in PF in up to 14 days of S50 immersion, compared with the controls (p>0.05). In all experimental conditions, Softone and Trusoft PFs were significantly lower when immersed in S50 compared with distilled water (p<0.05). Conclusions: The addition of antifungals at MICs resulted in no harmful effects for the porosity of both temporary soft liners in different periods of water immersion, except for Chx and Ny in Softone and Chx in Trusoft at 14 days. No deleterious effect was observed for the porosity of both soft liners modified by the drugs at MICs over 14 days of S50 immersion.

Efeito da incorporação de agentes antifúngicos na resistência à tração e porosidade de materiais resilientes temporários para base de próteses / Effect of incorporation of antifungal agents on the ultimate tensile strength and porosity of temporary soft denture liners

Este estudo investigou a resistência à tração (ou limite de resistência à tração- LRT) e a porosidade de reembasadores resilientes temporários modificados por concentrações inibitórias mínimas (CIMs) de agentes antifúngicos para o biofilme Candida albicans (SC5314). Para os testes de LRT, corpos de prova em forma de halteres (n=7) com uma área transversal de 33 mm x 6 mm x 3 mm foram produzidos para os materiais resilientes (Trusoft e Softone) sem (controle) ou com incorporação de cinco fármacos em suas CIMs: nistatina- 0,032 g; diacetato de clorexidina- 0,064; cetoconazol- 0,128 g; miconazol- 0,256 g; itraconazol-0,256 g (grama de fármaco por grama de pó de material resiliente). Após a plastificação, as amostras foram imersas em água destilada a 37°C durante 24 h, 7 e 14 dias e, então, testadas em tensão em uma máquina universal de ensaios (EMIC DL-500 MF) a 40 mm/min. A porosidade foi mensurada por absorção de água, com base na exclusão do efeito plastificante. Inicialmente, determinou-se por isotermas de sorção, que a solução de armazenagem adequada para os corpos de prova (65 mm x 10 mm x 3,3 mm) de ambos os materiais foi o cloreto de cálcio anidro a 50% (S50). Assim, o fator de porosidade (FP) foi calculado para os grupos de estudo (n=10) formados por espécimes sem (controle) ou com incorporação de fármaco em suas CIMs (nistatina, clorexidina ou cetoconazol) após a armazenagem em água destilada ou S50 por 24 h, 7 e 14 dias. Os dados de resistência à tração (MPa) e percentagem de alongamento (%) foram submetidos à ANOVA de 3 fatores seguida pelo teste de Tukey (=0,05). Os dados de porosidade foram analisados estatisticamente por ANOVA de medidas repetidas para 4 fatores e teste de Tukey (=0,05). Ao final de 14 dias, a resistência à tração para ambos os materiais foi significativamente menor nos grupos modificados pelo miconazol e itraconazol em relação aos outros grupos (P<0,0001), que não mostraram diferenças significativas entre si (P>0,05). Após 7 e 14 dias em água, o miconazol e itraconazol adicionados a ambos os materiais resultaram em percentagens significativamente menores de alongamento em comparação com os outros fármacos e ao controle (P<0,0001), que foram semelhantes entre si (P>0,05). O cetoconazol não resultou em alterações significativas no FP para ambos os materiais resilientes em água ao longo de 14 dias (P>0,05). Em comparação aos controles, houve aumento dos FPs do Softone e Trusoft aos 14 dias de imersão em água somente após a adição de nistatina e clorexidina e de clorexidina, respectivamente (P<0,05). Ambos os materiais não apresentaram alterações significativas no FP em até 14 dias de imersão na S50, em comparação aos controles (P>0,05). Em todas as condições experimentais, os FPs do Softone e Trusoft foram significativamente menores quando imersos em S50 em comparação com a água destilada (P<0,05). Concluiu-se que a adição de nistatina, clorexidina e cetoconazol nas CIMs para o biofilme de C. albicans não resultou em efeitos deletérios na resistência à tração e na percentagem de alongamento dos materiais resilientes temporários para base de prótese até o período de 14 dias. A adição de antifúngicos nas CIMs não resultou em efeitos adversos à porosidade de ambos os materiais resilientes temporários em diferentes períodos de imersão em água, com exceção da clorexidina e nistatina no Softone e clorexidina no Trusoft aos 14 dias. Não foram observados efeitos deletérios para a porosidade de ambos os materiais resilientes modificados com as CIMs dos fármacos durante os 14 dias de imersão na S50.(AU)

This study investigated the tensile strength (ultimate tensile strength- UTS) and porosity of temporary soft denture liners modified by minimum inhibitory concentrations (MICs) of antifungal agents for Candida albicans biofilm (SC5314). For UTS tests, dumbbell-shaped specimens (n=7) with a central cross-sectional area of 33 mm x 6 mm x 3 mm were produced by resilient materials (Trusoft and Softone) without (control) or with incorporation of five drugs at MICs: nystatin- 0.032 g; chlorhexidine diacetate-0.064 g; ketoconazole- 0.128 g; miconazole- 0.256 g; itraconazole- 0.256 g (each per gram of soft liner powder). After plasticization, specimens were immersed in distilled water at 37°C for 24 h, 7 and 14 days, and then tested in tension in a universal testing machine (EMIC DL-500 MF) at 40 mm/min. The porosity was measured by water absorption, based on exclusion of the plasticizer effect. Initially, it was determined by sorption isotherms that the adequate storage solution for specimens (65 mm x 10 mm x 3.3 mm) of both materials was 50% anhydrous calcium chloride (S50). Then, the porosity factor (PF) was calculated for the study groups (n=10) formed by specimens without (control) or with drug incorporation at MICs (nystatin, chlorhexidine or ketoconazole) after storage in distilled water or S50 for 24 h, 7 and 14 days. Data of tensile strength (MPa) and elongation percentage (%) were submitted to 3-way ANOVA followed by Tukey's test (=0.05). Data of porosity were statistically analyzed by 4-way repeated measures ANOVA and Tukeys test (=0.05). At the end of 14 days, the tensile strength for both materials was significantly lower in the groups modified by miconazole and itraconazole compared to the other groups (P<0.0001), which showed no significant difference between them (P>0.05). After 7 and 14 days in water, miconazole and itraconazole added into both materials result in significant lower elongation percentages compared to the other drugs and control (P<.0001), which were similar to each other (P>0.05). Ketoconazole resulted in no significant changes in PF for both liners in water over 14 days (P>0.05). Compared to the controls, Softone and Trusoft PFs were increased at 14-day water immersion only after addition of nystatin and chlorhexidine, and chlorhexidine, respectively (P<0.05). Both materials showed no significant changes in PF in up to 14 days of S50 immersion, compared to the controls (P>0.05). In all experimental conditions, Softone and Trusoft PFs were significantly lower when immersed in S50 compared to distilled water (P<0.05). It was concluded that the addition of the nystatin, chlorhexidine and ketoconazole at MICs for C. albicans biofilm resulted in no harmful effects on the ultimate tensile strength and elongation percentage of the temporary soft denture liners up to 14-day period. The addition of antifungals at MICs resulted in no detrimental effects for the porosity of both temporary soft liners in different periods of water immersion, except for chlorhexidine and nystatin in Softone and chlorhexidine in Trusoft at 14 days. No deleterious effect was observed for the porosity of both soft liners modified by the drugs at MICs over 14 days of S50 immersion.(AU)

Effect of the addition of antimicrobial agents on Shore A hardness and roughness of soft lining materials.

PURPOSE: While the incorporation of antimicrobial agents into soft denture liners has been suggested as a reliable alternative treatment for denture stomatitis, it may affect the liner's properties. The effect of addition of antimicrobial agents for the treatment of denture stomatitis on the surface roughness and Shore A hardness of soft lining materials was evaluated. MATERIALS AND METHODS: The test groups comprised specimens (36 × 7 × 6 mm(3) ) of soft materials (Softone and Trusoft) without (control) or with incorporation of drugs (nystatin, miconazole, ketoconazole, chlorhexidine diacetate, and itraconazole). Hardness (Shore A) and roughness (Ra) were evaluated after immersion of specimens (n = 10) in distilled water at 37°C for 24 hours, 7 and 14 days. Data were analyzed by 3-way ANOVA/Tukey's test (α = 0.05). RESULTS: After 14 days, an increase (p < 0.05) was observed in the hardness of soft materials with time for the modified specimens, except for itraconazole. Addition of drugs increased the Softone roughness only for the addition of miconazole and chlorhexidine (p < 0.05), and did not increase the roughness of Trusoft with time. Only chlorhexidine and itraconazole altered the roughness compared to the control for each material (p < 0.05). CONCLUSIONS: The smallest changes of hardness and roughness with time in the modified groups compared to controls were observed for itraconazole groups for both materials.

Peel bond strength of resilient liner modified by the addition of antimicrobial agents to denture base acrylic resin

In order to prolong the clinical longevity of resilient denture relining materials and reduce plaque accumulation, incorporation of antimicrobial agents into these materials has been proposed. However, this addition may affect their properties. OBJECTIVE: This study evaluated the effect of the addition of antimicrobial agents into one soft liner (Soft Confort, Dencril) on its peel bond strength to one denture base (QC 20, Dentsply). MATERIAL AND METHODS: Acrylic specimens (n=9) were made (75x10x3 mm) and stored in distilled water at 37ºC for 48 h. The drug powder concentrations (nystatin 500,000U - G2; nystatin 1,000,000U - G3; miconazole 125 mg - G4; miconazole 250 mg - G5; ketoconazole 100 mg - G6; ketoconazole 200 mg - G7; chlorhexidine diacetate 5% - G8; and 10% chlorhexidine diacetate - G9) were blended with the soft liner powder before the addition of the soft liner liquid. A group (G1) without any drug incorporation was used as control. Specimens (n=9) (75x10x6 mm) were plasticized according to the manufacturers' instructions and stored in distilled water at 37ºC for 24 h. Relined specimens were then submitted to a 180-degree peel test at a crosshead speed of 10 mm/min. Data (MPa) were analyzed by analysis of variance (α=0.05) and the failure modes were visually classified. RESULTS: No significant difference was found among experimental groups (p=0.148). Cohesive failure located within the resilient material was predominantly observed in all tested groups. CONCLUSIONS: Peel bond strength between the denture base and the modified soft liner was not affected by the addition of antimicrobial agents.

Peel bond strength of resilient liner modified by the addition of antimicrobial agents to denture base acrylic resin.

UNLABELLED: In order to prolong the clinical longevity of resilient denture relining materials and reduce plaque accumulation, incorporation of antimicrobial agents into these materials has been proposed. However, this addition may affect their properties. OBJECTIVE: This study evaluated the effect of the addition of antimicrobial agents into one soft liner (Soft Confort, Dencril) on its peel bond strength to one denture base (QC 20, Dentsply). MATERIAL AND METHODS: Acrylic specimens (n=9) were made (75x10x3 mm) and stored in distilled water at 37 ºC for 48 h. The drug powder concentrations (nystatin 500,000 U--G2; nystatin 1,000,000 U--G3; miconazole 125 mg--G4; miconazole 250 mg--G5; ketoconazole 100 mg - G6; ketoconazole 200 mg--G7; chlorhexidine diacetate 5%--G8; and 10% chlorhexidine diacetate--G9) were blended with the soft liner powder before the addition of the soft liner liquid. A group (G1) without any drug incorporation was used as control. Specimens (n=9) (75x10x6 mm) were plasticized according to the manufacturers' instructions and stored in distilled water at 37 ºC for 24 h. Relined specimens were then submitted to a 180-degree peel test at a crosshead speed of 10 mm/min. Data (MPa) were analyzed by analysis of variance (α=0.05) and the failure modes were visually classified. RESULTS: No significant difference was found among experimental groups (p=0.148). Cohesive failure located within the resilient material was predominantly observed in all tested groups. CONCLUSIONS: Peel bond strength between the denture base and the modified soft liner was not affected by the addition of antimicrobial agents.

Poly (Methyl Methacrylate) absorption and releasing of nystatin and fluconazole / Absorção e liberação de nistatina e fluconazol por polimetilmetacrilato

Objectives: The aim of this study was to verify if there are poly (methyl methacrylate) (PMMA) absorptionand releasing of nystatin (NYS) and fluconazole (FLZ) after simulated treatment of oral candidosis. Materialsand methods: Specimens (30 × 25 × 5 mm) prepared with PMMA polymerized by hot water bath or microwaveenergy were immersed into NYS (3.12 μg/mL), FLZ (2.56 μg/mL) or deionized water (control) during14 days at 35 ± 2 °C. After treatment simulation, specimens were immersed into distilled water during 3, 7, 10and 14 days. The immersion liquid was changed after each analysis. Higher performance liquid chromatographywas used in order to detect antifungal compounds. In order to determine if there was surface depositionof drugs on PMMA resin, specimens were analyzed with electronic microscopy (SEM). Results: None of theantifungal agents was released from the PMMA resins. Conclusion: Within the limitations of this study, itcould be concluded that PMMA resins had no drug absorption with posterior release.

Objetivos: O objetivo deste estudo foi verificar se o poli (metil metacrilato) (PMMA) é capaz de absorver e liberar nistatina (NYS) e fluconazol (FLZ) após simular um tratamento para candidose oral. Materiais e métodos:Espécimes (30 × 25 × 5 mm) foram preparados em resina de PMMA por banho de água quente ou energia demicro-ondas e, em seguida, imersos em solução contendo NYS (3.12 μg/mL), FLZ (2.56 μg/mL) ou água deionizada(controle) durante 14 dias a 35 ± 2 °C. Após a simulação de tratamento, os espécimes foram imersos em água destilada durante 3, 7, 10 e 14 dias. O líquido de imersão foi trocado após cada análise. Cromatografia líquida de alta performance foi utilizada para detectar a presença dos agentes antifúngicos. Para determinar se houve deposição dos agentes antifúngicos na superfície de PMMA, os espécimes foram analisados por microscopia eletrônica de varredura(MEV). Resultados: Não houve liberação de agentes antifúngicos dos espécimes. Conclusão: Considerando as limitações deste estudo, pode-se concluir que a resina de PMMA não absorve ou libera agentes antifúngicos.

Preparation and evaluation of antimicrobial activity of nanosystems for the control of oral pathogens Streptococcus mutans and Candida albicans.

BACKGROUND: Diseases that affect the buccal cavity are a public health concern nowadays. Chlorhexidine and nystatin are the most commonly used drugs for the control of buccal affections. In the search for more effective antimicrobials, nanotechnology can be successfully used to improve the physical chemical properties of drugs whilst avoiding the undesirable side effects associated with its use. Herein described are studies using nystatin and chlorhexidine with sodium montmorillonite (MMTNa), and chlorhexidine with ß-cyclodextrin and two derivatives methyl-ß-cyclodextrin and hydroxypropyl-ß-cyclodextrin in the development of antimicrobial nanosystems. METHODS: The nanosystems were prepared by kneading and solubilization followed by freeze-drying technique. The nanosystems were characterized by X-ray powder diffraction (XRPD), differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR). Nanosystem antimicrobial activity against Streptococcus mutans and Candida albicans strains was evaluated with inhibition halo analysis. RESULTS: The nanocarriers MMTNa and cyclodextrins showed good yields. XRPD, FTIR, and DSC analysis confirmed the proposed nanosystems formation and the suitability of the production methods. The nanosystems that showed best antimicrobial effect were chlorhexidine gluconate (CHX) and cyclodextrin inclusion complexes and CHX:MMTNa 60% cation exchange capacity - 24 hours. CONCLUSION: The nanosystem formulations present higher stability for all chlorhexidine inclusion complexes compared with pure chlorhexidine. The nystatin nanosystems have the potential to mask the bitter taste, justifying subsequent in-vivo studies. For these reasons, further studies are being carried out to evaluate their application in professional formulations.

Effect of membrane structure on the action of polyenes II: nystatin activity along the phase diagram of ergosterol- and cholesterol-containing POPC membranes.

Pores formed by the polyene antibiotic nystatin were studied in solvent-free lipid membranes. The membranes were formed by the tip-dip technique using 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) with different mol fractions (0-50%) of cholesterol or ergosterol. The effects of the mol fraction of sterol and of temperature variation (15-35°C) on the activity of the pores, their unitary conductances, lifetimes and time average conductances were studied. The results were used to analyze the behavior of nystatin channels along the phase diagrams previously reported for these lipid mixtures and to propose that membrane structure is the determinant factor for the known ergosterol/cholesterol selectivity.

Effect of membrane structure on the action of polyenes: I. Nystatin action in cholesterol- and ergosterol-containing membranes.

A detailed and thorough characterization of nystatin-induced permeability on lipid bilayers of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)-containing ergosterol or cholesterol is presented. The results show that the same collection of transmembrane pores appears in membranes containing either sterol. The concentration range for the appearance of these pores is sterol-dependent. Another mechanism of action, membrane disruption, is also observed in ergosterol-POPC membranes. The greater potency of nystatin present in ergosterol-containing membranes cannot be explained simply by the longer opening times of its pores, as has been suggested; it is also due to an increased number of events in these membranes. The present results and those of a companion paper lead us to propose that membrane structure is the determining factor for drug selectivity in membranes with different sterols.

Superficial distribution and identification of antifungal/antimicrobial agents on a modified tissue conditioner by SEM-EDS microanalysis: a preliminary study.

PURPOSE: This study evaluated the incorporation pattern of antifungal/antimicrobial agents added to a tissue conditioner by scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) analysis. MATERIALS AND METHODS: The nystatin dosages incorporated into the tissue conditioner (Softone, Bosworth Co., Skokie, IL) powder were 500,000 U (G1) and 1,000,000 U (G2). The addition of miconazole was at 125 mg (G3) and 250 mg (G4), and ketoconazole was at 100 mg (G5) and 200 mg (G6). Chlorhexidine diacetate was blended at levels of 5% (G7) and 10% (G8) w/w of the total amount (6.35 g) of the tissue conditioner. The drug powder concentrations were blended with the tissue conditioner powder at different concentrations before the addition of the tissue conditioner liquid (5 mL) to the mixture. One group (G0) without any drug incorporation was used as control. Specimens (n = 5) (36 x 7 x 6 mm(3)) were plasticized at room temperature for 10 minutes and carbon sputter coated. All specimens were submitted to SEM-EDS analysis. RESULTS: Nystatin and miconazole specimens exhibited particles with irregular shapes and sizes uniformly distributed. Ketoconazole specimens showed small spherical particles with a slight distribution throughout the matrix. Chlorhexidine specimens exhibited irregular particles up to approximately 50 mum in size randomly dispersed within the matrix. CONCLUSIONS: Within the limitations of this in vitro study, the modified tissue conditioner showed differences in the particle distribution and size of the antifungal/antimicrobial agent added to the plasticized matrix. Further studies would discriminate the most important particle features that may influence the drug leaching from the plasticized matrix.

Effects of nystatin, fluconazole and propolis on poly(methyl methacrylate) resin surface.

The prevalence of candidosis in denture wearers is as well established as its treatment with antifungal agents (AAs). However, little research has been done regarding the effects of AAs on denture base surfaces. Therefore, the aim of this study was to evaluate the effects of fluconazole (FLU), nystatin (NYS) and propolis orabase gel (PRO) on poly (methyl-methacrylate) (PMMA) surfaces. Deionized water and orabase gel without any active component were used as control groups. Conventional heat-polymerized (Clássico) and microwave-polymerized (Onda Cryl) acrylic resins were used. After polymerization, the specimens were polished and had their surfaces evaluated for roughness, free energy and Knoop hardness. Subsequently, specimens were immersed in AAs and controls for 14 days at 35+/-2 degrees C and all variables were measured again. Data were analyzed statistically by 2-way ANOVA followed by Tukey's test (alpha=0.05). Roughness results showed similar behavior for both PMMA resins, with PRO reaching the highest values and differing significantly from the other AAs (p<0.05). No statistically significant differences (p>0.05) were found between the two PMMA resins or between NYS and FLU as regards surface free energy. In conclusion, PRO was able to induce changes in PMMA surface properties, such as roughness, which could be related to microbial adhesion.

Formulation and characterization of nystatin gel.

The main objective of this research is to develop and characterize a series of carbopol 934 (CP) hydroxypropyl methylcellulose (HPMC) and a combination of carbopol-HPMC as a gel base for topical delivery of nystatin. The drug level was held constant at 1.72% w/w and the level of propylene glycol which is used as a co-solvent and penetration enhancer was also kept constant at 2% w/w. The total level of the polymer was held constant at 1.5% w/w as a single polymer or combination of two polymers. The polymers combination selected were: carbopol 934 to HPMC at a ratio of 0:1, 1:0, 1:2, 2:1 and 1:1. The batch size was 500 g and triethanolamine was used to adjust the pH of the gel. The rheological study showed that formulation containing combination of 2 carbopol and 1 HPMC ratio gave the highest viscosity, and exhibited an apparent pseudoplastic thixotropic behavior. The diffusion study indicated that gel formulation containing carbopol-HPMC at a ratio of 2:1 gave the highest percent drug diffusion compared to formulation containing low carbopol to HPMC ratio, carbopol alone or HPMC alone. Both in-vitro release and rheological study indicated that carbopol-HPMC had the best gel strength, physical properties and ability to diffuse the drug than carbopol or HPMC alone. The results obtained in this study demonstrated that the combination of carbopol and hydroxypropyl methylcellulose can be used as a gel vehicle for nystatin topical application.

Formulation and characterization of nystatin gel

The main objective of this research is to develop and characterize a series of carbopol 934 (CP) hydroxypropyl methylcellulose (HPMC) and a combination of carbopol-HPMC as a gel base for topical delivery of nystatin. The drug level was held constant at 1.72% w/w and the level of propylene glycol which is used as a co-solvent and penetration enhancer was also kept constant at 2% w/w. The total level of the polymer was held constant at 1.5% w/w as a single polymer or combination of two polymers. The polymers combination selected were: carbopol 934 to HPMC at a ratio of 0:1, 1:0, 1:2, 2:1 and 1:1. The batch size was 500 g and triethanolamine was used to adjust the pH of the gel. The rheological study showed that formulation containing combination of 2 carbopol and 1 HPMC ratio gave the highest viscosity, and exhibited an apparent pseudoplastic thixotropic behavior. The diffusion study indicated that gel formulation containing carbopol-HPMC at a ratio of 2:1 gave the highest percent drug diffusion compared to formulation containing low carbopol to HPMC ratio, carbopol alone or HPMC alone. Both in-vitro release and rheological study indicated that carbopol-HPMC had the best gel strength, physical properties and ability to diffuse the drug than carbopol or HPMC alone. The results obtained in this study demonstrated that the combination of carbopol and hydroxypropyl methylcellulose can be used as a gel vehicle for nystatin topical application.

Effects of nystatin, fluconazole and propolis on poly (methyl methacrylate) resin surface

The prevalence of candidosis in denture wearers is as well established as its treatment with antifungal agents (AAs). However, little research has been done regarding the effects of AAs on denture base surfaces. Therefore, the aim of this study was to evaluate the effects of fluconazole (FLU), nystatin (NYS) and propolis orabase gel (PRO) on poly (methyl-methacrylate) (PMMA) surfaces. Deionized water and orabase gel without any active component were used as control groups. Conventional heat-polymerized (Clássico) and microwave-polymerized (Onda Cryl) acrylic resins were used. After polymerization, the specimens were polished and had their surfaces evaluated for roughness, free energy and Knoop hardness. Subsequently, specimens were immersed in AAs and controls for 14 days at 35±2 °C and all variables were measured again. Data were analyzed statistically by 2-way ANOVA followed by Tukey's test ( α=0.05). Roughness results showed similar behavior for both PMMA resins, with PRO reaching the highest values and differing significantly from the other AAs (p<0.05). No statistically significant differences (p>0.05) were found between the two PMMA resins or between NYS and FLU as regards surface free energy. In conclusion, PRO was able to induce changes in PMMA surface properties, such as roughness, which could be related to microbial adhesion.

A alta prevalência da candidose em usuários de prótese dental removível e a sua terapêutica com agentes antifúngicos (AA) está estabelecida. Contudo, o efeito dos AA sobre a superfície da resina de poli(metil-metacrilato) (PMMA) ainda não foi estudada. Assim, objetivou-se avaliar o efeito do fluconazol (FLU), nistatina (NYS) e gel orabase de própolis (GO) sobre a superfície de PMMA. Água deionizada e GO sem princípio ativo foram utilizadas como controles. Espécimes fabricados com PMMA polimerizada em banho de água ou com energia de microondas receberam acabamento e polimento e tiveram a rugosidade de superfície (RS), energia livre de superfície (ELS) e dureza Knoop (DK) mensuradas. Os tratamentos de superfície foram obtidos pela imersão dos espécimes nos AA durante 14 dias. Os resultados obtidos foram analisados por ANOVA para dois fatores e para a comparação, entre tratamentos e resinas, o teste de Tukey (α=0,05) foi utilizado. Os resultados mostraram que ambas as resinas aumentaram RS e ELS, mas não diferiram entre si (p>0,05). Os grupos tratados com própolis mostraram valores maiores de RS e diferente dos demais AAs (p<0,05). Com relação a rugosidade e energia livre de superfície não foram encontradas diferenças entre as PMMAs e entre FLU e NYS. Concluiu-se que a própolis induziu modificações na superfície de PMMA aumentando a rugosidade, fator que poderá facilitar a adesão de microrganismos.

Design of novel antifungal mucoadhesive films. Part II. Formulation and in vitro biopharmaceutical evaluation.

This paper deals with the formulation of the mucoadhesive films containing nystatin. The design and formulation of the films were based on the mucoadhesive properties of carbomer 934P (CB) and carboxymethycellulose (NaCMC), and also on the plasticizer properties of polyethyleneglycol 400 (PEG400). A surfactant (ascorbyl palmitate, ASC16) was added to the system to aid in nystatin dispersion. Addition of these last two components produced a significant improvement in physical-mechanical properties (flexibility and strength) as well as an increase in the nystatin release rate. X-ray powder diffraction (XRPD) and scanning electronic microscopy (SEM) were used to evaluate the morphological changes in the films while PEG400 and ASC16 were added to the formulations. Furthermore, the in vitro nystatin profile release was determined.

Design of novel antifungal mucoadhesive films Part I. Pre-formulation studies.

In this work, pre-formulation studies concerning the design of novel mucoadhesive films have been carried out. The rationality of the design is based on the utilization of mucoadhesive polymers (carbomer and carboxymethylcellulose), a plasticizer (polyethyleneglycol 400, PEG400) and a surfactant (ascorbyl palmitate, ASC16). In the gel preparation, the casting method using water as a solvent was employed. To provide a better understanding of the structural arrangements produced during the casting process, the changes in morphology (Cryo-TEM) and rheology (viscosity) of the film forming gel were evaluated. When PEG400 was included as a plasticizer, a disorder was produced in the network, reflected in the globular structure adopted by the gel and the consequent decrease in viscosity. The addition of ASC16 improved the solubilization of nystatin and provoked a decrease in gel viscosity. However, as water was removed during casting, ASC16 produced a significant increase in the viscosity at the point in which the polymer concentrations were sufficient to strengthen the inter-polymeric interactions, giving rise to a more rigid tri-dimensional network.