Detrimental Effects of Chlorhexidine on Articular Cartilage Viability, Matrix, and Mechanics.

BACKGROUND: Chlorhexidine gluconate (CHG) solution is commonly used as an antiseptic irrigation for bacterial decontamination during orthopaedic surgery. Although the chondrotoxicity of CHG on articular cartilage has been reported, the full extent of CHG-related chondrotoxicity and its effects on the extracellular matrix and mechanical properties are unknown. PURPOSE: To investigate the in vitro effects of a single 1-minute CHG exposure on the viability, biochemical content, and mechanics of native articular cartilage explants. STUDY DESIGN: Controlled laboratory study. METHODS: Articular cartilage explants (6 per group) were harvested from femoral condyles of the porcine stifle and sectioned at tidemark. Explants were bathed in CHG solution (0.05% CHG in sterile water) at varying concentrations (0% control, 0.01% CHG, and 0.05% CHG) for 1 minute, followed by complete phosphate-buffered saline wash and culture in chondrogenic medium. At 7 days after CHG exposure, cell viability, matrix content (collagen and glycosaminoglycan [GAG]), and compressive mechanical properties (creep indentation testing) were assessed. RESULTS: One-minute CHG exposure was chondrotoxic to explants, with both 0.05% CHG (2.6% ± 4.1%) and 0.01% CHG (76.3% ± 8.6%) causing a decrease in chondrocyte viability compared with controls (97.5% ± 0.6%; P < .001 for both). CHG exposure at either concentration had no significant effect on collagen content, while 0.05% CHG exposure led to a significant decrease in mean GAG per wet weight compared with the control group (2.6% ± 1.7% vs 5.2% ± 1.9%; P = .029). There was a corresponding weakening of mechanical properties in explants treated with 0.05% CHG compared with controls, with decreases in mean aggregate modulus (177.8 ± 90.1 kPa vs 280.8 ± 19.8 kPa; P < .029) and shear modulus (102.6 ± 56.5 kPa vs 167.9 ± 16.2 kPa; P < .020). CONCLUSION: One-minute exposure to CHG for articular cartilage explants led to dose-dependent decreases in chondrocyte viability, GAG content, and compressive mechanical properties. This raises concern for the risk of mechanical failure of the cartilage tissue after CHG exposure. CLINICAL RELEVANCE: Clinicians should be judicious regarding the use of CHG irrigation at these concentrations in the presence of native articular cartilage.

Antibacterial and antifungal capacity of three commercially available mouthwashes with different concentrations of chlorhexidine / Efecto antibacteriano y antifúngico de tres enjuagues bucales comerciales con diferentes concentraciones de clorhexidina

Abstract Chlorhexidine was introduced almost seven decades ago and has a myriad of applications in dentistry. Few studies have evaluated the antimicrobial and antifungal capacity of different concentrations of chlorhexidine mouthwashes. Therefore, the aim of this study, was to evaluate in vitro, the antibacterial and antifungal capacity of three commercially available mouthwashes in Costa Rica, with different concentrations of chlorhexidine, 0.12%, 0.06%, and 0.03%. The experimental method selected was the Kirby-Bauer method to evaluate the antibacterial and antifungal effect of each compound by measuring the inhibitory effect on Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Candida albicans strains, exposed to the antiseptic solutions. All samples showed some degree of antibacterial and antifungal effect. Even though we provide in vitro results, our findings are of relevance since all the species used in our experiment are microorganisms that may be present in dental plaque. Our results further support evidence that oral hygiene regimens may include mouthwashes with low doses of chlorhexidine and maintain reasonable antibacterial and antifungal efficacy.

Resumen La clorhexidina se introdujo hace casi siete décadas y tiene una gran variedad de aplicaciones en odontología. Pocos estudios han evaluado la capacidad antimicrobiana y antifúngica de diferentes concentraciones de enjuagues bucales con clorhexidina. Por lo tanto, el objetivo de este estudio fue evaluar in vitro, la capacidad antibacteriana y antifúngica de tres enjuagues bucales disponibles comercialmente en Costa Rica, con diferentes concentraciones de clorhexidina, 0.12%, 0.06% y 0.03%. El método experimental seleccionado fue el método Kirby-Bauer para evaluar el efecto antibacteriano y antifúngico de cada compuesto midiendo el efecto inhibidor sobre Staphylococcus aureus, Enterococcus faecalis, Escherichia coli y Candida albicans, expuestos a la solución antiséptica. Todas las muestras mostraron algún grado de efecto antibacteriano y antifúngico. Aunque proporcionamos resultados in vitro, nuestros hallazgos son de relevancia, ya que todas las especies utilizadas en nuestro experimento son microorganismos que pueden estar presentes en la placa dental. Nuestros resultados respaldan aún más la evidencia de que los regímenes de higiene bucal pueden incluir enjuagues bucales con dosis bajas de clorhexidina y mantener una eficacia antibacteriana y antifúngica razonable.

Ex vivo and in vivo evaluation of residual chlorhexidine gluconate on skin following repetitive exposure to saline and wiping with 2% chlorhexidine gluconate/70% isopropyl alcohol pre-operative skin preparations.

BACKGROUND: Skin antisepsis is performed before surgery to minimize the risk of surgical site infections. Chlorhexidine gluconate (CHG) is routinely used in this application, but it may be removed during surgery when prepped areas are exposed to fluid and repeated blotting. AIM: This work evaluated the effect of adding a film-forming acrylate copolymer to a CHG-containing skin preparation on minimizing CHG loss during a simulated surgical irrigation and wiping procedure. The results were compared with those obtained with a commercially available water-soluble CHG preparation. METHODS: Two studies using excised porcine skin and one study on human volunteers were performed. In each study, the CHG preparations were applied and the treated sites were challenged with repetitive saline soaks and gauze dabbing to simulate surgical conditions. Challenged and unchallenged sites were analysed either for CHG content by high-performance liquid chromatography, or for bacterial log recovery after seeding an indicator organism (reflecting remaining CHG activity). FINDINGS: After irrigation and wiping, skin treated with the film-forming CHG preparation had more CHG remaining both on excised pig skin and in the human model. In the pig model, there was a lower recovery of inoculated bacteria with the CHG preparation containing the film-forming copolymer. No skin irritation or adverse events were reported in the human study. CONCLUSIONS: The addition of a film-forming copolymer has the potential to improve the retention of CHG on skin throughout a surgical procedure compared to a water-soluble preparation. This improved retention may lead to better antimicrobial activity.

Measurements of chlorhexidine, p-chloroaniline, and p-chloronitrobenzene in saliva after mouth wash before and after operation with 0.2% chlorhexidine digluconate in maxillofacial surgery: a randomised controlled trial.

Chlorhexidine gluconate is used to prevent the accumulation of dental plaque and gingivitis, infection of the surgical site, and ventilator-associated pneumonia in maxillofacial surgery, but it is not clear whether the metabolites of chlorhexidine are detectable in the patient's saliva at clinically relevant concentrations. Forty-three patients who had orofacial operations were randomised to use a 0.2% chlorhexidine gluconate (n=23), or an octenidine-based, chlorhexidine-free (n=20), mouthwash once preoperatively and three times daily for five postoperative days. After the first, 8.7 (23.3) mg/L chlorhexidine (0.7%-2.5% of the total amount used) was measured in saliva. The concentration increased to 15.2 (6.2) mg/L after the second rinse (first postoperative day), and peaked at 29.4 (11.2) mg/L on the fourth postoperative day. It remained detectable for up to 12hours after the last one, but was not detectable in serum or urine at any time. The potentially carcinogenic metabolite p-chloroaniline was detectable in saliva at higher concentrations in the chlorhexidine group (0.55mg/L) than the octenidine group (0.21mg/L), and p-chloronitrobenzene was detected in both groups in only minimal concentrations (0.001-0.21mg/L). Chlorhexidine gluconate mouthwashes do increase the concentration of p-chloroaniline, but a single use seems to be safe. Whether prolonged exposure over many years may have carcinogenic potential is still not clear. Based on the hitherto unknown kinetics of p-chloroaniline in saliva, the recent recommendation of the Federal Drug Administration (FDA) in the USA to limit the use of a chlorhexidine gluconate mouthwash to a maximum of six months seems to be justified.

Efficacy of ethylene-diamine-tetra-acetic acid associated with chlorhexidine on intracanal medication removal: a scanning electron microscopy study.

The aim of this study was to evaluate the effectiveness of 17% ethylene-diamine-tetra-acetic acid (EDTA) used alone or associated with 2% chlorhexidine gel (CHX) on intracanal medications (ICM) removal. Sixty single-rooted human teeth with fully formed apex were selected. The cervical and middle thirds of each canal were prepared with Gates Glidden drills and rotary files. The apical third was shaped with hand files. The specimens were randomly divided into two groups depending on the ICM used after instrumentation: calcium hydroxide Ca(OH)(2) +CHX or Ca(OH)(2) +sterile saline (SS). After seven days, each group was divided into subgroups according to the protocol used for ICM removal: instrumentation and irrigation either with EDTA, CHX+EDTA, or SS (control groups). All specimens were sectioned and processed for observation of the apical thirds by using scanning electron microscopy. Two calibrated evaluators attributed scores to each specimen. The differences between the protocols for ICM removal were analyzed with Kruskal-Wallis and Mann-Whitney U tests. Friedman and Wilcoxon signed rank tests were used for comparison between the score of debris obtained in each root canal third. Remains of Ca(OH)(2) were found in all specimens independently of the protocol and ICM used (P > 0.05). Seventeen percent EDTA showed the best results in removing ICM when used alone (P < 0.05), particularly in those associated with CHX. It was concluded that the chelating agent 17% EDTA significantly improved the removal of ICM when used alone. Furthermore, the type of the vehicle associated with Ca(OH)(2) also plays a role in the ICM removal.

Determination of chemical components derived from 2% chlorhexidine gel degradation using gas chromatography-mass spectrometry.

OBJECTIVE: This study determined the chemical components derived from degradation of 2% chlorhexidine (CHX) gel and solution by using gas chromatography-mass spectrometry. MATERIALS AND METHODS: Three 2% CHX gels were used to identify the products of CHX gel degradation using gas chromatography-mass spectrometry. A solution of CHX was also evaluated to compare the degradation between gel and solution. Degradation was evaluated in four storage situations (on the worktable with light: on the worktable without light; in the Pasteur oven at 36.5°C without light; and in the refrigerator at 8°C without light). Measurements were made at four time points: initial analysis and 1, 3 and 6 months after. The conversion of CHX into para-chloroaniline in storage situations and in different periods was analyzed statistically using chi-square test (α = 5%). RESULTS: The 2% CHX gel or solution had already degraded vial found within the period of validity, at all time points and for all storage conditions. The amount of para-chloroaniline (pCA) was directly proportional to time in the case of CHX solution, but not in CHX gel due to lack of homogeneity. CHX homogeneity in hydroxyethylcellulose gel was directly dependent on compounding mode. CONCLUSIONS: Degradation products, such as para-chloroaniline (pCA), orto- chloroaniline (oCA), meta-chloroaniline (mCA), reactive oxygen species (ROS) and organochlorines (ortho-chlorophenyl isocyanate and 2-amino-5-clorobenzonitrila) were found in 2% CHX gel and solution, regardless of storage conditions or time. In relationship to gel homogenization an alternative to produce 2% CHX gel and a new homogenization method have been developed.

Development and validation of a microbiological assay for determination of chlorhexidine digluconate in aqueous solution

Chlorhexidine (CHX) is a broad-spectrum antiseptic that is used in many topical pharmaceutical formulations. Because there is no official microbiological assay reported in the literature that is used to quantify CHX, this paper reports the development and validation of a simple, sensitive, accurate and reproducible agar diffusion method for the dosage of chlorhexidine digluconate (CHX-D) in an aqueous solution. The assay is based on the inhibitory effect of CHX-D upon the strain of Staphylococcus aureus ATCC 25923, which is used as the test microorganism. The design 3x3 parallel-line model was used. The results were treated statistically by analysis of variance (ANOVA), and they were excellent in terms of linearity (r = 0.9999), presenting a significant regression between the zone diameter of growth inhibition and the logarithm of the concentration within the range of 0.5 to 4.5%. The results obtained were precise, having relative standard deviations (RSD) for intra-day and inter-day precision of 2.03% and 2.94%, respectively. The accuracy was 99.03%. The method proved to be very useful and appropriate for the microbiological dosage of CHX-D in pharmaceutical formulations; it might also be used for routine drug analysis during quality control in pharmaceutical industries.

Clorexidina (CHX) é um antisséptico com amplo espectro de ação utilizada em muitos tipos de preparações farmacêuticas para uso tópico. Uma vez que não há na literatura ensaio microbiológico oficial para quantificar a clorexidina, este trabalho objetivou o desenvolvimento e validação de um ensaio microbiológico simples, sensível, exato e reprodutível, por difusão em ágar, para doseamento de digliconato de clorexidina (CHX-D) em solução aquosa. O ensaio é baseado no efeito da inibição de Staphylococcus aureus ATCC 25923, utilizado como microorganismo teste, pela CHX-D. Utilizou-se o delineamento 3x3. Os resultados foram verificados estatisticamente pela análise de variância (ANOVA) e apresentaram excelente linearidade (r = 0,9999), demonstrando que o método segue o modelo linear com regressão significativa entre o diâmetro da zona de inibição e o lagaritmo da concentração no intervalo de 0,5 a 4,5%. Os resultados obtidos foram precisos apresentando desvio padrão relativo (DPR) para precisão intra-dia de 2,03% e DPR para precisão inter-dias de 2,94%. A exatidão foi 99,03%. O método provou ser muito útil e apropriado para doseamento microbiológico da CHX-D em formas farmacêuticas e pode ser empregado para análise desta substância no controle de qualidade em indústrias farmacêuticas.

Chlorhexidine: beta-cyclodextrin inhibits yeast growth by extraction of ergosterol

Chlorhexidine (Cx) augmented with beta-cyclodextrin (β-cd) inclusion compounds, termed Cx:β-cd complexes, have been developed for use as antiseptic agents. The aim of this study was to examine the interactions of Cx:β-cd complexes, prepared at different molecular ratios, with sterol and yeast membranes. The Minimal Inhibitory Concentration (MIC) against the yeast Candida albicans (C.a.) was determined for each complex; the MICs were found to range from 0.5 to 2 µg/mL. To confirm the MIC data, quantitative analysis of viable cells was performed using trypan blue staining. Mechanistic characterization of the interactions that the Cx:β-cd complexes have with the yeast membrane and assessment of membrane morphology following exposure to Cx:β-cd complexes were performed using Sterol Quantification Method analysis (SQM) and scanning electron microscopy (SEM). SQM revealed that sterol extraction increased with increasing β-cd concentrations (1.71 × 10³; 1.4 × 10³; 3.45 × 10³, and 3.74 × 10³ CFU for 1:1, 1:2, 1:3, and 1:4, respectively), likely as a consequence of membrane ergosterol solubilization. SEM images demonstrated that cell membrane damage is a visible and significant mechanism that contributes to the antimicrobial effects of Cx:β-cd complexes. Cell disorganization increased significantly as the proportion of β-cyclodextrin present in the complex increased. Morphology of cells exposed to complexes with 1:3 and 1:4 molar ratios of Cx:β-cd were observed to have large aggregates mixed with yeast remains, representing more membrane disruption than that observed in cells treated with Cx alone. In conclusion, nanoaggregates of Cx:β-cd complexes block yeast growth via ergosterol extraction, permeabilizing the membrane by creating cluster-like structures within the cell membrane, possibly due to high amounts of hydrogen bonding.

Adsorption of chlorhexidine on synthetic hydroxyapatite and in vitro biological activity.

The kinetic of chlorhexidine digluconate (CHXDG) uptake from aqueous solution by hydroxyapatite (HA) was investigated by ultraviolet (UV) analysis performed in HA powder (UV-solid) after the CHX adsorption. Adsorption isotherm of chlorhexidine (CHX) uptake was modeled by a combination of Languimir and Langmuir-Freundlich mechanisms. Strong molecule-molecule interactions and positive cooperativity predominated in the surface when CHX concentration was above 8.6 µg(CHX)/mg(HA). UV-solid spectra (shape, intensity and band position) of CHX bound to HA revealed that long-range molecular structures, such as aggregates or micelles, started to be formed at low CHX concentrations (1.52 µg(CHX)/mg(HA)) and predominated at high concentrations. Grazing-incidence X-ray diffraction (GIXRD) analysis from synchrotron radiation discarded the formation of crystalline structures on HA surface or precipitation of CHX crystalline salts, as suggested in previous works. The effect of the HA/CHX association on HA in vitro bioactivity, cytotoxicity and CHX antimicrobial activity was evaluated. It was shown that CHX did not inhibit the precipitation of a poorly crystalline apatite at HA/CHX surface after soaking in simulating body fluid (SBF). Cell viability studies after exposure to extracts of HA and HA/CHX showed that both biomaterials did not present significant in vitro toxicity. Moreover, HA/CHX inhibited Enterococcus faecalis growth for up to 6 days, revealing that binding to HA did not affect antimicrobial activity of CHX and reduced bacterial adhesion. These results suggested that HA/CHX association could result in a potential adjuvant antimicrobial system for clinical use.

Vernix caseosa as a multi-component defence system based on polypeptides, lipids and their interactions.

Vernix caseosa is a white cream-like substance that covers the skin of the foetus and the newborn baby. Recently, we discovered antimicrobial peptides/proteins such as LL-37 in vernix, suggesting host defence functions of vernix. In a proteomic approach, we have continued to characterize proteins in vernix and have identified 20 proteins, plus additional variant forms. The novel proteins identified, considered to be involved in host defence, are cystatin A, UGRP-1, and calgranulin A, B and C. These proteins add protective functions to vernix such as antifungal activity, opsonizing capacity, protease inhibition and parasite inactivation. The composition of the lipids in vernix has also been characterized and among these compounds the free fatty acids were found to exhibit antimicrobial activity. Interestingly, the vernix lipids enhance the antimicrobial activity of LL-37 in vitro, indicating interactions between lipids and antimicrobial peptides in vernix. In conclusion, vernix is a balanced cream of compounds involved in host defence, protecting the foetus and newborn against infection.

Chlorhexidine substantivity in root canal dentin.

OBJECTIVE: The purpose of this investigation was to evaluate the substantivity of chlorhexidine (CHX) within a root canal system and to assess how long the CHX remains antimicrobially effective. STUDY DESIGN: Bovine roots were sectioned and standardized to 8 mm. Sections, which served as controls, were treated with 1% sodium hypochlorite and 1 mol/L EDTA, then obturated with gutta percha and AH26 sealer. Experimental sections were treated similarly except they were placed in 2% CHX for 10 minutes prior to obturation. Control specimens were divided into 4 control groups and stored in saline for 1 day, 3 weeks, 6 weeks, and 12 weeks. Experimental specimens were divided into 4 groups and stored in saline for 1 day, 3 weeks, 6 weeks, and 12 weeks. After their respective storage periods, all specimens were halved and canal wall dentin was ground out with Peeso reamers. Dentin specimens were agitated in 700 microl of saline for 5 hours to release CHX. After centrifugation the supernatants were analyzed with UV spectrophotometry at 253 nm. To determine whether the CHX from dentin samples remained antimicrobial, the extracts from experimental and control groups were mixed with cultures of Enterococcus faecalis. RESULTS: After 1 day of storage, the dentin extract contained approximately 0.0048% CHX. After 3, 6 and 12 weeks, dentin extracts contained approximately 0.0023%, 0.0016%, and 0.0010% CHX respectively. Extracts from the storage groups were found to be highly antimicrobial corresponding to the CHX concentration. CONCLUSION: The results of this study indicate that CHX is retained in root canal dentin in antimicrobially effective amounts for up to 12 weeks.

Candida sp in the oral cavity with and without lesions: maximal inhibitory dilution of propolis and periogard

Fifty individuals of both sexes aged on average 45.2 years were evaluated at the Semiology Clinic of FORP-USP in order to isolate and identify yeasts from the oral cavity, with and without lesions, and to determine the maximal inhibitory dilution (MID) of the commercial products Propolis (Apis-Flora) and Periogard (Colgate) against the strains isolated. Yeasts of the genus "Candida" were detected in the saliva of 9.19 (47.4(per cent)) individuals with clinically healthy mouth, 18/22 (81.8(per cent)) of individuals with oral lesions, and in 4/9 (44.4(per cent)) of patients with deviation from normality, and were detected in 19/22 (86.4(per cent)) of the lesions. In the group with oral candidiasis, we isolated in tongue and lesion, respectively for each specie: "C. tropicalis" (8(per cent) and 10.7(per cent)), "C. glabrata" (4(per cent)) and 3.6(per cent)) and "C. parapsilosis" (2(per cent) and 3.6(per cent)), in addition to "C. albicans" (71.4(per cent) and 67.8(per cent)) as the only species and the prevalent. The total cfu counts/ml saliva showed a higher mean value in the group with oral candidiasis (171.5E+3) than in the control group (72.6E+3) or the group with abnormalities (8.3E+3). Most of the test strains 67/70 (95.71(per cent)) were sensitive to the antiseptics, with Propolis presenting a MID of 1:20 for 54/70/77.1(per cent)), and Periogard a MID of 1:160 for 42/70 (60(per cent)) strains from healthy sites, results similar to those obtained with strains from oral lesions. Different results were mainly observed among different species. The results indicate the possibility of using the antiseptics Propolis and Periogard (chlorhexidine) for the prevention and treatment of oral candidiasis

High-performance liquid chromatographic analysis of chlorhexidine in saliva after mouthrinsing.

A high-performance liquid chromatographic method was developed to quantify chlorhexidine in human saliva. After addition of an internal standard and acidic-deproteinization, saliva samples were chromatographed by the reversed-phase ion-pair system using pentanesulfonate as a counterion and the eluates were detected by a diode array detector. Under optimal conditions, the baseline separation of analytes was achieved within 4.5 min without interference from components in saliva matrix. The method showed high selectivity to salivary chlorhexidine, quantitative range (50. 0ng/ml-50.0 microg/ml), recovery (96.0-97.8%) and analytical precision (intra- and interassay CVs within 0.41%), permitting the effective application to both saliva and aqueous solutions. Chlorhexidine was found in saliva at microgram per milliliter levels for at least 8 h after mouthrinsing with 10 ml of an aqueous solution of chlorhexidine (0.1 or 1.0 mg/ml) for 1 min. The concentrations of salivary chlorhexidine were reduced by ingesting the acidic beverage and food, but not by ingesting the neutral beverage. The adsorption experiments in artificial saliva revealed that chlorhexidine was significantly adsorbed to saliva-coated hydroxyapatite, buccal epithelial cells and mucin. The proposed method will be a useful tool to study salivary chlorhexidine after oral application and its retention in the oral cavity.

Biocompatibilidade das soluçöes de iodo polivinilpirrolidona (PVP-1) e de clorexidina: estudo histológico em ratos / Biocompatibility study of 1-PVP and chlorhexidine solutions: histological study on rats

O objetivo deste trabalho foi analisar a reaçäo do tecido conjuntivo subcutâneo em contato com tubos de polietileno preenchidos com soluçäo de iodo polivinilpirrolidona tópico (PVP-1) a 1 por cento e clorexidina a 0,2 por cento e soro fisiológico no seu interior. Os animais foram sacrificados aos 3, 5, 10, 30 e 60 dias pós-operatórios. Os resultados obtidos permitiram concluir que: os grupos apresentaram diferenças estatisticamente significantes entre si, podendo ser ordenados, do que apresentou melhor para o que apresentou pior biocompatibilidade: 1. Grupo soro fisiológico/ 2. Grupo Clorexidina/ 3. Grupo PVP-1

Influência de bochechos com soluçöes de digluconato de clorexidina a 0,2 por cento, fluoreto de sódio a 0,05 por cento pH 3,4 e esteviosídeo a 0,1 por cento, na inibiçäo da placa dentária "in vivo", em crianças / Influence of the mouthrinses with 0,2 percent chlorhexidine digluconate, 0,05 percent sodium fluoride pH 3,4 and 0,1 by cent stevioside, in the inhibition of dental plaque \"in vivo\", in children

Foi avaliado o efeito de bochechos diários com digluconato de clorexidina a 0,2 por cento, fluoreto de sódio a 0,05 por cento pH 3,4 e esteviosídeo a 0,1 por cento, sobre a inibiçäo do acúmulo de placa dentária em crianças e verificado os efeitos colaterais das soluçöes, assim como a aceitaçäo das mesmas. Para tanto, 200 crianças entre 7 e 11 anos de idade foram divididas em 4 grupos, sendo um controle (água deionizada) e 3 experimentais, utilizando-se para avaliaçäo clínica o índice de placa LOE. As crianças executaram bochechos diários com 5 ml de soluçäo por 1 minuto, sob supervisäo, durante um período de 6 semanas. Concluiu-se que todas as substâncias testadas apresentaram inibiçäo de placa bacteriana, com reduçäo de 52,63 por cento para o digluconato de clorexidina a 0,2 por cento, 39,34 por cento para o fluoreto de sódio a 0,05 por cento pH 3,4 e 30,60 por cento para o esteviosídeo a 0,1 por cento. Todas as soluçöes experimentais foi mais relatado para o digluconato de clorexidina a 0,2 por cento e a pigmentaçäo dentária observada apenas com a utilizaçäo dessa substância

Gas chromatographic determination of p-chloroaniline in a chlorhexidine digluconate-containing alcohol foam surgical scrub product.

A gas chromatographic (GC) method with flame ionization detection was developed to separate and quantitate p-chloroaniline (PCA) from other components in a chlorhexidine digluconate (CHG)-containing alcohol foam surgical scrub product. A simple sample preparation method was developed in which 1-butanol was used to dissolve the foam and precipitate the CHG, which otherwise would interfere with the GC analysis. The method was validated with respect to linear dynamic range, precision, accuracy, selectivity, limit of detection, and limit of quantitation.

Actividad in vitro de la clorhexidina frente a cepas de acinetobacter baumannii / In vitro activity of chlorhexidine against strains of acinetobacter baumannii

Se evaluó la actividad inhibitoria del crecimiento y actividad bactericida in vitro del gluconato de clorhexidina frente a 62 cepas de Acinetobacter baumannii multirresistente a los antibióticos. Concentraciones de la droga entre 0,4 y 40 *g/ml inhibieron el crecimiento de la totalidad de las cepas. Las CIMs fueron 40 *g/ml para 40 (64,5%) cepas, 4 *g/ml para 21 (33,9%) de ellas y 0,4 *g/ml para 1 cepa (1,6%). Actividad bactericida de la clorhexidina fue obtenida a concentraciones entre 40 y 400 *g/ml y en la mayoría de las cepas dentro de los primeros 5 minutos de contacto con el antiséptico. Los resultados indican una eficiente actividad antimicrobiana in vitro de la clorhexidina frente a este microorganismo

Efeito da aplicaçäo tópica de agentes antimicrobianos sobre a inibiçäo da placa dentária "in vivo" em crianças e em ratos (Rattus novergicus, var-albinus) / Effect of topical application of antimicrobial agents on dental plaque inhibition \"in vivo\" in children and in rats (Rattus novergicus, var-albinus)

O presente trabalho avaliou através de 2 modelos de estudo, um em crianças outro em ratos, a capacidade dos mesmos demonstrarem as diferenças entre vários agentes antimicrobianos, quanto ao seu poder de inibir placa. As soluçöes utilizadas nos 2 estudos foram as mesmas: G.I - Água Deionizada (controle); G.II - Digluconato de Clorexidina (2 por cento); G.III - Fluoreto Estanoso (0,6 por cento); G.IV - C.C.P. (1,36 por cento); G.V - C.C.P. (1,36 por cento) com Sulfato de Cobre (1,0 por cento). No experimento com crianças, desenvolvido em 4 semanas as soluçöes foram aplicadas topicamente, 1 vez por semana, durante 1 minuto, sob isolamento relativo, na boca toda. Após cada aplicaçäo era solicitado à criança para näo comer ou beber por 30 minutos. A amostra constou de 144 crianças, entre 7 e 11 anos de idade, divididas em 5 grupos de estudo de acordo com o índice de placa de LOE 65, realizado no início da pesquisa. Elas receberam uma profilaxia profissional inicial, imediatamente antes da 1ª aplicaçäo tópica, e mantiveram seus hábitos de higiene bucal usuais, durante todo o período experimental. Ao final do estudo a placa foi novamente avaliada, pelo mesmo índice, por 2 examinadores calibrados que em seguida realizaram a profilaxia final. A análise dos dados obtidos permitiu concluir que: - Todos os tratamentos provocaram reduçöes do I.P.F. para a boca toda, em relaçäo ao I.P.I., sendo a reduçäo de placa maior para o G.II (clorexidina), seguida do G.V (C.C.P. mais sulfato de cobre), do G.IV (C.C.P.) e do G.III (fluoreto estanoso). A pequena reduçäo do I.P.F. observada no G.I, revelou que näo houve efeito placebo da escovaçäo; - Os resultados obtidos no G.II e G.V foram estatisticamente significantes, quando comparados ao G.III e G.IV, tanto para a boca toda como para a regiäo de molares. Entretanto, quando comparados o G.II com o G.V e, G.III com o G.IV näo houve significância estatística. Já para a regiäo dos incisivos, a significância estatística ocorreu somente entre os G.IV e G.V...

[Toxic impurities in chlorhexidine digluconate]. / Toxische Verunreinigungen in Chlorhexidin-digluconat.

Three preparations of chlorhexidine-digluconate were analysed for contamination with a newly developed high-pressure liquid chromatographic method. Of special interest was p-chloroaniline, a toxic as well as a carcinogenic compound. We found concentrations from 1.7 to 8.5 mmol p-chloroaniline per mol chlorhexidine-digluconate, i.e. five-fold differences in the different products. Besides p-chloroaniline many other contaminating substances were found, amongst others p-chlorophenyl-isocyanate and p-chlorophenyl-carbodiimide. The least contamination was found in a branded article, and the highest degree of contamination in a "no-name"-product. During a storage period of half a year in dark glass bottles in a solution of 0.2% under various light and temperature values the p-chloroaniline concentrations increased linearly with the period of storage, with the exception of storage in the dark at 5 degrees C. A constant temperature of 35 degrees C in the dark caused a greater increase than storing at 20-25 degrees C in the dark or the light or in direct sunlight. Therefore under similar conditions it is mostly warmth which causes an increase in toxic compounds.