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PubMed1995

Primary interactions of three quaternary ammonium compounds with blastospores of Candida albicans (MEN strain).

The absorption of three quaternary ammonium compounds (QAC), cetylpyridinium chloride, cetrimide and benzalkonium chloride, onto the surface of blastospores of Candida albicans (MEN strain) was examined at room temperature. Equilibrium uptake occurred in less than 30 seconds for cetylpyridinium chloride and cetrimide whereas 5 min contact time was required for benzalkonium chloride. The adsorption of all three agents may be mathematically described as Langmuirian and hence a concentration-dependent formation of drug-monolayer on the surface of the blastospore occurred. From this the number of molecules adsorbed onto the surface of a single blastospore was calculated to be 1.33 x 10(12), 3.17 x 10(12) and 2.32 x 10(12) for cetylpyridinium chloride, cetrimide and benzalkonium chloride, respectively. These dissimilarities are most likely due to differences in the orientations of both the cationic nitrogen atom and the accompanying lipophilic portions of each QAC at the blastospore surface. Relating these observations to the known antiadherence effects of cetylpyridinium chloride and cetrimide, it can be concluded that monolayer coverage of the blastospore surface with QAC does not account for the observed reduced adherence. This suggests that the anti-adherence effects are due to either direct interaction with, or steric blockade of, adhesions on the blastospore surface.

Adsorption↗
PubMed2003

Separation of aliphatic and aromatic acids, aromatic sulfonates, quaternary ammonium compounds, and chelating agents on a reversed-phase column without ion pairing.

Cleaning products contain a wide variety of components. These include inorganic materials, weak acids, anionic surfactants, cationic surfactants, amphoteric compounds, and nonionic materials. The separation of these generally requires the use of multichromatographic modes. A system is developed that would give the maximum information for a cleaning product in a single chromatographic run. With the use of a hydrophobic, high-carbon-loading, and a relatively hydrophobic surface reversed-phase packing, such compounds as aromatic sulfonates, quaternary ammonium compounds, weak acids, nitrilotriacetic acid, ethylenediaminetetraacetic acid, and nonionic materials may be separated in a single run. The mode of separation is considered to be a combination of reversed-phase, ion-suppression reversed-phase, and adsorption chromatography. The separation is made on a YMC-Packl ODS-AQl column (4.6 x 250 mm, 120 angstroms). The separation employs a gradient run starting with 0.01 N H2SO4 for 10 min followed by a gradient for 15 min to 100% acetonitrile and continuing for an additional 5 min with 100% acetonitrile. The flow rate is 1 mL/min, and the separation is monitored at 210 nm.

Journal Article↗
PubMed2006

Determination of selected quaternary ammonium compounds by liquid chromatography with mass spectrometry. Part II. Application to sediment and sludge samples in Austria.

Soxhlet extraction and high-performance liquid chromatography (HPLC) coupled to tandem mass spectrometry detection (MS/MS) was used for the determination of selected quaternary ammonium compounds (QACs) in solid samples. The method was applied for the determination of alkyl benzyl, dialkyl and trialkyl quaternary ammonium compounds in sediment and sludge samples in Austria. The overall method quantification limits range from 0.6 to 3 microg/kg for sediments and from 2 to 5 microg/kg for sewage sludges. Mean recoveries between 67% and 95% are achieved. In general sediments were especially contaminated by C12 chain benzalkonium chloride (BAC-C12) as well as by the long C-chain dialkyldimethylammonium chloride (DDAC-C18) with a maximum concentration of 3.6 mg/kg and 2.1mg/kg, respectively. Maxima of 27 mg/kg for DDAC-C10, 25 mg/kg for BAC-C12 and 23 mg/kg for BAC-C14 were determined for sludge samples. The sums of the 12 selected target compounds range from 22 mg/kg to 103 mg/kg in the sludge samples.

Austria↗
PubMed1971

Resistance of Pseudomonas to quaternary ammonium compounds. II. Cross-resistance characteristics of a mutant of Pseudomonas aeruginosa.

Tube dilution experiments showed that benzalkonium chloride (BC)-resistant mutants of Pseudomonas aeruginosa grown in the presence of 1,000 mug of BC per ml were at least 20 times more sensitive to polymyxin B and colistin sulfate than the BC-sensitive (BCS) parent strain. BCS cells selected for resistance to 500 mug of polymyxin B per ml remained sensitive to BC. There was little difference in the amount of carbenicillin, gentamicin sulfate, or rifampin needed to prevent growth of either the BCS or BC-resistant (BCR) strains. Growth of BCR cells was inhibited by ethylenediaminetetraacetate at a concentration of 400 mug/ml or less, whereas the BCS strain grew at ethylenediaminetetraacetate levels of 10,000 mug/ml. Phenylmercuric acetate and thimerosal inhibited growth of BCR and BCS cells at concentrations of 10 mug/ml or less. BCR cells were cross-resistant to >1,000 mug/ml concentrations of five other quaternary ammonium compounds, including three with C(16) alkyls and two with alkyl groups of shorter length. The BCS strain was also resistant to >1,000 mug/ml concentrations of the three quaternary ammonium compounds with C(16) alkyl groups but, in addition to BC, was inhibited by 200 mug/ml levels or less of the two quaternary ammonium compounds containing alkyl groups of less than 16 carbon atoms.

Anti-Bacterial Agents↗
PubMed1999

Loss of bactericidal capacity of long-chain quaternary ammonium compounds with protein at lowered temperature.

Amphiphilic betaine esters are quaternary ammonium compounds (QACs) with rapid microbicidal effect, which spontaneously hydrolyze into nontoxic products. thus being referred to as soft antimicrobial agents. The bactericidal effect of 1-decyl (B10), 1-dodecyl (B12), and 1-tetradecyl (B14) betaine esters on Salmonella typhimurium was strongly influenced by temperature, pH and length of hydrocarbon chain. At pH 6.0, presence of 1.5 mM (10% w/v) BSA raised the concentration of B14 for 99% killing (BC2) from 0.006 mM to 1.8 mM. There was a stoichiometric relationship between concentration of BSA and BC2 of B14, indicating that one molecule of B14 was bound per BSA molecule when 99% killing was achieved. When the temperature was lowered to 0 degrees C only minor killing was seen in 1.5 mM BSA at the highest concentration of B14 tested, 57 mM. With B10 at 30 degrees C and pH 6.0, the presence of 1.5 mM BSA raised the bactericidal concentration (BC2) from 0.69 mM to 4.1 mM, and at 0 degrees C and 1.5 mM BSA the BC2 was 11 mM. Thus, the impairment caused of the bactericidal effect of B10 by BSA and lower temperature was less than for B14, since B14 is much more active than B10 at 30 degrees C in the absence of BSA, somewhat more active than B10 at 30 degrees C in the presence of 1.5 mM BSA, and much less active than B10 at 0 degrees C in the presence of BSA. B12 showed properties intermediate between B10 and B14. Lowered pH reduced the bactericidal effect particularly when reduced from pH 5.0 to 4.0 with B10. In the presence of 1.5 mM BSA, the bactericidal effect of 1-dodecyl (DTAB) and 1-hexadecyl (CTAB) trimethylammonium bromide decreased in the same manner as for B10 and B14, respectively. Increasing the time of incubation at 0 degrees C to 50 min, a 99% killing effect was seen with 17 mM CTAB, whereas the same killing effect was reached in 8 min with 17 mM DTAB. Binding of [3H]CTAB to S. typhimurium was also reduced at 0 degrees C in the presence of BSA. Thus, in the presence of 1.5 mM BSA, QACs with the longer hydrocarbon chain were most efficient at 30 degrees C, whereas at 0 degrees C those with the shorter hydrocarbon chain were most active. Consequently, QACs with shorter tails should be used for disinfection in the presence of proteins at lower temperatures.

Cetrimonium↗
PubMed1979

The feasibility of replacing antibiotics by quaternary ammonium compounds in topical antimicrobial acne therapy.

Determinations of the minimum inhibitory concentrations for various antimicrobial surfactants with reference to the bacteria P. acnes, P. granulosum, and St. epidermidis are reported. The results show that quaternary ammonium compounds can display minimum inhibitory concentrations corresponding to those of relevant antibiotics. With the especially effective substance fractionated dimethylcocobenzalkoniumchloride )ARQUAD DMMCD-B), it could be further shown that with in vivo application in 70% isopropanol or in an ethanol-containing film mask ointment suppression can be obtained of P. acnes, all propionibacteria added, and all pilosebaceous duct bacteria which can be cultured under anaerobic conditions. The studies may point out a way of replacing antibiotics in the antimicrobial therapy of acne by quaternary ammonium compounds.

Acne Vulgaris↗
PubMedDate not supplied

Virucidal efficacy of the newer quaternary ammonium compounds.

The virucidal activity of several disinfectants containing newer generation quaternary ammonium compounds (QACs) as their active ingredients was evaluated. Disinfectants were used at the manufacturers' recommended dilutions with isolates of feline herpesvirus, feline calicivirus, and canine parvovirus, and a contact time of 10 minutes at room temperature. Detoxification of virus/disinfectant solutions was done by dialysis prior to virus assay in cell cultures. Two of four disinfectants completely inactivated feline herpesvirus, and two significantly reduced the titer of this virus. None of the disinfectants that were tested completely inactivated feline calicivirus. Canine parvovirus was not inactivated significantly by any of the QAC disinfectants. Sodium hypochlorite completely inactivated all viruses.

Animals↗
PubMed1986

Induction of contact dermatitis in guinea pigs by quaternary ammonium compounds: the mechanism of antigen formation.

Eight quaternary ammonium compounds were tested for their ability to induce contact dermatitis in guinea pigs by using a modified Freund's complete adjuvant test together with the guinea pig maximization test. Only two quaternary ammonium salts of the eight tested could be designated as strong allergens. These two active substances were shown to be capable of stable association with membrane lipids in forming immunogenic complexes. This surface complexation phenomenon was confirmed by using a spin-labeled quaternary ammonium salt which competed for binding sites at the surface of epidermal cells in vivo. Electron spin resonance was used to demonstrate that stable "ion-pairs" are formed between binding sites and the two allergenic preservatives. Furthermore, information was obtained on the kinetics of immunogenic complex formation as well as on the position and orientation of the quaternary ammonium ion at the cell surface.

Allergens↗
PubMed1982

Enhanced entrapment of a quaternary ammonium compound in liposomes by ion-pairing.

The encapsulation of a quaternary ammonium compound by multilamellar liposomes was enhanced by formation of ion-pairs with a counterion. Thus, [14C]methantheline bromide was synthesized and paired with a 25 M excess of trichloroacetate. Under these conditions, the amount of radioactivity entrapped by phosphatidylcholine liposomes was three times greater than when no trichloroacetate was present. The increased liposomal loading was probably due to the solubilization of the ion-pair in the lipid membrane of the liposome.

Chemical Phenomena↗
PubMed2006

In vitro antiseptic properties of an ammonium compound combined with denture base acrylic resin.

BACKGROUND: Denture base acrylic resin is easily colonised by oral endogenous bacteria and Candida spp., and eventually by extra-oral species such as Staphylococcus spp., Pseudomonadaceae or members of Enterobacteriaceae. This microbial reservoir can be responsive for denture related stomatitis and aspiration pneumonia, a life-threatening infection especially in geriatric patients. However, the oral and denture hygiene of dependent elderly individuals is extremely poor. OBJECTIVE: This in vitro study aimed to determine the per cent of a quaternary ammonium compound heat-polymerised in acrylic resin necessary to obtain denture base displaying antiseptic properties. DESIGN: Acrylic resin discs containing 2-50% ammonium polymer (Poly 202063A; 0% control) were soaked in artificial saliva for 4 weeks. Resin discs were incubated for 24 hours with Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa [37 degrees C, brain-heart infusion (BHI) broth and phosphate-buffered saline (PBS) buffer] and Candida albicans (30 degrees C, Schaedler broth), in 15 ml (168 discs) and 600 microl (168 discs) of inoculum. Microbial growth was verified at t 0 hours and t 24 hours. Data were recorded as the mean of three colony forming unit (CFU) numerations. The borderline of antimicrobial effect was determined at 0.1% viable cells. RESULTS: In 600 microl of PBS inoculum, resin specimens had a bactericidal effect (E. coli and S. aureus: 2%; P. aeruginosa: 10%) and a fungicidal effect (C. albicans: 50%). Long-term stability and toxicity in vivo studies are now required. CONCLUSION: A 2% quaternary ammonium compound polymerised with a denture acrylic resin displayed antiseptic properties after a 4-week soaking period in artificial saliva. Such antiseptic denture base could help geriatric patients to improve their oral health.

Acrylic Resins↗
PubMed1994

Mechanism of long-lasting block of ganglion nicotinic receptors by mono-ammonium compounds with long aliphatic chain.

The effect of long-chain mono-ammonium compounds (long-chain MACs), t-butyldecylammonium (IEM-1078), 2,2,6,6-tetramethyldecylpiperidine (IEM-1559), and diisopropyldecylammonium (IEM-1194), on nicotinic acetylcholine receptors (nAChRs) was studied in sympathetic ganglion neurons using the patch clamp method. Long-chain MACs (1-10 microM) strongly inhibited acetylcholine (ACh)-induced current (ACh-current); the block persisted for hours after washing the drugs out. Short-chain MACs had a much weaker and completely reversible blocking effect. Suppression of ACh-current by MACs was dose- and voltage-dependent; it was absent at low ACh doses or at potentials > or = 60 mV and increased with higher ACh doses or hyperpolarization. The second of two ACh-currents induced by paired application of ACh was inhibited by long-chain MACs more strongly than the first. This use-dependent block also persisted for hours after washing the drugs out. Additional inhibition of the second ACh-current was reduced by lengthening the time interval between ACh applications in the pair. Time constants of the recovery of the second ACh-current in the presence and after washing out of long-chain MACs were similar, ranging from 45 to 140 s at -50 mV for different long-chain MACs, and decreased with de- or hyperpolarization. The use-dependent block produced by long-chain MACs could be prevented by another long-chain MAC with a small ammonium head (IEM-1195, 75-100 microM) or trimethaphan (30 microM), a competitive antagonist of ACh in ganglia. Neither the short-chain MAC (IEM-1405, 100 microM) nor ACh (100 microM) could exert this protective effect. Long-chain MACs did not exert any use-, dose- or voltage-dependent suppression of ACh-current when applied intracellularly. Single-channel conductance was not affected by IEM-1194 (3-10 microM). We suggest that inhibition of ACh-current by long-chain MACs is accounted for by (i) a long-lasting, apparently irreversible, binding of the drug near the channel of nAChR via its long aliphatic chain and (ii) a slow reversible block of the nAChR channel with the MAC's ammonium head.

Acetylcholine↗
PubMed1992

Evaluation of antimicrobial interactions between chlorhexidine, quaternary ammonium compounds, preservatives and excipients.

The antimicrobial interactions of 49 combinations of chlorhexidine, quaternary ammonium compounds, preservatives and excipients were evaluated by the method of Berenbaum and the checkerboard titration method, with Staphylococcus aureus CIP 53154 and Escherichia coli CIP 54127 as test strains. MIC determinations were carried out as a preliminary step, and relative growth intensity was used to describe the bacteriostatic activity of surface-active agents (Amonyl 380 BA, Amonyl 671 SB). In the study of combinations, results were interpreted with Fractional Inhibitory Concentration indexes and represented by isobolograms. A fair correlation was shown between the method of Berenbaum and the checkerboard titration method. Combinations between chlorhexidine, cetrimonium bromide and benzalkonium chloride were synergistic or additive; combinations of antiseptics and preservatives were generally not antagonistic. The methods were also well adapted to the study of interactions involving surface-active agents, a critical problem in the formulation of topical antimicrobial agents.

Anti-Infective Agents, Local↗