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PubMed1983

Bilirubin-displacing effect of ampicillin, indomethacin, chlorpromazine, gentamicin, and parabens in vitro and in newborn infants.

Displacement of bilirubin bound to human serum albumin by ampicillin, indomethacin, chlorpromazine, gentamicin, methylparaben, and propylparaben was investigated quantitatively. Two methods were used in vitro: measurement of bilirubin displacement by studying the rate of bilirubin oxidation with hydrogen peroxide and peroxidase and determination of the albumin reserve for binding of bilirubin by observation of the dialysis rate of an added trace amount of a deputy ligand monoacetyldapsone (p-acetamido-p'-aminodiphenyl sulfone). The latter method was also used for the determination of the albumin reserve in sera from treated newborn infants. The following doses were given: ampicillin, 100 mg/kg iv; indomethacin, 0.2 mg/kg iv; chlorpromazine hydrochloride, 0.7 mg/kg im; gentamicin sulfate, 2.5 mg/kg im. The parabens were present in injectable preparations of chlorpromazine and gentamicin and were therefore given in the following doses: methylparaben, 0.35 mg/kg, and propylparaben, 0.05 mg/kg. All drugs were given in a single dose. A few additional additives and metabolites were studied in vitro. Ampicillin, given to 19 infants, produced a small, significant decrease in plasma albumin reserve, to 82% of the pretreatment level and, thus, had a slight bilirubin-displacing effect, quantitatively consistent with a weak displacing effect measured in vitro. None of the other substances showed any measurable displacement in vivo, likewise in agreement with the results from in vitro studies.

Ampicillin↗
PubMed2004

Simultaneous HPLC determination of ketoprofen and its degradation products in the presence of preservatives in pharmaceuticals.

A novel and quick high-performance liquid chromatography (HPLC) method with UV spectrophotometric detection was developed and validated for the determination of five compounds in topical gel. The described method is suitable for simultaneous determination of active component ketoprofen, two preservatives methylparaben and propylparaben and two degradation products of ketoprofen--3-acetylbenzophenone and 2-(3-carboxyphenyl) propionic acid--in a topical cream after long-term stability tests using ethylparaben as an internal standard. The chromatographic separation was performed on a 5microm Supelco Discovery C18 column (125mm x 4mm i.d., Sigma-Aldrich); the optimal mobile phase for separation of ketoprofen, methylparaben, propylparaben, degradation products 3-acetylbenzophenone and 2-(3-carboxyphenyl) propionic acid and ethylparaben as internal standard consists of a mixture of acetonitril, water and phosphate buffer pH 3.5 (40:58:2, v/v/v). At a flow rate of 1.0ml min(-1) and detection at 233nm, the total time of analysis was less than 10min. The method was applied for routine analysis (batch analysis and stability tests) of these compounds in topical pharmaceutical product.

Chromatography, High Pressure Liquid↗
PubMed2006

Development and validation of chemometrics-assisted spectrophotometric and liquid chromatographic methods for the simultaneous determination of two multicomponent mixtures containing bronchodilator drugs.

Three methods are developed for the determination of two multicomponent mixtures containing guaiphenesine (GU) with salbutamol sulfate (SL), methylparaben (MP) and propylparaben (PP) [mixture 1]; and acephylline piperazine (AC) with bromhexine hydrochloride (BX), methylparaben (MP) and propylparaben (PP) [mixture 2]. The resolution of the two multicomponent mixtures has been accomplished by using numerical spectrophotometric methods such as partial least squares (PLS-1) and principal component regression (PCR) applied to UV absorption spectra of the two mixtures. In addition HPLC method was developed using a RP 18 column at ambient temperature with mobile phase consisting of acetonitrile-0.05 M potassium dihydrogen phosphate, pH 4.3 (60:40, v/v), with UV detection at 243 nm for mixture 1, and mobile phase consisting of acetonitrile-0.05 M potassium dihydrogen phosphate, pH 3 (50:50, v/v), with UV detection at 245 nm for mixture 2. The methods were validated in terms of accuracy, specificity, precision and linearity in the range of 20-60 microg ml(-1) for GU, 1-3 microg ml(-1) for SL, 20-80 microg ml(-1) for AC, 0.2-1.8 microgml(-1) for PP and 1-5 microg ml(-1) for BX and MP. The proposed methods were successfully applied for the determination of the two multicomponent combinations in laboratory prepared mixtures and commercial syrups.

Albuterol↗
PubMed2002

Oestrogenic activity of parabens in MCF7 human breast cancer cells.

Parabens (4-hydroxybenzoic acid esters) have been recently reported to have oestrogenic activity in yeast cells and animal models. Since the human population is exposed to parabens through their widespread use as preservatives in foods, pharmaceuticals and cosmetics, we have investigated here whether oestrogenic activity of these compounds can also be detected in oestrogen-sensitive human cells. We report on the oestrogenic effects of four parabens (methylparaben, ethylparaben, n-propylparaben, n-butylparaben) in oestrogen-dependent MCF7 human breast cancer cells. Competitive inhibition of [3H]oestradiol binding to MCF7 cell oestrogen receptors could be detected at 1,000,000-fold molar excess of n-butylparaben (86%), n-propylparaben (77%), ethyl-paraben (54%) and methylparaben (21%). At concentrations of 10(-6)M and above, parabens were are able to increase expression of both transfected (ERE-CAT reporter gene) and endogenous (pS2) oestrogen-regulated genes in these cells. They could also increase proliferation of the cells in monolayer culture, which could be inhibited by the antiestrogen ICI 182,780, indicating that the effects were mediated through the oestrogen receptor. However, no antagonist activity of parabens could be detected on regulation of cell proliferation by 17 beta-oestradiol at 10(-10)M. Molecular modelling has indicated the mode by which paraben molecules can bind into the ligand binding pocket of the crystal structure of the ligand binding domain (LBD) of the oestrogen receptor alpha (ERalpha) in place of 17beta-oestradiol; it has furthermore shown that two paraben molecules can bind simultaneously in a mode in which their phenolic hydroxyl groups bind similarly to those of the meso-hexoestrol molecule. Future work will need to address the extent to which parabens can accumulate in hormonally sensitive tissues and also the extent to which their weak oestrogenic activity can add to the more general environmental oestrogen problem.

Animals↗
PubMed2005

Determination of parabens in pharmaceutical formulations by solid-phase microextraction-ion mobility spectrometry.

Solid-phase microextraction (SPME) coupled with ion mobility spectrometry (IMS) was used for the detection and quantitation of 4-hydroxybenzoate preservatives, methylparaben, ethylparaben, propylparaben, and butylparaben, in commercial pharmaceutical products. For the first time, SPME-IMS is described for the simultaneous detection, separation, and quantitation of multiple analytes in complex matrixes. The parabens are extracted from the samples using SPME, and the analytes on the fiber are heated by the IMS desorber unit and vaporized into the drift tube. The four preservatives differing only by a methyl group were separated in less than 18 ms. The analytical procedure was optimized for fiber coating selection, extraction time, sample pH, sample volume, ionic strength, and IMS conditions. Separation characteristics such as resolution, theoretical plates, and drift times of the parabens were also evaluated based on the direct interfacing of SPME to IMS. The conditions were tested using six over-the-counter topical products containing various combinations of preservatives. Analysis of the samples by SPME-IMS using benzyl paraben as an internal standard yields good comparison to an HPLC method, thereby reinforcing the applicability of this technique as a method for routine analysis. Limits of detection were 10 ng/mL for methylparaben and ethylparaben and 5 ng/mL for propylparaben and butylparaben. Good linearity range and reproducibility of less than 8% were obtained.

Calibration↗
PubMed2006

The importance of the cosolvent propylene glycol on the antimicrobial preservative efficacy of a pharmaceutical formulation by DOE-ruggedness testing.

The aim of this study was to statistically evaluate the influence of the concentration of the co-solvent propylene glycol on the preservative efficacy of a complex pharmaceutical suspension-emulsion formulation containing methyl- and propylparaben. Preservative Efficacy Tests (PETs) were performed using the validated pharmacopoeial methodology with five test organisms over 1 month on lab-scale test formulations. These were independently prepared according to a Box-Behnken experimental design with a triplicate central point at 0.22% m/m methylparaben, 0.22% m/m propylparaben, and 2.75% m/m propylene glycol, and with an additional corner point of the Box-Behnken cube. We evaluated the preservative efficacies against the criteria of the United States Pharmacopeia (USP) and European Pharmacopoeias (PhEur) for formulations for oral use, as well as by the statistical comparison of the slopes obtained by linear regression of log (CFU/g) vs. time. With an initial bacterial challenge of 10(6) CFU/g for each of the three bacterial strains, no survivals were detected after 7 days. For the two fungal strains, box plots and analysis of variance showed significant, concentration-dependent, main effects: the three variables significantly influenced the kill-rate of C. albicans, while A. niger was predominantly influenced by the cosolvent propylene glycol, and only to a minor extent by methylparaben and not at all by propylparaben. These findings were confirmed by taking the pharmacopoeial criteria as the evaluation basis, where the dominant influence of propylene glycol concentration is apparent. It was concluded that the cosolvent propylene glycol is at least of equal preservative importance than both parabens.

Anti-Infective Agents↗
PubMed1988

Hypersensitivity dermatitis following suction-assisted lipectomy: a complication of local anesthetic.

We report a case of severe dermatitis involving the abdomen and thighs following suction-assisted lipectomy of these areas wherein local anesthetic containing the preservative methylparaben was used for infiltrative anesthesia. This use of local anesthetics with epinephrine can be of value in the performance of suction-assisted lipectomy to reduce blood loss, serve as an adjunct to other intraoperative anesthetic techniques, and for postoperative analgesia. Local anesthetic solutions commonly contain additives, which serve as antioxidants and antimicrobials. The most common of these preservatives is methylparaben, which can cause delayed hypersensitivity reactions. These reactions may be neither recognized nor clinically significant in small areas of infection, whereas in large body surface infiltrative procedures, such as suction-assisted lipectomy, these reactions may be of considerable consequence. This article reviews the pathophysiology and treatment of these reactions and gives recommendations for avoiding them.

Adipose Tissue↗
PubMed1991

Type IV allergy to amide-type local anesthetics.

The case of a 45-year-old woman is reported, who developed intense erythema and itching 1 day after subcutaneous (s.c.) injection of a local anesthetic containing mepivacaine and methylparaben. The reaction was attributed to a delayed-type sensitivity to mepivacaine, since mepivacaine gave a positive patch test response and also elicited a delayed sensitivity reaction after s.c. challenges, whereas prick and patch tests with methylparaben, as well as oral challenges, were negative. Interestingly, the patient also showed sensitization to lidocaine, a compound to which she had previously also been exposed.

Anesthetics, Local↗
PubMed1976

Resistance of a strain of Pseudomonas cepacia to esters of p-hydroxybenzoic acid.

Cells of a strain of Pseudomonas cepacia were isolated from an oil-in-water emulsion containing methyl and propyl p-hydroxybenzoates (methylparaben and propylparaben) as preservative additives. This strain demonstrated the ability to destroy these additives, to utilize the propyl ester as sole carbon source, and to hydrolyze the methyl ester. When the isolate was grown on Eugon agar, exposure to the methyl ester killed 99.9% of the inoculum, but the surviving cells grew logarithmically. On the other hand, cells grown on media containing propylparaben were less susceptible when subsequently exposed to emulsions containing methylparaben. These observations demonstrate one mechanism by which microorganisms develop resistance to antimicrobial preservatives.

Drug Resistance, Microbial↗
PubMed1988

Role of oxidants, eicosanoids, and neutrophils in amphotericin B lung injury in rats.

Administration of the antifungal antibiotic amphotericin B (AmB, 1 mg/kg) to intact rats produced acute lung injury as indicated by the extravascular leakage of protein and water and histological examination. The injury was neutrophil independent because it occurred in neutropenic rats. AmB produced vasoconstriction and injury in isolated lungs perfused with a cell- and plasma-free physiological solution, and this injury was independent of pulmonary perfusion pressure. In vivo administration of AmB produced an increase in lung tissue and plasma-oxidized glutathione disulfide (GSSG) indicative of oxidant stress. In the isolated lung, the radical scavengers p-hydroxybenzoate (methylparaben) and catalase attenuated AmB lung injury as did 1-phenyl-3-pyrazolidone (Phenidone), a combined radical scavenger and lipoxygenase/cyclooxygenase inhibitor, and the leukotriene antagonist CGP 35949B. Methylparaben and CGP 35949B prevented the elevation in lung tissue leukotriene C4 and B4 levels noted after AmB. We conclude that AmB in the rat produces neutrophil-independent lung injury, which is associated with oxidant stress and eicosanoid production.

Albumins↗
PubMedDate not supplied

Understanding allergic reactions to local anesthetics.

OBJECTIVE: To review the pharmacology and mechanisms by which local anesthetics cause allergic reactions. Recommendations concerning appropriate use of local anesthetics and alternative therapies in patients with documented local anesthetic allergies are given. DATA SOURCE: A MEDLINE search of English-language literature identified pertinent clinical studies, case reports, and reviews. The periods of review were Med1, 1990-present, and Med2, 1985-1989, using the MeSH terms drug hypersensitivity and anesthetics. References from the selected studies, case reports, and reviews were reviewed. STUDY SELECTION: Controlled and uncontrolled prospective studies and case reports pertaining to local anaesthetic allergies were reviewed. The selection focused on information pertaining to the etiology and diagnosis of allergic reactions to local anesthetics and alternative therapies for patients with local anesthetic allergies. DATA SYNTHESIS: Local anesthetics are classified as either ester or amide compounds. Esters are associated with a higher incidence of allergic reactions, due to a p-aminobenzoic acid (PABA) metabolite. Amide agents do not undergo such metabolism. However, preservative compounds (methylparaben) used in the preparation of amide-type agents are metabolized to PABA. Patients who are allergic to ester local anesthetics should be treated with a preservative-free amide local anesthetic. If the patient is not allergic to ester local anesthetics, these agents may be used in amide-sensitive patients. In the rare instance that hypersensitivity to both ester and amide local anesthetics occurs, or if skin testing cannot be performed, than alternative therapies including diphenhydramine, opioids, general analgesia, or hypnosis can be used. CONCLUSIONS: A true immunologic reaction to a local anesthetic is rare. Intradermal skin testing of local anesthetic compounds, methylparaben, and metabisulfite should be performed in patients when a thorough history does not rule out a possible allergic reaction to local anesthetics and future local anesthesia is necessary. Skin testing enables the clinician to identify autonomic responses to minor surgical procedures and toxic reactions to anesthetics so that patients are not incorrectly labeled as "caine" allergic. Diphenhydramine can be used as an alternative to ester and amide local anesthetics in minor procedures of short duration.

Anesthesia, Local↗
PubMed2005

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.

Animals↗
PubMed1979

Antibacterial properties of lidocaine.

The inhibitory effect of lidocaine and lidocaine plus methylparaben as a preservative was studied with 25 strains of bacteria. The tested strains were mixed with each topical anesthetic preparation, and quantitative cultures were performed on aspirates at 0, 30, 60, and 120 minutes. Results were compared to counts obtained in a lactated Ringer's solution, which were sampled at the same intervals. Lidocaine (1 percent solution) reduced quantitative counts after 120 minutes of contact by over one log for only six of the 25 strains tested. Lidocaine plus methylparaben reduced quantitative counts to a somewhat greater extent; nevertheless, all strains except Bacteroides melaninogenicus were recovered in relatively high concentrations at each sampling interval. Numerous previous studies have shown that topical anesthetic agents are toxic to bacteria. The results of this study show that this toxic effect is not sufficiently severe to prevent the recovery of most pathogens of the lower respiratory tract in bronchoscopic aspirates.

Anti-Bacterial Agents↗
PubMedDate not supplied

Sorption of parabens by fluoropolymer or fluoropolymer laminated flexible tubing.

Earlier studies using methylparaben and propylparaben showed extensive losses due to sorption by silicone, polyvinyl chloride, and other flexible tubing. As much as 100% loss of propylparaben and significant loss of methylparaben was reported within 24 hours using Tygon, Clearflo, or Silastic tubing. The fluoropolymer Teflon FEP did not show sorption losses. The current study was conducted using three different fluoropolymer resin tubing pieces (FEP, PFA, and NXT or PTFE) as well as a Tygon tubing lined with FEP to show that these do not show paraben sorption losses over an extended period of time. The results of this study show that sorption losses can be avoided or reduced by proper selection of flexible tubing.

Adsorption↗
PubMed2003

[Studies for analyzing phenoxyethanol and parabens in commercial lotions].

Both phenoxyethanol and parabens are kinds of preservatives in cosmetics and are nominated as the restricted ingredients in cosmetics in Japanese Pharmaceutical Affairs Low. So the analytical methods for phenoxyethanol and parabens were investigated by HPLC. After adding methanol to phenoxyethanol and parabens in lotions, the testing solutions were analyzed by HPLC using the ODS column (CAPCELL PAK C18 column, 4.6 x 250 mm), the mixture either of 50 mmol/l phosphate(pH3.5) and acetonitrile (7:3) for phenoxyethanol or of 50 mmol/l phosphate buffer(pH3.5) and acetonitrile (3:2) for parabens and the detection wavelength of either 270 nm for pehnoxyethanol or 255 nm for parabens. The working curves from 0.5 to 5 micrograms/ml passed through the origin. There were no interference of peaks of phenoxyethanol and parabens from the cosmetics. Eleven lotions out of 42 lotions did not have phenoxyethanol. Phenoxyethanol in thirty-one cosmetics ranged from 0.009 to 1.043% and those average was 0.264%. Parabens, especially methylparaben, were detected in all lotions. The amounts of parabens ranged from 0.016 to 0.267% and their average was 0.120%. There were 7 kinds of lotions whose contents of phenoxyethanol and methylparaben were below 0.1%.

Acetonitriles↗
PubMedDate not supplied

Inhibition of hepatic microsomal carboxylesterase activity by paraoxon.

A large number of therapeutic agents are esters of carboxylic acids and are thus substrates for microsomal carboxylesterase enzymes. These studies characterized the effects of the organophosphate compound, paraoxon, on the hydrolysis of several drug esters (procaine, chloramphenicol succinate, prednisolone succinate, lidocaine, procainamide and methylparaben) by microsomal preparations from guinea-pigs. These investigations demonstrate that carboxylesterase activity toward several drug esters is present in liver, lung and kidney. The liver is by far the major site of hydrolysis of these ester compounds. Since no hydrolysis was observed with the two amide esters, the hydrolysis of carboxylesters and amide esters appears to be mediated by different enzymes in the guinea-pig. At the substrate concentrations studied, the hydrolysis of methylparaben followed zero-order kinetics. When added to isolated microsomal preparations, paraoxon produced a dose-dependent inhibition of hydrolysis of all substrates. Administration of paraoxon to guinea-pigs prior to isolation of microsomes did not produce consistent effects with any substrate. Inhibition of ester hydrolysis was observed with some pretreatments, while either no change or increased hydrolysis was observed with other pretreatment regimens.

Animals↗
PubMed1998

Cocaine and lidocaine with phenylephrine as topical anesthetics: antimicrobial activity against common nasal pathogens.

Topical anesthetics are commonly used in the evaluation of nasal pathology. The anesthetics routinely used, 4% lidocaine with phenylephrine, or 4% cocaine, have been demonstrated to have varying inhibitory effects on bacterial cultures. The present study examined the antimicrobial activity of these topical anesthetics used in nasal procedures. The pathogens used were Branhamella catarrhalis, Enterobacter sp., Haemophilus influenzae, Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus and Streptococcus pneumoniae. Organisms were against two-fold serial dilutions of stock preparations of 4% lidocaine with 0.25% phenylephrine, 0.25% phenylephrine, 0.1% methylparaben, 250 mg/ml ampicillin, and 4% cocaine. The minimum inhibitory concentration and minimum bactericidal concentration for each of the solutions were obtained. The bacteria studied varied gently in their susceptibility to lidocaine with phenylephrine versus cocaine: Cocaine consistently exhibited greater antimicrobial activity than lidocaine. Phenylephrine and methylparaben showed slight antimicrobial activity. These topical anesthetics have slight bactericidal activity against nasal pathogens, which can sometimes lead to false-negative results. Otolaryngologists should recognize the possible antimicrobial effects of topical anesthetics when culturing specimens. This is especially important when the specimen will be used for guidance of antimicrobial therapy, as in the case of the critically ill patient who requires aspiration for organism-specific therapy. Further studies, specifically in vivo experiments, are needed to determine if use of the drugs produces a significant change in the ability to culture organisms from these sites. This type of study would, however, be difficult to perform, since most patients requiring aspiration are already on high-dose antibiotics that would inhibit the growth of most microorganisms. A modified aspiration technique using a less concentrated topical anesthetic will likely be required to increase the chances of obtaining positive cultures.

Administration, Topical↗
PubMedDate not supplied

Concentrations of parabens in human breast tumours.

Parabens are used as preservatives in many thousands of cosmetic, food and pharmaceutical products to which the human population is exposed. Although recent reports of the oestrogenic properties of parabens have challenged current concepts of their toxicity in these consumer products, the question remains as to whether any of the parabens can accumulate intact in the body from the long-term, low-dose levels to which humans are exposed. Initial studies reported here show that parabens can be extracted from human breast tissue and detected by thin-layer chromatography. More detailed studies enabled identification and measurement of mean concentrations of individual parabens in samples of 20 human breast tumours by high-pressure liquid chromatography followed by tandem mass spectrometry. The mean concentration of parabens in these 20 human breast tumours was found to be 20.6 +/- 4.2 ng x g(-1) tissue. Comparison of individual parabens showed that methylparaben was present at the highest level (with a mean value of 12.8 +/- 2.2 ng x g(-1) tissue) and represents 62% of the total paraben recovered in the extractions. These studies demonstrate that parabens can be found intact in the human breast and this should open the way technically for more detailed information to be obtained on body burdens of parabens and in particular whether body burdens are different in cancer from those in normal tissues.

Breast Neoplasms↗