Aqueous Chlorhexidine Compared with Povidone-Iodine as Ocular Antisepsis before Intravitreal Injection: A Randomized Clinical Trial

PURPOSE

Topical povidone-iodine (PI) is widely used as an ocular surface antiseptic for intravitreal injections (IVIs). Although PI is generally well tolerated, it can be associated with significant ocular irritation. Aqueous chlorhexidine (AqCHX) has been described as a possibly better tolerated antimicrobial for ophthalmic procedures. We compared patient pain scores, ocular surface characteristics, and antimicrobial efficacy between PI 5% and AqCHX 0.1% during IVIs.

DESIGN

Prospective single-center, randomized clinical trial.

PARTICIPANTS

Patients receiving same-day bilateral intravitreal anti-vascular endothelial growth factor (VEGF) injections.

METHODS

Each patient had 1 eye randomized to PI or AqCHX, and the second eye received the other agent. Both eyes received topical proparacaine 0.5%.

MAIN OUTCOME MEASURES

After IVIs, participants rated their pain (Wong-Baker, scale 0-10) for each eye 1 minute after PI or AqCHX instillation and 1 day after the procedure. Each eye was assessed using a standardized quantitative grading system of corneal epitheliopathy (ocular staining score). Microbial swab cultures of the conjunctiva both before instillation of topical antisepsis and 10 minutes after IVIs were given.

RESULTS

A total of 100 eyes of 50 patients were included. The mean patient age was 68 years (range, 39-92), and 30 of 50 (60%) were male. Compared with AqCHX, eyes receiving PI had a greater mean pain score immediately after injection (1.44 vs. 0.44, P < 0.001) but not on postprocedure day 1 (1.04 vs. 0.48, P = 0.06). Eyes that received PI had a higher ocular staining score indicating worse corneal epitheliopathy (4.22 vs. 3.10, P < 0.001). There was no difference in rates of positive microbial cultures between groups. There was no difference in rates of adverse events between groups (P = 0.99), and no cases of endophthalmitis occurred.

CONCLUSIONS

Povidone-iodine demonstrated greater ocular surface discomfort and corneal epitheliopathy compared with AqCHX during same-day bilateral IVIs. The 2 agents otherwise demonstrated no difference in positive microbial cultures or adverse events. Aqueous chlorhexidine may be a better tolerated alternative to PI for antimicrobial prophylaxis during IVIs for some patients.

Biomarkers for the toxicity of sublethal concentrations of triclosan to the early life stages of carps

Accumulation, contents of protein, non-enzymatic antioxidant glutathione (GSH and GSSG), lipid peroxidation product (melondialdehyde-MDA) and organic acids (fumarate, succinate, malate and citrate), and activities of neurological (acetylcholinesterase-AChE), detoxification (glutathione S-transferase-GST) and metabolic (lactate dehydrogenase-LDH, aspartate transaminase-AST and alanine transaminase-ALT) enzymes were recorded in the hatchlings of Cyprinus carpio, Ctenopharyngodon idella, Labeo rohita and Cirrhinus mrigala after 7 and 14 days exposure and 10 days post exposure (recovery period) to sublethal concentrations (0.005, 0.01, 0.02 and 0.05 mg/L) of triclosan, a highly toxic and persistent biocide used in personal care products. Accumulation was maximum between 7-14 days at 0.01 mg/L for C. carpio and L. rohita but at 0.005 mg/L for C. idella and C. mrigala. No triclosan was observed at 0.005 mg/L in C. carpio and C. mrigala after recovery. Significant decline in protein, glutathione and acetylcholinesterase but increase in glutathione S-transferase, lactate dehydrogenase, aspartate transaminase, alanine transaminase, melondialdehyde and organic acids over control during exposure continued till the end of recovery period. Integrated biomarker response (IBR) analysis depicted higher star plot area for glutathione and glutathione S-transferase during initial 7 days of exposure, thereafter, during 7-14 days of exposure and the recovery period, higher star plot area was observed for acetylcholinesterase, aspartate transaminase, alanine transaminase and organic acids. Higher star plot area was observed for protein in all the species throughout the study. The study shows that L. rohita is most sensitive and glutathione, acetylcholinesterase, aspartate transaminase and alanine transaminase are the biomarkers for the toxicity of sublethal concentrations of TCS.

Minimal effective dose of povidone-iodine in abdominal surgery Our clinical experience

The aim of this study is to evaluate the thyroid function tests in order to examine whether 10 % of Povidone-Iodine(PI), the medication we applied in 1/5 ratio diluted with 0.9 %NaCl, joins the systemic circulation during clean contaminated, contaminated and dirty operations for solid organ hydatid cysts in abdominal area to avoid abscess formation and spreading. 7 men and 6 women were included to the present study, prospectively. The mean age was 33.69(± 13.49). TSH, free T3 (fT3) and free T4 (fT4) hormone levels were measured before the operation and at the third day of postoperative period. Amount of used povidone-iodine for patients was recorded. As a result of statistical analysis applied, the preoperative and post operative values were not significantly different regarding with the measured hormone levels (preTSH vs postTSH: p= 0.984; prefT3 vs postfT3: p= 0.101; prefT4 vs postfT4: p=0.146). Thus, it has been shown that the dose we used is effective, and it does not enters at all or at quite low levels into the systemic circulation. Patients whom this application performed, abscess and intestinal adhesions have not been observed in our clinical experience. We recommend the use of suggested doses of Povidone-Iodine in the presence of intraabdominal perforation and abscess or in cases such as carrying a risk of cyst spreading to intraabdominal area in hydatid cysts.

KEY WORDS

Povidone-iodine, Surgical adhesions, Surgical wound infections, Thyroid function tests.

Antimicrobial functionalization of bacterial nanocellulose by loading with polihexanide and povidone-iodine

Bacterial nanocellulose (BNC) is chemically identical with plant cellulose but free of byproducts like lignin, pectin, and hemicelluloses, featuring a unique reticulate network of fine fibers. BNC sheets are mostly obtained by static cultivation. Now, a Horizontal Lift Reactor may provide a cost efficient method for mass production. This is of particular interest as BNC features several properties of an ideal wound dressing although it exhibits no bactericidal activity. Therefore, BNC was functionalized with the antiseptics povidone-iodine (PI) and polihexanide (PHMB). Drug loading and release, mechanical characteristics, biocompatibility, and antimicrobial efficacy were investigated. Antiseptics release was based on diffusion and swelling according to Ritger-Peppas equation. PI-loaded BNC demonstrated a delayed release compared to PHMB due to a high molar drug mass and structural changes induced by PI insertion into BNC that also increased the compressive strength of BNC samples. Biological assays demonstrated high biocompatibility of PI-loaded BNC in human keratinocytes but a distinctly lower antimicrobial activity against Staphylococcus aureus compared to PHMB-loaded BNC. Overall, BNC loaded with PHMB demonstrated a better therapeutic window. Moreover, compressive and tensile strength were not changed by incorporation of PHMB into BNC, and solidity during loading and release could be confirmed.

Design and construction of a silver(I)-loaded cellulose-based wound dressing: trackable and sustained release of silver for controlled therapeutic delivery to wound sites

Although application of silver nitrate and silver sulfadiazine have been shown to be effective in thwarting infections at burn sites, optimization of the delivery of bioactive silver (Ag(+)) remains as an obstacle due to rapid precipitation and/or insolubility of the silver sources. To circumvent these shortcomings, we have designed a silver(I) complex [Ag(ImD)2]ClO4 (ImD = dansyl imidazole) that effectively increases the bioavailability of Ag(+) and exhibits MIC values of 2.3 and 4.7 μg/mL against E. coli and S. aureus, respectively. This fluorescent silver complex has been incorporated within a robust hydrogel derived from carboxymethyl cellulose that allows slow release of silver. A complete occlusive dressing has finally been constructed with the Ag(ImD)CMC (1% Ag loaded) pad sealed between a sterile mesh gauze (as bottom layer) and a rayon-based surgical tape (as the top layer). Such construction has afforded a dressing that displays sustained delivery of silver onto a skin and soft tissue infection model and causes effective eradication of bacterial loads within 24 h. The transfer of the bioactive silver complex is readily visualized by the observed fluorescence that overlays precisely with the kill zone. The latter feature introduces a unique feature of therapeutic trackability to this silver-donating occlusive dressing.

Chlorhexidine--pharmaco-biological activity and application

OBJECTIVES

Chlorhexidine (CHX) is one of the most widely used antiseptic, especially in dentistry. At low concentrations CHX is bacteriostatic and at high concentrations acts bactericidal causing cell death by cytolysis. In this study, we performed a systematic review of pharmaco-biological activity and application of CHX.

MATERIALS AND METHODS

Articles for inclusion in this review were retrieved from online databases PubMed/Medline. The selected papers were included in the present manuscript according to their relevance for the topic.

RESULTS

Totally 75 papers were enrolled in this research. CHX has strong biocidal activity against Gram-positive bacteria and weaker activity against Gram-negative bacteria. It is also active against yeasts, some dermatophytes and some lipophilic viruses. The most widely application CHX has found in dentistry and antisepsis. Numerous studies have confirmed the beneficial effects of CHX in reducing of plaque accumulation, in tooth caries, gingivitis, periodontitis and in alveolar osteitis. Unfortunately, CHX exhibits cytotoxic activity on human cells, can cause colorization of teeth and fillings, and its activity depends on the pH of the environment and the presence of organic substances.

CONCLUSIONS

CHX play a valuable role in the dentistry and antisepsis. However, it can also cause side effects, limiting its application time.

Novel high efficient coatings for anti-microbial surgical sutures using chlorhexidine in fatty acid slow-release carrier systems

Sutures can cause challenging surgical site infections, due to capillary effects resulting in bacteria permeating wounds. Anti-microbial sutures may avoid these complications by inhibiting bacterial pathogens. Recently, first triclosan-resistances were reported and therefore alternative substances are becoming clinically relevant. As triclosan alternative chlorhexidine, the “gold standard” in oral antiseptics was used. The aim of the study was to optimize novel slow release chlorhexidine coatings based on fatty acids in surgical sutures, to reach a high anti-microbial efficacy and simultaneously high biocompatibility. Sutures were coated with chlorhexidine laurate and chlorhexidine palmitate solutions leading to 11, 22 or 33 µg/cm drug concentration per length. Drug release profiles were determined in aqueous elutions. Antibacterial efficacy against Staphylococcus aureus was assessed in agar diffusion tests. Biocompatibility was evaluated via established cytotoxicity assay (WST-1). A commercially triclosan-containing suture (Vicryl Plus), was used as anti-microbial reference. All coated sutures fulfilled European Pharmacopoeia required tensile strength and proved continuous slow drug release over 96 hours without complete wash out of the coated drug. High anti-microbial efficacy for up to 5 days was observed. Regarding biocompatibility, sutures using 11 µg/cm drug content displayed acceptable cytotoxic levels according to ISO 10993-5. The highest potential for human application were shown by the 11 µg/cm chlorhexidine coated sutures with palmitic acid. These novel coated sutures might be alternatives to already established anti-microbial sutures such as Vicryl Plus in case of triclosan-resistance. Chlorhexidine is already an established oral antiseptic, safety and efficacy should be proven for clinical applications in anti-microbial sutures.

[The treatment of acute inflammation of the middle ear]

The authors propose the differential approach to the treatment of acute inflammation of otitis media and otitis externa taking into consideration etiology of the disease. Its clinical form and stage. Special attention is given to the method of local treatment including the use of various eardrops. The results of their comparative assessment are presented.

Measuring dilution of microbicide gels with optical imaging

We present a novel approach for measuring topical microbicide gel dilution using optical imaging. The approach compares gel thickness measurements from fluorimetry and multiplexed low coherence interferometry in order to calculate dilution of a gel. As a microbicide gel becomes diluted at fixed thickness, its mLCI thickness measurement remains constant, while the fluorimetry signal decreases in intensity. The difference between the two measurements is related to the extent of gel dilution. These two optical modalities are implemented in a single endoscopic instrument that enables simultaneous data collection. A preliminary validation study was performed with in vitro placebo gel measurements taken in a controlled test socket. It was found that change in slope of the regression line between fluorimetry and mLCI based measurements indicates dilution. A dilution calibration curve was then generated by repeating the test socket measurements with serial dilutions of placebo gel with vaginal fluid simulant. This methodology can provide valuable dilution information on candidate microbicide products, which could substantially enhance our understanding of their in vivo functioning.

Metabolization of the bacteriostatic agent triclosan in edible plants and its consequences for plant uptake assessment

Persistent environmental contaminants may enter agricultural fields via the application of sewage sludge, by irrigation with treated municipal wastewater or by manuring. It has been shown that such contaminants can be incorporated into crop plants. The metabolism of the bacteriostatic agents triclocarban, triclosan, and its transformation product methyl triclosan was investigated after their uptake into carrot cell cultures. A fast metabolization of triclosan was observed and eight so far unknown phase II metabolites, conjugates with saccharides, disaccharides, malonic acid, and sulfate, were identified by liquid chromatography-mass spectrometry. Triclocarban and methyl triclosan lack a phenolic group and remained unaltered in the cell cultures. Phase I metabolization was not observed for any of the compounds. All eight triclosan conjugates identified in the cell cultures were also detected in extracts of intact carrot plants cultivated on triclosan contaminated soils. Their total amount in the plants was assessed to exceed the amount of the triclosan itself by a factor of 5. This study shows that a disregard of conjugates in studies on plant uptake of environmental contaminants may severely underestimates the extent of uptake into plants and, eventually, the potential human exposure to contaminants via food of plant origin.

In vivo evaluation of a metronidazole-containing gel for the adjuvant treatment of chronic periodontitis: preliminary results

The present study developed an experimental metronidazole-based gel and evaluated its efficacy for the adjuvant treatment of chronic periodontitis. Sixteen patients were randomly allocated into two groups of eight subjects according to the following proposed treatments: (1) scaling and root planing (active control) or (2) scaling and root planing and direct periodontal intrapocket application of 15% metronidazole-based gel in two sites (≥5 mm in depth) (experimental group). Potential changes in the subgingival microbiota were assessed using a DNA Checkerboard method at three proposed times: baseline and following 7 or 30 days of drug administration. High-performance liquid chromatography (HPLC) monitored metronidazole concentrations in the crevicular fluid during treatment. The metronidazole experimental group presented lower bacterial counts than the control group at the three evaluated times (p<0.01 for baseline, p<0.001 for 7 or 30 days) when the target species were analyzed as a pool of bacteria. Samples revealed significantly lower counts 7 days after drug administration compared with baseline or after 30 days (p<0.05). HPLC analysis detected gel 1 h after application. The metronidazole-based gel significantly decreased the total bacterial count at the three evaluated times. Periodontopathogenic species were not different after gel administration.

[The use of exogenous nitrogen monoxide for the prophylaxis of postoperative wound infection]

The study covers treatment results of 220 patients operated on ventral hernia and in vivo experimental treatment of 36 rats proved the nitrogen monoxide (NO) to be the effective means of wound infection prophylaxis. NO potentiates antiseptic effects, minimizing intraoperative wound contamination. It, besides, stimulates endothelial and basal cells of epidermis proliferation. Wound infection was observed only in 9,8% of patients, treated with NO intraoperatively. All cases of infective complications were serous and infiltrative, but not purulent.

Conservative management of exomphalos major with silver dressings: are they safe?

Historically, some dressings used in exomphalos major were associated with toxicity. These have been abandoned in favor of safer dressings. Silver toxicity has not been described following the use of silver dressings in infants. We, however, found disconcerting serum silver levels in 2 consecutive patients during treatment with silver salt containing dressings.

Clinical evaluation of microbicide formulations

The clinical evaluation of microbicide formulations presents variable and interacting challenges. Specific domains of acceptability, pharmacokinetics, and toxicity interact with each other to potentially inhibit or enhance a microbicide's efficacy. Each of these is further influenced by application and use parameters in the relative presence (or absence) of vaginal and/or seminal fluids, ultimately impacting effectiveness. Historically, acceptability of formulation and use parameters, and their concomitant behavioral influences, have been considered separately from pharmacokinetics and toxicity. While independent evaluation of these elements is necessary in some respects, we must acknowledge that this approach is not sufficient for the successful development of microbicides. Each needs to be considered in an integrated clinical evaluation strategy. This article presents the rationale for such an approach. This article forms part of a special supplement covering two presentations on clinical evaluation of microbicides from the symposium on "Recent Trends in Microbicide Formulations" held on 25 and 26 January 2010, Arlington, VA.

Effect of dentin treatment time with tetraclean on its residual antibacterial activity

The goal of this study was to evaluate the effect of dentin treatment duration (10 minutes, 24 hours, and seven days) with Tetraclean on its residual antibacterial activity in bovine root dentin. Results showed that the number of colony-forming units in all three experimental groups was zero at the first culture. Furthermore, the 10-minute group and seven-day group demonstrated the highest and the lowest number of colony-forming units, respectively.

A novel injectable chlorhexidine thermosensitive hydrogel for periodontal application: preparation, antibacterial activity and toxicity evaluation

The aim of this paper was to evaluate the application potential of CS-HTCC/GP-0.1%Chx thermosensitive hydrogel which was synthesized using chitosan (CS), quaternized CS, and alpha,beta-glycerophosphate (alpha,beta-GP) loading with 0.1% chlorhexidine (Chx) (w/v) for periodontal treatment. An aqueous solution of CS-HTCC/GP-0.1%Chx was transformed into hydrogel at 6 min when the temperature was increased to 37 degrees C. The scan electron microscopy (SEM) image of the gel was a porous, loose and crosslinked network. In vitro, Chx released over 18 h from the CS-HTCC/GP thermosensitive hydrogel in artificial saliva pH 6.8. Release rate could be controlled through adjustment of alpha,beta-GP or Chx concentration. CS-HTCC/GP-0.1%Chx thermosensitive hydrogel exhibited excellent inhibitory activity against primary periodontal pathogens. CS-HTCC/GP-0.1%Chx thermosensitive hydrogel had no acute toxicity; the maximum tolerated dose in rats was 400 mg/ml. All results indicated that CS-HTCC/GP-0.1%Chx thermosensitive hydrogel is a strong candidate as a local drug delivery system for periodontal treatment.

Chlorhexidine binding to mineralized versus demineralized dentin powder

OBJECTIVES

The purposes of this work were to quantitate the affinity and binding capacity of chlorhexidine (CHX) digluconate to mineralized versus demineralized dentin powder and to determine how much debinding would result from rinsing with water, ethanol, hydroxyethylmethacrylate (HEMA) or 0.5M NaCl in water.

METHODS

Dentin powder was made from coronal dentin of extracted human third molars. Standard amounts of dentin powder were tumbled with increasing concentrations of CHX (0-30 mM) for 30 min at 37 degrees C. After centrifuging the tubes, the supernatant was removed and the decrease in CHX concentration quantitated by UV-spectroscopy. CHX-treated dentin powder was resuspended in one of the four debinding solutions for 3 min. The amount of debound CHX in the solvents was also quantitated by UV-spectroscopy.

RESULTS

As the CHX concentration in the medium increased, the CHX binding to mineralized dentin powder also increased up to 6.8 micromol/g of dry dentin powder. Demineralized dentin powder took up significantly (p<0.01) more CHX, reaching 30.1 micromol CHX/g of dry dentin powder. Debinding of CHX was in the order: HEMA

SIGNIFICANCE

As CHX is not debound by HEMA, it may remain bound to demineralized dentin during resin-dentin bonding. This may be responsible for the long-term efficacy of CHX as an MMP inhibitor in resin-dentin bonds.

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Key Words

• chlorhexidine
• binding
• debinding
• dentin bonding

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MESH Headings

• Anti-Infective Agents, Local/pharmacokinetics
• Anti-Infective Agents, Local/pharmacology
• Chlorhexidine/analogs & derivatives
• Chlorhexidine/pharmacokinetics
• Chlorhexidine/pharmacology
• Collagen/metabolism
• Dental Bonding
• Dentin/metabolism
• Durapatite
• Ethanol
• Humans
• Hydrogen Bonding
• Linear Models
• Matrix Metalloproteinase Inhibitors
• Methacrylates
• Protease Inhibitors/pharmacology
• Protein Binding
• Resin Cements/chemistry
• Sodium Chloride
• Solubility
• Spectroscopy, Fourier Transform Infrared
• Tooth Demineralization/metabolism
• Water

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Grants

• R01 DE015306 NIDCR NIH HHS
• R01 DE015306-06A1 NIDCR NIH HHS
• R01 DE015306-06 NIDCR NIH HHS

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Affiliation(s)

Jongryul Kim Department of Conservative Dentistry, School of Dentistry, Kyung Hee National University, Seoul, Republic of Korea
Toshikazu Uchiyama Department of Regenerative Dentistry, Nihon University School of Dentistry at Matsuso, Chiba, Japan
Marcela Carrilho GEO/UNIBAN, Health Institute, Bandeirante University of São Paulo, Brazil and Department of Dental Materials and Oral Biochemistry, University of São Paulo, School of Dentistry, São Paulo/SP, Brazil
Kelli A. Agee Medical College of Georgia, School of Dentistry, Medical College of Georgia, Augusta, Georgia, USA
Annalisa Mazzoni Department of SAU & FAL, University of Bologna, Bologna, Italy
Lorenzo Breschi Department of Biomedicine, University of Trieste + IGM-CNR, Unit of Bologna, c/o IOR, Bologna, Italy
Ricardo M. Carvalho Department of Operative Dentistry, College of Dentistry, University of Florida, Gainesville, Florida, USA
Leo Tjäderhane Institute of Dentistry, University of Oulu and Oulu University Hospital, Oulu, Finland
Stephen Looney Department of Biostatistics, Medical College of Georgia, Augusta, Georgia, USA
Courtney Wimmer Department of Biostatistics, Medical College of Georgia, Augusta, Georgia, USA
Arzu Tezvergil-Mutluay Department of Prosthodontics, School of Dentistry, University of Turku, Turku, Finland
Franklin R. Tay Department of Endodontics, School of Dentistry, Medical College of Georgia, Augusta, Georgia, USA
David H. Pashley Medical College of Georgia, School of Dentistry, Medical College of Georgia, Augusta, Georgia, USA

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Zinc polycarboxylate dental cement for the controlled release of an active organic substance: proof of concept

The potential of employing zinc polycarboxylate dental cement as a controlled release material has been studied. Benzalkonium chloride was used as the active ingredient, and incorporated at concentrations of 1, 2 and 3% by mass within the cement. At these levels, there was no observable effect on the speed of setting. Release was followed using an ion-selective electrode to determine changes in chloride ion concentration with time. This technique showed that the additive was released when the cured cement was placed in water, with release occurring by a diffusion mechanism for the first 3 h, but continuing beyond that for up to 1 week. Diffusion coefficients were in the range 5.62 x 10(-6) cm(2) s(-1) (for 1% concentration) to 10.90 x 10(-6) cm(2) s(-1) (for 3% concentration). Up to 3% of the total loading of benzalkonium chloride was released from the zinc polycarboxylate after a week, which is similar to that found in previous studies with glass-ionomer cement. It is concluded that zinc polycarboxylate cement is capable of acting as a useful material for the controlled release of active organic compounds.

Maternal and neonatal urinary iodine excretion and neonatal TSH in relation to use of antiseptic during caesarean section in an iodine sufficient area

AIM

To evaluate the influence of topical iodine-containing antiseptics on neonatal TSH in full-term infants born by Caesarean section in an iodine sufficient area.

POPULATION AND METHODS

Urinary iodide excretion (UIE) was estimated in 86 mothers on the second day after delivery by Caesarean section and their 86 full-term neonates. The mothers were divided into two groups according to the use of antiseptic to prepare Cesarean sections: 42 mothers who were prepared with povidone-iodine (Isosept, Bosnalijek) comprised the study group, and 47 mothers who were prepared with alcoholic solution (Skinsept color, Ecolab) formed the control group. Neonatal TSH was measured in whole blood drawn between day 3 and 5 of life, spotted on filter paper using a sensitive fluorometric assay (Delfia).

RESULTS

Maternal and neonatal UIE were significantly higher (p < 0.05) in the study group compared to the control group. No significant difference was found for neonatal TSH.

CONCLUSION

Our data suggest that perinatal iodine exposure of full-term neonates who were born by Caesarean section in an iodine sufficient area did not influence neonatal TSH, although median UIE was higher, suggesting optimal iodine intake during pregnancy. Further research is needed to define a critical value of urinary iodine concentrations in full-term neonates in an iodine sufficient area that may lead to the impairment of thyroid function.

Investigation of triclosan retention and dental plaque viability with a triclosan/PVM/MA copolymer mouthrinse in a Thai population

This investigation studied triclosan retention and plaque viability in a group of healthy human subjects from Bangkok, Thailand, 12 hours after using a mouthrinse containing a triclosan/PVM/MA copolymer system. The results show the retained triclosan in the dental plaque was with in or higher than the minimum inhibitory concentration (MIC range 0.27-6.25 microg/ml), indicating the triclosan in this product remains at an effective concentration in dental plaque. The 12-hour post-application evaluation demonstrated only 36.5% viability of oral bacteria in dental plaque after a one-time use of the mouthrinse. This study shows the benefits of using a mouthrinse containing a triclosan/PVM/MA copolymer system for providing 12 hours long-lasting anti-bacteria and dental plaque control.

Pharmacokinetics and metabolism of acriflavine in rats following intravenous or intramuscular administration of AG60, a mixture of acriflavine and guanosine, a potential antitumour agent

Acriflavine (ACF; CAS 8063-24-9), a mixture of trypaflavine (TRF) and proflavine (PRF) at a ratio of 2:1 is being investigated in rodents as an anticancer agent. However, its pharmacokinetics have not been investigated in mammals. Guanosine is known to potentiate the anticancer activity of some compounds. The pharmacokinetics of AG60, a 1:1 mixture of ACF and guanosine, were therefore investigated in rats. Rats were given 2 or 10 mg kg(-1) AG60 by intravenous bolus or 6 or 30 mg kg (-1) intramuscularly. An HPLC-based method was developed to analyse the levels of TRF, PRF, and their metabolites in plasma, bile, urine and tissue homogenates. The plasma concentrations of TRF and PRF decreased rapidly after intravenous administration and more slowly after intramuscular administration. Both TRF and PRF were distributed widely, most notably in the kidney, and were eliminated slowly. Three glucuronosyl conjugate metabolite peaks were tentatively identified in the bile. The intramuscular route leads to a prolongation of TRF or PRF plasma levels, and the systemic exposures for both TRF and PRF were both relatively high. These observations indicate that the intramuscular route may be the best way to administer AG60 for various clinical applications.

Pharmacokinetics of ruminally dosed sodium [36Cl]chlorate in beef cattle

The recently recognized potential of sodium chlorate as a possible preharvest food safety tool for pathogen reduction in meat animals has spurred interest in the pharmacokinetics of intraruminally dosed chlorate. Six Loala cattle were assigned (one heifer and one steer per treatment) to one of three intraruminal doses of radiolabeled sodium [36Cl]chlorate (21, 42, or 63 mg/kg body weight) administered in four equal aliquots over a 24-h period. Blood and serum were collected (29 samples in 48 h). Total radioactive residues were measured and the radioactive moieties were speciated. Chlorate appeared rapidly in blood and serum after dosing. For animals administered a dose of 42 or 63 mg/kg, the half-life of absorption was estimated at 0.6-0.9 h. Serum chlorate concentrations progressively increased with aliquot administration until peaking at 6-21 parts per million at 26 h. Between aliquot administrations, serum chlorate levels typically peaked in 3.5 h or less. The half-life of chlorate elimination ranged between 6.9 and 11 h, depending on the dose. Ultimately, absorption of chlorate removes it from its desired site of action, the lower gastrointestinal tract, thereby reducing its efficacy. Further research is needed to develop a chlorate formulation that will allow passage to the lower gastrointestinal tract.

Lysostaphin in treatment of neonatal Staphylococcus aureus infection

This study describes lysostaphin's effect against methicillin-sensitive Staphylococcus aureus in suckling rats. Standard techniques determined minimal inhibitory and bactericidal concentrations, pharmacokinetics, and efficacy. The numbers of surviving rats after vancomycin, oxacillin, and lysostaphin treatment were comparable and were different from that of controls (P < 0.00001). Lysostaphin appears effective in the treatment of neonatal S. aureus infection.

Biophysical Analysis of Prototype Microbicidal Gels

The objective of this study was to evaluate the distribution and retention (deployment) of four prototype vehicles for delivery of prophylactic microbicides against vaginal HIV transmission. Study gels were created with different molecular compositions, producing different biophysical properties governing vaginal deployment. The study employed three techniques: direct rheological measurement of gel properties, direct observation of gel surface coating erosion, and dissolution by a vaginal fluid simulant, and mathematical modeling of gel squeezing flow processes. Results suggest significant differences in extent of vaginal coating after gel application and in erosion of these gel layers due to contact with ambient vaginal fluid and shearing. The relationships between gel rheological properties, coating flow and erosion of coating were not always anticipated from differences in gel molecular composition.

[Toxicity of intravitreal injections of antibiotics and antivirals]

Intravitreal injections of antivirals, antifungals and antibiotics are very efficacious in the management of intraocular infections, which is not the case with per os, intravenous or peribulbar administration. However, these drugs have some toxic potential, more pronounced if used in intraocular condition. Being too toxic, aminoglycosides have been replaced by Ceftazidime and Vancomycine in the management of bacterial endophthalmitis. Efficacy of these drugs for prophylactic use is not demonstrated and their toxic potential remains to be kept in mind.

Can alcohol-based hand-rub solutions cause you to lose your driver's license? Comparative cutaneous absorption of various alcohols

We assessed cutaneous ethanol (ETOH) and isopropanol (ISOP) absorption after intensive (30 times per h) use of alcohol-based hand-rub solutions by healthcare workers (HCWs). ETOH was detectable in the breath of 6/20 HCWs (0.001 to 0.0025%) at 1 to 2 min postexposure and in the serum of 2/20 HCWs at 5 to 7 min postexposure. Serum ISOP levels were unrecordable at all time points.

Optimisation of polyherbal gels for vaginal drug delivery by Box-Behnken statistical design

The present research work aimed at development and optimisation of mucoadhesive polyherbal gels (MPG) for vaginal drug delivery. As the rheological and mucoadhesive properties of the gels correlate well to each other the prepared MPGs were optimised for maximum mucoadhesion using a relationship between the storage modulus (G') and Gel Index (GI), by employing a 3-factor, 3-level Box-Behnken statistical design. Independent variables studied were the polymer concentration (X(1)), honey concentration (X(2)) and aerosil concentration (X(3)). Aerosil has been investigated for the first time to improve the consistency of gels. The dependent variables studied were the elastic modulus, G'(Y(1)), gel index (Y(2)), and maximum detachment force (Y(3)) with applied constraints of 500<or=Y(1)<or=700 and 4<or=Y(2)<or=5. Response surface plots were drawn, statistical validity of the polynomials was established and optimised formulations was selected by feasibility and grid search. Three types of Carbopol studied were Carbopol 934P, Carbopol 974P and Polycarbophil. In vitro release studies were carried out for the optimised formulations and the data were fitted to release kinetics equations. Validation of the optimisation study with 8 confirmatory runs indicated high degree of prognostic ability of response surface methodology. Gels showed a gradual sustained release by a non-Fickian diffusion process. Incorporation of aerosil to gels was found to improve the rheological and mucoadhesion properties by about 50-54% and 7-11%, respectively. The Box-Behnken design facilitated the optimisation of polyherbal gel formulations for enhanced vaginal drug delivery by optimum mucoadhesion and longer retention.

Prospective study to determine the penetration of iodide into the anterior chamber following preoperative application of topical 1.25% povidone-iodine

BACKGROUND

Povidone-iodine is currently the agent of choice for pre-operative antisepsis in ophthalmology. Due to experimental and analytical constraints, iodine absorption into the anterior chamber (AC) has not yet been studied. However, knowledge of the details of iodine transfer into the aqueous humor (AH) is critical for risk assessment of local and/or systemic side effects

METHODS

Following a 2-min antisepsis with 1.25% povidone-iodine, the AC of eligible cataract patients was penetrated with a 26-gauge cannula prior to any other intraocular manipulation. To distinguish between the iodine absorbed into the AC and that remaining in the hypodermic delivery syringe, we studied three different groups of specimens: (i) AH from the AC (n=19); (ii) Ringer's solution aspirated through the cannula after penetration into and immediate withdrawal from the AC without subsequent decontamination (n=8); and (iii) Ringer's solution aspirated through the cannula after penetration into and immediate withdrawal from the AC, and subsequent decontamination of its outer surface (n=5). Patients with pre-operative epithelial defects were excluded from the study. To measure iodine absorption, iodide levels in samples were determined chromatographically (ion-pair chromatography) and electrochemically (gold electrode).

RESULTS

There was no difference (P=0.815) between detectable amounts of iodide in groups I and II (median: 24.0 microg/dl and 28.9 microg/dl, respectively). Only group III (median: 5.2 microg/dl) showed a statistically significant lower level of iodide than did groups I or II (P=0.019 and P=0.011, respectively).

CONCLUSIONS

A healthy ocular surface behaves as a barrier to the penetration of iodine into the AC. Any detectable iodide in the AH after antisepsis should therefore be considered harmless.

Pharmacokinetics of triclosan following oral ingestion in humans

The number of personal hygiene products containing triclosan has increased rapidly during the last decade, and triclosan is one of the most common antibacterial compounds used in dentifrices today. However, the extent of triclosan exposure has not yet been well described. The potential risks of generating triclosan-resistant pathogenic microorganisms or of the selection of resistant strains are some areas of concern. The aim of the present study was to (1) obtain information on baseline levels of triclosan in plasma and urine, and (2) study the pharmacokinetic pattern of triclosan after a single-dose intake. Ten healthy volunteers were exposed to a single oral dose of 4 mg triclosan by swallowing an oral mouthwash solution. Triclosan in plasma and urine was followed before and up to 8 d after exposure. Triclosan levels in plasma increased rapidly, with a maximum concentration within 1 to 3 h, and the terminal plasma half-life was 21 h. The major fraction was excreted within the first 24 h. The accumulated urinary excretion varied between the subjects, with 24 to 83% of the oral dose being excreted during the first 4 d after exposure. In conclusion, triclosan appears to be readily absorbed from the gastrointestinal tract and has a rapid turnover in humans. The high lipid solubility of the substance gives rise to questions regarding distribution properties and accumulation. The findings of the present study form a basis for greater understanding of the toxicokinetic properties of triclosan in humans.

Effect on infection resistance of a local antiseptic and antibiotic coating on osteosynthesis implants: an in vitro and in vivo study

The purpose of this study was to acquire information about the effect of an antibacterial and biodegradable poly-L-lactide (PLLA) coated titanium plate osteosynthesis on local infection resistance. For our in vitro and in vivo experiments, we used six-hole AO DC minifragment titanium plates. The implants were coated with biodegradable, semiamorphous PLLA (coating about 30 microm thick). This acted as a carrier substance to which either antibiotics or antiseptics were added. The antibiotic we applied was a combination of Rifampicin and fusidic acid; the antiseptic was a combination of Octenidin and Irgasan. This produced the following groups: Group I: six-hole AO DC minifragment titanium plate without PLLA; Group II: six-hole AO DC minifragment titanium plate with PLLA without antibiotics/antiseptics; Group III: six-hole AO DC minifragment titanium plate with PLLA + 3% Rifampicin and 7% fusidic acid; Group IV: six-hole AO DC minifragment titanium plate with PLLA + 2% Octenidin and 8% Irgasan. In vitro, we investigated the degradation and the release of the PLLA coating over a period of 6 weeks, the bactericidal efficacy of antibiotics/antiseptics after their release from the coating and the bacterial adhesion of Staphylococcus aureus to the implants. In vivo, we compared the infection rates in white New Zealand rabbits after titanium plate osteosynthesis of the tibia with or without antibacterial coating after local percutaneous bacterial inoculations at different concentrations (2 x 10(5)-2 x 10(8)): The plate, the contaminated soft tissues and the underlying bone were removed under sterile conditions after 28 days and quantitatively evaluated for bacterial growth. A stepwise experimental design with an "up-and-down" dosage technique was used to adjust the bacterial challenge in the area of the ID50 (50% infection dose). Statistical evaluation of the differences between the infection rates of both groups was performed using the two-sided Fisher exact test (p < 0.05). Over a period of 6 weeks, a continuous degradation of the PLLA coating of 13%, on average, was seen in vitro in 0.9% NaCl solution. The elution tests on titanium implants with antibiotic or antiseptic coatings produced average release values of 60% of the incorporated antibiotic or 62% of the incorporated antiseptic within the first 60 min. This was followed by a much slower, but nevertheless continuous, release of the incorporated antibiotic and antiseptic over days and weeks. At the end of the test period of 42 days, 20% of the incorporated antibiotic and 15% of the incorporated antiseptic had not yet been released from the coating. The antibacterial effect of the antibiotic/antiseptic is not lost by integrating it into the PLLA coating. The overall infection rate in the in vivo investigation was 50%. For Groups I and II the infection rate was both 83% (10 of 12 animals). In Groups III and IV with antibacterial coating, the infection rate was both 17% (2 of 12 animals). The ID50 in the antibacterial coated Groups III and IV was recorded as 1 x 10(8) CFU, whereas the ID50 values in the Groups I and II without antibacterial coating were a hundred times lower at 1 x 10(6) CFU, respectively. The difference between the groups with and without antibacterial coating was statistically significant (p = 0.033). Using an antibacterial biodegradable PLLA coating on titanium plates, a significant reduction of infection rate in an in vitro and in vivo investigation could be demonstrated. For the first time, to our knowledge, we were able to show, under standardized and reproducible conditions, that an antiseptic coating leads to the same reduction in infection rate as an antibiotic coating. Taking the problem of antibiotic-induced bacterial resistance into consideration, we thus regard the antiseptic coating, which shows the same level of effectiveness, as advantageous.

Pharmacokinetics of Chlorhexidine Gluconate 0.02% in the Rabbit Cornea

PURPOSE

The aim of this study was to determine the pharmacokinetic parameters of chlorhexidine gluconate (CHG) in the rabbit cornea.

METHODS

Each eye of 16 New Zealand white rabbits were topically instilled with 50 microL of CHG 0.02% eye drops twice with a 5-min interval. Four (4) corneas of 2 rabbits were harvested at each time point. The concentration of CHG in the cornea was determined with high-performance liquid chromatography (HPLC) and 387 software to simulate the pharmacokinetic parameters.

RESULTS

The concentration of CHG in the cornea displayed an open two-compartment model. Tmax was 13.75 min, Cmax 0.713 microg.g1, clearance rate 1.64 microg.g-1.min-1, and t1/2alpha, t1/2beta, and t1/2ka was 2.65, 48.72, and 2.67 min, respectively.

CONCLUSIONS

The concentration of CHG in the rabbit cornea could be determined by means of HPLC. The maximum concentration of CHG in the corneal tissue was much higher than the trophozoite minimum amoebicidal concentration (TMAC) in vitro.

Adsorption of chlorhexidine and black tea onto in vitro salivary pellicles, as studied by ellipsometry

The adsorption from 0.2% (w/w) chlorhexidine and black tea solutions onto an in vitro pellicle from whole unstimulated saliva on hydroxyapatite discs was studied by ellipsometry. It was found that chlorhexidine adsorbed to the pellicle and caused a modification of the pellicle properties, leading to a subsequent increase in adsorption of salivary and black tea components. There was a distinct order-of-addition effect, whereby chlorhexidine followed by black tea gave an overall greater adsorption of components compared with black tea followed by chlorhexidine. This increase in adsorption resulted in a concomitant increase in color or stain, as measured by a reflectance chromameter. The increase in adsorbed amounts and stain was modified, in part, by the adsorption of salivary fractions between the chlorhexidine and black tea treatments. In all cases, the chlorhexidine and black tea-modified pellicles were not readily removed by either phosphate or sodium dodecyl sulfate rinses. Thus, following exposure to chlorhexidine, the accelerated adsorption of salivary and black tea components can ultimately lead to increased staining of the pellicle.

Systemic Iodine Absorption after Preoperative Antisepsis Using Povidone-Iodine in Cataract Surgery – An Open Controlled Study

After preoperative conjunctival and periorbital antisepsis with povidone-iodine (PVP-I), the systemic absorption of iodine after cataract surgery was measured to evaluate the risk of thyroid side effects. Five different combinations of PVP-I alone or in combination with PVP-I-free antiseptics were applied to the conjunctiva and periorbital skin. An iodine-free product served as control. Iodide and creatinine in urine were analyzed before intervention and 24 and 48 h postoperatively. Depending on the concentration and application site, 0.3-4.5% of the total applied iodine or 3.6-45.4% of the free iodine were absorbed. The range of urine iodine excretion was between 11.7 and 71.0 mug iodine/g creatinine, depending on the PVP-I concentration and the site of application. The increase in iodine excretion was significant at 24 h postoperatively in trials receiving PVP-I both periorbitally and conjunctivally, depending of the concentration used. Because the iodine absorption is only slight and of doubtful clinical relevance, presurgical conjunctival antisepsis can be achieved with 1.25% PVP-I; so far clinically manifest anamnestic thyroid disorders are excluded. Presently, periorbital skin antisepsis with PVP-I cannot be recommended until data on thyroid metabolism in the population have been collected and evaluated, especially in a region currently or previously deficient in iodine.

Position Paper: The Role of Supra- and Subgingival Irrigation in the Treatment of Periodontal Diseases

This position paper addresses the role of supra- and subgingival irrigation in the treatment of periodontal diseases. It was prepared by the Committee on Research, Science and Therapy of the American Academy of Periodontology. The document is divided into two portions, consisting of supragingival irrigation and subgingival irrigation. In their respective segments, these treatment techniques are assessed as monotherapies and as adjuncts to conventional treatment. The conclusions drawn in this paper represent the position of the American Academy of Periodontology regarding irrigation therapy in the treatment of periodontal diseases.

Comparison of Silver-Coated Dressing (Acticoat???), Chlorhexidine Acetate 0.5% (Bactigrass??), and Silver Sulfadiazine 1% (Silverdin??) for Topical Antibacterial Effect in Pseudomonas Aeruginosa-Contaminated, Full-Skin Thickness Burn Wounds in Rats

Acticoat (Smith and Nephew, Istanbul, Turkey), chlorhexidine acetate 0.5%, and silver sulfadiazine 1% were compared to assess the antibacterial effect of their application on experimental burn wounds in contaminated with Pseudomonas aeruginosa in rats. All treatment modalities were effective against P. aeruginosa because there were significant differences between treatment groups and control groups. The mean eschar concentrations did not differ significantly between Acticoat and chlorhexidine acetate groups, but there were significant differences between the silver sulfadiazine group and the other treatment groups, indicating that silver sulfadiazine significantly eliminated P. aeruginosa more effectively in the tissues than did the other two agents. All treatment modalities were sufficient to prevent the P. aeruginosa from invading to the muscle and from causing systemic infection. In conclusion, silver sulfadiazine is the most effective agent in the treatment of the P. aeruginosa-contaminated burn wounds; Acticoat can be considered as a treatment choice because of its peculiar ability of limiting the frequency of replacing wound dressings.

Efficacy of a high bioavailable cetylpyridinium chloride mouthrinse over a 24-hour period: a plaque imaging study

PURPOSE

To evaluate the antiplaque benefits of a 0.07% high bioavailable, alcohol-free cetylpyridium chloride (CPC) rinse used after toothbrushing versus toothbrushing alone.

METHODS

A digital plaque image analysis technique was used to quantify in situ plaque formation in a subject population carrying out modified hygiene using standard fluoridated dentifrice or standard dentifrice augmented with 30 seconds mouthrinsing with an alcohol-free mouthrinse containing 700 ppm CPC.

RESULTS

Comparison of plaque formation 24 hours following "last hygiene" revealed that brushing followed by CPC mouthrinse use provided a statistically significant decrease in plaque coverage on teeth averaging 42% as compared with brushing only. Moreover, toothbrushing with a standard dentifrice in the morning resulted in 34% less plaque when subjects used the CPC mouthrinse 24 hours prior to examination.

CLINICAL SIGNIFICANCE

These results support the strong retention and lasting antiplaque efficacy of high bioavailable CPC mouthrinse and suggest that the plaque biofilms formed during CPC use are susceptible to more efficient debridement.

Transcutaneous iodine absorption in adult patients with thyroid cancer disinfected with povidone-iodine at operation

Povidone-iodine is used as disinfection in patients undergoing many kinds of operations. Several cases of thyroid dysfunction induced by transcutaneous absorption of povidone-iodine have been reported in small infants. However, transcutaneous absorption was not clearly reported in adults. The aim of this study was to assess transcutaneous absorption of iodine in patients who received single topical application with povidoneiodine and serial changes of urinary iodine excretion under the condition with a simple iodine-restricted diet in Japan, an iodine-sufficient area. Sixty-eight patients with thyroid carcinoma undergoing total thyroidectomy received single skin disinfection with either povidone-iodine (group A; n = 47) or chlohexidine gluconate, a noniodine containing biguanide (group B; n = 21). In group A, urinary iodine excretion on the first day after operation increased up to 7 times that of the preoperative value. The amounts of urinary iodine correlated positively with operating time. Increased urinary iodine, however, returned to preoperative values on the third or fifth day after operation. In group B, there was no increase in urinary iodine excretion and urinary iodine excretion was ranged from 54 to 193 microg/g of creatinine on the third day of operation. In conclusion, a large amount of povidone-iodine was absorbed through healthy skin even in adults. This may possibly interfere with scintigraphy or radioactive iodine treatment, or cause thyroid disinfection in susceptible patients.

Increase in activity of essential oil components carvacrol and thymol against Escherichia coli O157:H7 by addition of food stabilizers

The major components of oregano and thyme essential oils that had previously been shown to inhibit Escherichia coli O157:H7 were determined by high-performance liquid chromatography with UV detection and liquid chromatographic tandem mass spectrometry. The MICs and MBCs of carvacrol, thymol, p-cymene, and gamma-terpinene against a strain of E. coli O157: H7 phage type 34 isolated from bovine feces were determined by microdilution assay. The constituents were then tested in checkerboard assays to detect possible interactions. Carvacrol and thymol displayed bacteriostatic and bactericidal properties with MICs of 1.2 mmol/liter and were additive in combination. p-Cymene and gamma-terpinene displayed no measurable antibacterial activity up to 50 mmol/liter, and neither influenced the activity of carvacrol or thymol. Growth curves in the presence of nonlethal concentrations of carvacrol with the addition of agar (0.05%, wt/vol) or carrageenan (0.125%, wt/vol) as stabilizer were produced by optical density measurement. The stabilizers agar and carrageenan both significantly improved the effectiveness of carvacrol in broth, possibly because of a delay in the separation of the hydrophobic substrate from the aqueous phase of the medium. When carvacrol was dissolved in ethanol before addition to broth, stabilizers were not needed. Carvacrol and thymol, particularly when used in combination with a stabilizer or in an ethanol solution, may be effective in reducing the number or preventing growth of E. coli O157:H7 in liquid foods.

Residues of spinosad in the tissues of sheep after aerosol treatment of blowfly myiasis

OBJECTIVE

To measure the residues of spinosad and chlorhexidine in the tissues of sheep after treatment of blowfly strike.

PROCEDURE

Fourteen sheep with natural myiasis and 12 with artificial infestations of Lucilia cuprina larvae had the wool removed over their infestations and were treated with an aerosol wound dressing containing spinosad and chlorhexidine. Sheep were killed up to 14 days after treatment and residues of the chemicals measured in tissues.

RESULTS

Chlorhexidine was not detected in any tissue. Residues of spinosad were highest in fat, lowest in muscle and intermediate in liver and kidney. The highest residue detected was 0.2 mg/kg spinosad in perirenal fat 7 days after generous treatment of a sheep with a large fly strike. Residues of spinosad in fat peaked 3 to 7 days after treatment and 1 to 3 days after treatment in liver and kidney.

CONCLUSION

These studies present a realistic worst-case in struck sheep and at the highest dose studied, equivalent to 5.8 mg spinosad per kg body weight, the maximum residue detected of 0.2 mg/kg in peri-renal fat was 20% of the Australian maximum residue limit. Muscle, liver and kidney residues of spinosad were also below the Australian maximum residue limits at all times.

Co-occurrence of triclocarban and triclosan in U.S. water resources

Triclocarban (TCC) and triclosan (TCS) are antimicrobial additives in personal care products. Whereas TCS has been studied extensively, the environmental fate of TCC remains largely unknown. To address this data gap, we performed quantitative structure-activity relationship (QSAR) analyses that suggested a propensity of TCC to persist in various environmental compartments with predicted half-lives ranging from 0.75 days in air to 540 days in sediment. Moreover, concentrations of both antimicrobials were measured in 42 environmental samples from the Greater Baltimore region using a combination of solid-phase extraction, liquid chromatography/mass spectrometry, and isotope dilution. The co-occurrence of TCC and TCS was observed, owing to similar properties, usage, disposal, and environmental half-lives. A linear empirical correlation (R2 = 0.9882) fit the log-log-transformed data from diverse aquatic media and spanned 5 orders of magnitude in concentration. Occurrences of TCC predicted for 85 U.S. streams were statistically indistinguishable from experimental regional data (alpha < or = 0.05). Annual loading of antimicrobials to water resources probably is dominated by activated sludge treatment plants (39-67%), followed by trickling filters (31-54%) and combined and sanitary sewer overflows (2-7% and <0.2%, respectively). Study results suggest that TCC is a previously unrecognized contaminant of U.S. water resources nationwide, likely ranking in the top 10 in occurrence rate and in the top 20 in maximum concentration among 96 organic pollutants considered. The magnitude and frequency of TCC contamination (regional, 6750 ng/L, 68%; predicted nationwide for 1999--2000, 1150 ng/L, 60%) were markedly higher than non-peer-reviewed numbers (240 ng/L, 30%, U.S.) currently used by the U.S. Environmental Protection Agency for evaluating TCC's ecological and human health risks.

Intravaginal gels as drug delivery systems

Recently, there has been a great deal of interest in the design and application of different dosage forms via the vaginal route. Several studies have proven that the vagina is an effective route for drug administration intended mainly for local action, but systemic effects of some drugs also can be attained. The major advantages of this route include accessibility, good blood supply, the ability to bypass first-pass liver metabolism, and permeability to large molecular weight drugs, such as peptides and proteins. Among the delivery systems proposed for this route is the use of intravaginal gels, which have been found to be potential vaginal drug delivery systems. The bioadhesives used in the formulation of gels play a key role in the release of the drug through the attachment to the vaginal mucosa, where the drug diffuses from the gel to the mucus.

Decrease in Skin Permeation and Antibacterial Effect of Parabens by a Polymeric Additive, Poly(2-methacryloyloxyethyl phosphorylcholine-co-butylmetacrylate)

The inhibitory effect of poly(2-methacryloyloxyethyl phosphorylcholine-co-butylmetacrylate) (PMB) on the in vitro skin permeation of p-hydroxybenzoic acid and its esters (parabens; methylparaben, ethylparaben, n-propylparaben and n-butylparaben) as model compounds was evaluated. Solubility of the parabens in distilled water was increased by addition of PMB, and the increasing ratio was dependent on the concentration of PMB. The increment of the ratio was more marked in lipophilic parabens than hydrophilic ones. Skin permeability of parabens from their aqueous suspensions was decreased by addition of PMB, and the decreasing ratio was dependent on the PMB concentration. Then, antibacterial effect of parabens of their aqueous solutions was determined with and without PMB by measuring minimum inhibitory concentration (MIC) against E. coli and S. aureus. As results, MIC and antibacterial effect were increased and decreased, respectively, by addition of PMB. The contribution of PMB was more marked in butylparaben than methylparaben. These decreases in skin permeation and antibacterial effect of parabens by PMB are probably due to a higher solubility in water and a lower partition to the skin and bacterial membranes of parabens by addition of PMB.

Incorporation of low molecular weight biocides into polystyrene–divinyl benzene beads with controlled release characteristics

Triclosan and phosphonium salt biocides have been separately incorporated into polystyrene-divinylbenzene (PS-DVB) beads by suspension polymerization. Ultraviolet (UV) absorption measurements have been used to monitor the release of these low molecular weight biocides out of the PS-DVB beads immersed in water-ethanol mixtures and in physiological saline. The release of the biocide agents is strongly dependent on either the DVB or/and the antimicrobial composition ratio in the beads. An increase of biocide incorporation in the PS/DVB beads was accompanied by a corresponding enhancement of its concentration in liquid mixtures. On the contrary, higher cross-linking densities hindered the biocide migration out of the beads by diminishing its release rate into either the aqueous ethanol solutions or the natural serum. Moreover, Fourier transform Raman (FT-Raman) spectra and Attenuated Total Reflectance Infrared (ATR-FTIR) measurements of the PS-DVB-Triclosan and PS-DVB-phosphonium salt beads, before and after their immersion in water-ethanol solutions, gave a similar qualitative evidence of the biocide release.

Liposomal gel with chloramphenicol: characterisation and in vitro release

The aim of our study was to develop a liposomal carrier system for the local treatment of bacterial vaginosis, capable to efficiently deliver entrapped drug during an extended period of time. Chloramphenicol was entrapped in liposomes composed of egg phosphatidylcholine/egg phosphatidylgycerol-sodium (9:1, molar ratio) and prepared by two different methods, the proliposome method and the polyol dilution method. Both liposome preparations were characterised and compared for particle size, polydispersity, entrapment efficiency and tested for in vitro stability in media that simulate human vaginal conditions (buffer pH 4.5 and vaginal fluid simulant). To achieve application viscosity of liposomes and to further improve their stability, liposomes prepared by the proliposome method were incorporated in the bioadhesive gel made of Carbopol 974P NF resin. In vitro release studies of liposomes incorporated in the gel have shown a prolonged release of entrapped chloramphenicol compared to control gel. Even after 24 hours of incubation in the vaginal fluid simulant, more than 40% of the originally entrapped drug was still retained in the gel. Storage stability studies have proven the ability of the Carbopol 974P NF gel to preserve the original size distribution of incorporated liposomes. All the performed experiments confirm the applicability of liposomes as a novel drug carrier system for the local treatment of bacterial vaginosis.

Release of antiseptics from the aqueous compartments of a w/o/w multiple emulsion

A w/o/w multiple emulsion drug carrier system has been developed for local vaginal therapy. To improve its efficacy and to extend the antimicrobial spectrum activity of benzalkonium chloride (CBZ), which is introduced in the external aqueous phase, chlorhexidine digluconate (CHD) was added to the internal aqueous phase of the multiple emulsions. The minimal bactericidal concentrations (MBC) for the association of CHD and CBZ in emulsion were determined towards Escherichia coli and Staphylococcus aureus. The main release mechanism considered for the CHD encapsulated in the inner phase was a swelling-breakdown phenomenon which followed dilution of the emulsion under hypo-osmotic conditions. In order to demonstrate this release, the bactericidal effect of multiple emulsions undiluted and diluted 1-5 and 1-10 in hypo-osmotic conditions at two CHD concentrations was evaluated. To validate and quantify this release, rheological and release kinetics studies were used. The bactericidal activity of combination CBZ-CHD in the emulsion was synergistic on the two bacterial strains and the release of encapsulated CHD in the internal phase was obtained following its dilution in hypo-osmotic conditions. Vaginal administration could be carried out following dilution at 1-5 in sterile water for multiple emulsions containing the lower concentration of CHD.