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1.
Clin Ter ; 171(1): e16-e22, 2021.
Article in English | MEDLINE | ID: mdl-33346321

ABSTRACT

BACKGROUND: Esophagogastroduodenoscopy (EGDS) is the gold standard exam for upper gastrointestinal diseases. EGDS is very important in Early Gastric Cancer diagnosis and treatment but it is an operator-dependent exam and there are lots of factors that reduce its visibility (mucus, bubbles and foam). AIM: The aim of our study is to evaluate if the use of Lumevis™ improves mucosa visualization during EGDS without increasing the examination time and complications' rate and comparing the differences in patients prepared with water or no intervention. MATERIALS AND METHODS: we recruited 50 patients from 01/08/2020 to 31/08/2020 who came to our observation for epigastric pain, dyspepsia and gastroesophageal reflux (GERD). For each patient we evaluate the satisfaction of the procedure, vision quality, EGDS duration and the presence of bubbles following the administration of: nothing (group 1); 50 ml of water alone (W) (group 2); W + simethicone (S) 150 mg+N-acetylcysteine (NAC) 250 mg+10% acetic acid 2.5 ml (group 3); W+S 100 mg + NAC 300 mg + 10% acetic acid 2 ml (group 4); W + S 100 mg + NAC 200 mg + 10% acetic acid 1.5 ml (group 5). RESULTS: Our results suggest that the lesion detection rate improves with the use of simethicone, acetylcysteine and acetic acid prior to EGDS, although this needs to be studied prospectively. CONCLUSIONS: Lumevis™ is proposed as a new product in the routine preparation of all patients who have to undergo an EGDS, raising the level in the quality of the exam.


Subject(s)
Endoscopy, Digestive System/methods , Gastrointestinal Diseases/diagnostic imaging , Premedication/methods , Acetic Acid/chemistry , Acetylcysteine/chemistry , Adult , Dyspepsia/diagnostic imaging , Female , Gastroesophageal Reflux/diagnostic imaging , Humans , Male , Middle Aged , Simethicone/chemistry , Stomach Neoplasms/diagnostic imaging
2.
Am J Health Syst Pharm ; 74(9): e202-e210, 2017 May 01.
Article in English | MEDLINE | ID: mdl-28438825

ABSTRACT

PURPOSE: Beyond-use dating (BUD) of lidocaine alone and in two "magic mouthwash" preparations stored in amber oral syringes at room temperature was determined. METHODS: Two formulations of mouthwash containing oral topical lidocaine 2% (viscous), diphenhydramine 2.5 mg/mL, and aluminum hydroxide-magnesium hydroxide-simethicone were prepared in 1:1:1 and 1:2.5:2.5 ratios, divided into 3-mL samples, and stored in unit-dose oral amber syringes. Unit-dose single-product lidocaine samples were also prepared to serve as controls and stored in oral amber syringes. The lidocaine concentrations in these samples were measured periodically for 90 days. A stability-indicating high-performance liquid chromatographic method was developed and validated for system suitability, accuracy, repeatability, intermediate precision, specificity, linearity, and robustness. RESULTS: Based on the calculated percentages versus the initial concentration and the results from an analysis of variance comparing the two formulations, a BUD of 21 days is deemed appropriate for both magic mouthwash formulations. Based on the stability data, published safety concerns, and lack of efficacy in combination, packaging and dispensing lidocaine separately from other ingredients are recommended when administering magic mouthwash mixtures. Utilizing a 90-day BUD, lidocaine can be packaged separately from other magic mouthwash ingredients in individual dosage units and applied to the oral cavity using the swish-and-spit method. The delivery of the diphenhydramine and aluminum hydroxide-magnesium hydroxide-simethicone could be separated, allowing for a swish-and-swallow method of administration. CONCLUSION: A BUD of 21 days is recommended for lidocaine prepared with diphenhydramine and aluminum hydroxide-magnesium hydroxide-simethicone in ratios of 1:1:1 and 1:2.5:2.5 and stored at room temperature in amber oral plastic syringes.


Subject(s)
Analgesics/chemistry , Drug Compounding/methods , Drug Packaging/methods , Lidocaine/chemistry , Mouthwashes/chemistry , Administration, Oral , Aluminum Hydroxide/administration & dosage , Aluminum Hydroxide/chemistry , Analgesics/administration & dosage , Antineoplastic Agents/adverse effects , Diphenhydramine/administration & dosage , Diphenhydramine/chemistry , Drug Combinations , Drug Stability , Drug Storage/methods , Drug Storage/standards , Humans , Lidocaine/administration & dosage , Magnesium Hydroxide/administration & dosage , Magnesium Hydroxide/chemistry , Mouth Mucosa/drug effects , Mouth Mucosa/radiation effects , Mouthwashes/administration & dosage , Neoplasms/therapy , Simethicone/administration & dosage , Simethicone/chemistry , Stomatitis/chemically induced , Stomatitis/drug therapy , Syringes , Temperature
4.
Korean J Gastroenterol ; 67(4): 189-97, 2016 Apr 25.
Article in Korean | MEDLINE | ID: mdl-27112245

ABSTRACT

BACKGROUND/AIMS: There are no studies that looked into the bubble eliminating efficacy of polyethylene glycol with ascorbic acid (PEGA), which has been one of the shortcomings of polyethylene glycol (PEG). In this study, we compared newly introduced PEGA regimen by adding either simethicone or 1 L of water. METHODS: A prospective randomized controlled study was carried out at Dongguk Universtiy Gyeongju Hospital from July 2014 to September 2014. A total of 90 patients were randomly assigned to 3 groups; PEGA group (n=30) which served as control, simethicone addition group (n=30) to which simethicone 400 mg was additionally prescribed, and water addition group (n=30) to whom additional 1 L of water was given. Cleansing effectiveness, gas elimination efficacy, side effects, and patient satisfaction were compared between the groups. RESULTS: PEGA group demonstrated the highest cleansing effectiveness, but there was no statistically significant difference among the groups. Simethicone addition group showed significantly lesser amount of bubbles than the other groups (2.57±2.05 vs. 1.10±1.83 vs. 2.60±2.84, p=0.017). The rates of side effects in each group were 20.00% vs. 16.77% vs. 53.33%. Water addition group had significantly more side effects than the PEGA group and the simethicone addition group (p=0.003). The patient satisfaction score of each group was 3.37±0.85 vs. 3.73±0.74 vs. 3.20±0.66 with simethicone addition group showing significantly higher satisfaction than water addition group (p=0.020). CONCLUSIONS: PEGA bowel preparation agent showed satisfactory bowel cleansing despite the decrease in dosage, and addition of simethicone resulted in better bubble elimination.


Subject(s)
Ascorbic Acid/chemistry , Cathartics/pharmacology , Colon/drug effects , Polyethylene Glycols/chemistry , Simethicone/chemistry , Water/chemistry , Adult , Cathartics/adverse effects , Cathartics/chemistry , Colonoscopy , Female , Humans , Male , Middle Aged , Patient Compliance , Polyethylene Glycols/adverse effects , Polyethylene Glycols/pharmacology , Prospective Studies
5.
Article in Korean | WPRIM (Western Pacific) | ID: wpr-165883

ABSTRACT

BACKGROUND/AIMS: There are no studies that looked into the bubble eliminating efficacy of polyethylene glycol with ascorbic acid (PEGA), which has been one of the shortcomings of polyethylene glycol (PEG). In this study, we compared newly introduced PEGA regimen by adding either simethicone or 1 L of water. METHODS: A prospective randomized controlled study was carried out at Dongguk Universtiy Gyeongju Hospital from July 2014 to September 2014. A total of 90 patients were randomly assigned to 3 groups; PEGA group (n=30) which served as control, simethicone addition group (n=30) to which simethicone 400 mg was additionally prescribed, and water addition group (n=30) to whom additional 1 L of water was given. Cleansing effectiveness, gas elimination efficacy, side effects, and patient satisfaction were compared between the groups. RESULTS: PEGA group demonstrated the highest cleansing effectiveness, but there was no statistically significant difference among the groups. Simethicone addition group showed significantly lesser amount of bubbles than the other groups (2.57±2.05 vs. 1.10±1.83 vs. 2.60±2.84, p=0.017). The rates of side effects in each group were 20.00% vs. 16.77% vs. 53.33%. Water addition group had significantly more side effects than the PEGA group and the simethicone addition group (p=0.003). The patient satisfaction score of each group was 3.37±0.85 vs. 3.73±0.74 vs. 3.20±0.66 with simethicone addition group showing significantly higher satisfaction than water addition group (p=0.020). CONCLUSIONS: PEGA bowel preparation agent showed satisfactory bowel cleansing despite the decrease in dosage, and addition of simethicone resulted in better bubble elimination.


Subject(s)
Adult , Female , Humans , Male , Middle Aged , Ascorbic Acid/chemistry , Cathartics/adverse effects , Colon/drug effects , Colonoscopy , Patient Compliance , Polyethylene Glycols/adverse effects , Prospective Studies , Simethicone/chemistry , Water/chemistry
6.
Ultrasound Q ; 30(2): 135-8, 2014 Jun.
Article in English | MEDLINE | ID: mdl-24850028

ABSTRACT

PURPOSE: The purpose of this study was to prospectively compare the efficacy of 2 oral ultrasonography (US) contrast agents (simethicone-water rotation [SWR] and simethicone-coated cellulose [SCC]) in improving visualization of the pancreas. METHODS: Two sessions (SWR and SCC) of transabdominal US studies were performed on 38 healthy volunteers. In each session, US images were obtained in precontrast supine and upright positions and postcontrast supine and upright positions. The visualization of the pancreas was graded on a scale of 1 to 5 (1 = nonvisualization, 5 = excellent visualization), grading the head, body, and tail separately. RESULTS: In the supine position, SWR significantly improved the visualization of the pancreatic head, body, and tail, whereas there were no significant differences between SCC and precontrast images. Simethicone-water rotation showed significantly better visualization than SCC. The average scores of the head, body, and tail of the pancreas that graded 4 or more were 15.8% of precontrast, 21.1% of SCC, and 50% of SWR. In the upright position, both SWR and SCC significantly improved the visualization of the pancreas, except for the pancreatic body on SCC. There were no significant differences between SWR and SCC. The average scores that graded 4 or more were 26.3% of precontrast, 57.9% of SCC, and 65.8% of SWR. CONCLUSION: Simethicone-water rotation was more effective than SCC in improving the visualization of the pancreas.


Subject(s)
Cellulose , Image Enhancement/methods , Pancreas/diagnostic imaging , Simethicone , Water , Administration, Oral , Adult , Cellulose/administration & dosage , Cellulose/chemistry , Contrast Media/administration & dosage , Female , Humans , Male , Observer Variation , Reference Values , Sensitivity and Specificity , Simethicone/administration & dosage , Simethicone/chemistry , Ultrasonography , Water/administration & dosage , Water/chemistry
7.
Biotechnol Prog ; 30(5): 1145-60, 2014.
Article in English | MEDLINE | ID: mdl-24623631

ABSTRACT

Simethicone emulsion is used to regulate foaming in cell culture operations in biopharmaceutical processes. It is also a potential source of endotoxin contamination. The inactivation of endotoxins in dilute simethicone emulsions was assessed as a function of time at different steam temperatures using a Limulus amebocyte lysate kinetic chromogenic technique. Endotoxin inactivation from steam-heat treatment was fit to a four-parameter double exponential decay model, which indicated that endotoxin inactivation was biphasic, consisting of fast and slow regimes. In the fast regime, temperature-related effects were dominant. Transitioning into the slow regime, the observed temperature dependence diminished, and concentration-related effects became increasingly significant. The change in the Gibbs free energy moving through the transition state indicated that a large energy barrier must be overcome for endotoxin inactivation to occur. The corresponding Arrhenius pre-exponential factor was >>10(12) s(-1) suggesting that endotoxins in aqueous solution exist as aggregates. The disorder associated with the endotoxin inactivation reaction pathway was assessed via the change in entropy moving through the transition state. This quantity was positive indicating that endotoxin inactivation may result from hydrolysis of individual endotoxin molecules, which perturbs the conformation of endotoxin aggregates, thereby modulating the biological activity observed. Steam-heat treatment decreased endotoxin levels by 1-2 logarithm (log) reduction (LRV), which may be practically relevant depending on incoming raw material endotoxin levels. Antifoam efficiency and cell culture performance were negligibly impacted following steam-heat treatment. The results from this study show that steam-heat treatment is a viable endotoxin control strategy that can be implemented to support large-scale biopharmaceutical manufacturing.


Subject(s)
Emulsions/chemistry , Endotoxins/chemistry , Simethicone/chemistry , Steam , Sterilization/methods , Animals , Biotechnology , CHO Cells , Chemistry, Pharmaceutical , Cricetinae , Cricetulus , Nonlinear Dynamics , Recombinant Proteins/standards , Temperature
8.
J Pharm Biomed Anal ; 58: 200-7, 2012 Jan 25.
Article in English | MEDLINE | ID: mdl-21962761

ABSTRACT

The pharmaceutical industry is one of the more important sectors for the use of polydimethylsiloxanes (PDMS), which belong to the organosilicon polymers. In drugs for internal use, they are used as an active pharmaceutical ingredient (API) called dimeticone or simeticone. Due to their specific chemical nature, PDMS can have different degrees of polymerization, which determine the molecular weight and viscosity. The Pharmacopoeial monographs for dimeticone and simeticone, only give the permitted polymerization and viscosity range. It is, however, essential to know also the degree of polymerization or the specific molecular weight of PDMS that are present in pharmaceutical formulations. In the literature there is information about the impact of particle size, and thus molecular weight, on the toxicity, absorption and migration in living organisms. This study focused on the use of a developed method - the exclusion chromatography with evaporative light scattering detector (SEC-ELSD) - for identification and determination of dimeticone and simeticone in various pharmaceutical formulations. The method had a high degree of specificity and was suitable for speciation analysis of these polymers. So far the developed method has not been used in the control of medicinal products containing dimeticone or simeticone.


Subject(s)
Chromatography, Gel/methods , Dimethylpolysiloxanes/analysis , Dimethylpolysiloxanes/chemistry , Pharmaceutical Preparations/analysis , Simethicone/analysis , Simethicone/chemistry , Chemistry, Pharmaceutical/methods , Light , Molecular Weight , Particle Size , Pharmaceutical Preparations/chemistry , Polymerization , Scattering, Radiation , Sensitivity and Specificity , Viscosity
9.
Biomacromolecules ; 7(2): 618-26, 2006 Feb.
Article in English | MEDLINE | ID: mdl-16471939

ABSTRACT

The structure and the associated dynamics of a series of poly(gamma-benzyl-L-glutamate)-b-poly(dimethyl siloxane)-b-poly(gamma-benzyl-L-glutamate) (PBLG-b-PDMS-b-PBLG) triblock copolymers were investigated using small- and wide-angle X-ray scattering, NMR, transmission electron microscopy, and dielectric spectroscopy, respectively. The structural analysis revealed phase separation in the case of the longer blocks with defected alpha-helical segments embedded within the block copolymer nanodomains. The alpha-helical persistence length was found to depend on the degree of segregation; thermodynamic confinement and chain stretching results in the partial annihilation of helical defects.


Subject(s)
Polyglutamic Acid/analogs & derivatives , Polyglutamic Acid/chemistry , Siloxanes/chemistry , Simethicone/chemistry , Thermodynamics , Carbon Isotopes , Magnetic Resonance Spectroscopy/methods , Magnetic Resonance Spectroscopy/standards , Microscopy, Electron, Transmission , Molecular Conformation , Particle Size , Polyglutamic Acid/chemical synthesis , Reference Standards , Scattering, Radiation , Sensitivity and Specificity , Siloxanes/chemical synthesis , Simethicone/analogs & derivatives , X-Rays
10.
Int J Pharm ; 298(2): 367-71, 2005 Jul 25.
Article in English | MEDLINE | ID: mdl-15941632

ABSTRACT

Novel anhydrous emulsions, which may offer some advantages as depot or reservoir vehicles for lipophilic drugs in controlled delivery systems, were formulated using castor oil as the disperse phase and dimethicone or cyclopentasiloxane as the continuous phase. Among the emulsifiers studied only silicone surfactants (cyclomethicone/dimethicone copolyols) which were miscible in silicone oil stabilized the emulsions. Cyclomethicone/PEG/PPG-18/18 Dimethicone and Cyclopentasiloxane/PEG/PPG-18/18 Dimethicone were more effective in lowering the interfacial tension between castor oil and both dimethicone and cyclopentasiloxane. Emulsions formulated using either of these two surfactants were found to be stable against phase separation and exhibited least globule growth over 168 h. The average particle size was found to be 2-6 microm in these systems formed by probe sonication. Slow release patterns of 3H-dehydroepiandrosterone (DHEA) and 3H-dexamethasone solubilized in the disperse castor oil phase into an aqueous dialyzing medium were observed over 48 h.


Subject(s)
Delayed-Action Preparations , Castor Oil , Chemistry, Pharmaceutical , Dehydroepiandrosterone/administration & dosage , Dehydroepiandrosterone/chemistry , Dexamethasone/administration & dosage , Dexamethasone/chemistry , Dimethyl Sulfoxide , Dimethylformamide , Drug Delivery Systems , Emulsions , Silicone Oils , Simethicone/chemistry , Surface Tension , Surface-Active Agents/chemistry
11.
Int J Toxicol ; 22 Suppl 2: 11-35, 2003.
Article in English | MEDLINE | ID: mdl-14555417

ABSTRACT

Dimethicone is a fluid mixture of fully methylated linear siloxane polymers end-blocked with trimethylsiloxy units. Methicone is a linear monomethyl polysiloxane. The other dimethicones and methicones covered in this review are siloxane polymers of Dimethicone and Methicone. Most of these ingredients function as conditioning agents in cosmetic formulations at current concentrations of use of < or =15%. Clinical and animal absorption studies reported that Dimethicone was not absorbed following oral or dermal exposure. Dimethicone, Methicone, and Vinyldimethicone were not acutely toxic following oral exposure. No adverse reactions were found in rabbits following short-term dermal dosing with 6% to 79% Dimethicone, yet adverse effects were noted with a hand cream formulation containing 1% Dimethicone, suggesting something else in the preparation was toxic. Mice and rats were dosed for 90 days with up to 10% Dimethicone without adverse effect. Dimethicone did not produce adverse effects in acute and short-term inhalation-route studies, Methicone and Vinyldimethicone were negative in acute exposure studies using rats, but Hexyl Methicone was toxic to rats at 5 mg/L delivered in small particle (mean diameter of 0.29 micro) aerosols. Most dermal irritation studies using rabbits classified Dimethicone as a minimal irritant. Dimethicone (tested undiluted and at 79%) was not a sensitizer in four assays using mice and guinea pigs. It was not a sensitizer at 5.0% in a clinical repeated insult patch test using 83 panelists. Most ocular irritation studies using rabbits classified Dimethicone as a mild to minimal irritant. Dimethicone was tested in numerous oral-dose (using rats) and dermal-dose (using rats, rabbits, and monkeys) reproductive and developmental toxicity studies. In a few studies, treated males had significantly decreased body weight and/or decreased testes or seminal vesicles weights. No treatment-related adverse findings were noted in dosed pregnant females or fetuses. Dimethicone was negative in all genotoxicity assays. It was negative in both an oral (tested at 91%) and dermal (tested at an unknown concentration) dose carcinogenicity assay using mice. The Cosmetic Ingredient Review (CIR) Expert Panel considered it unlikely that any of these polymers would be significantly absorbed into the skin due to their large molecular weight. Although adverse effects were noted in one inhalation study with small aerosol particles, the expected particle sizes for cosmetic products would primarily be in the range of 60 to 80 micro, and less than 1% would be under 10 micro, which is an upper limit for respirable particles. Overall, the safety test data support the safety of these ingredients at the concentrations they are known to be used in cosmetic formulations. Accordingly, the CIR Expert Panel was of the opinion that Stearoxy Dimethicone, Dimethicone, Methicone, Amino Bispropyl Dimethicone, Aminopropyl Dimethicone, Amodimethicone, Amodimethicone Hydroxystearate, Behenoxy Dimethicone, C24-28 Alkyl Methicone, C30-45 Alkyl Methicone, C30-45 Alkyl Dimethicone, Cetearyl Methicone, Cetyl Dimethicone, Dimethoxysilyl Ethylenediaminopropyl Dimethicone, Hexyl Methicone, Hydroxypropyldimethicone, Stearamidopropyl Dimethicone, Stearyl Dimethicone, Stearyl Methicone, and Vinyldimethicone are safe as used in cosmetic formulations.


Subject(s)
Consumer Product Safety , Cosmetics/toxicity , Emollients/toxicity , Simethicone/toxicity , Animals , Cosmetics/chemistry , Emollients/chemistry , Humans , Simethicone/chemistry , Toxicity Tests
12.
Am J Contact Dermat ; 11(3): 165-9, 2000 Sep.
Article in English | MEDLINE | ID: mdl-11012005

ABSTRACT

BACKGROUND: Irritant and/or allergic hand dermatitis in individuals who are unable to avoid causative exposures is difficult to control. Usefulness of protective creams has been generally unsatisfactory. OBJECTIVE: To determine if hand dermatitis, primarily of an occupational nature, could be improved by the use of a protective foam containing dimethicone and glycerin. METHODS: Adult male and female subjects with chronic hand dermatitis for at least 12 months, felt to be either allergic, irritant, or combined in nature were given the study foam for routine application after a 2-week observation period. At 2 and 6 weeks the skin was evaluated by the investigator and subject for parameters including redness, scaling, fissuring, blistering, and pruritus on a numerical scale. A global evaluation also was performed. Photographs were taken at each visit. Usage of topical corticosteroids was recorded. No systemic therapies other than antihistamines were allowed. RESULTS: Thirty-one subjects were enrolled in the study and 28 completed it. The physician and subject's initial global evaluations averaged 6.13 and 5.48, respectively (0-10 scale). The final scores were 3.68 and 4.75, respectively (P < .001 for physician rating; P = .259 for subject rating). Topical corticosteroid usage was reduced in 16 of 30 (53.6%) subjects. Twenty-one of 30 subjects (70.0%) had improved over the course of the study. No adverse effects were noted. CONCLUSION: This protective foam greatly or moderately improved chronic hand dermatitis in a sizable number of individuals with previously uncontrolled dermatitis despite continuing in their regular occupation.


Subject(s)
Dermatitis, Contact/drug therapy , Dermatitis, Irritant/drug therapy , Dermatitis, Occupational/drug therapy , Glycerol/therapeutic use , Hand Dermatoses/drug therapy , Simethicone/therapeutic use , Administration, Topical , Adult , Anti-Inflammatory Agents/therapeutic use , Chronic Disease , Dermatitis, Contact/classification , Dermatitis, Contact/pathology , Dermatitis, Irritant/classification , Dermatitis, Irritant/pathology , Dermatitis, Occupational/classification , Dermatitis, Occupational/pathology , Dimethylpolysiloxanes , Female , Follow-Up Studies , Glycerol/chemistry , Hand Dermatoses/classification , Hand Dermatoses/pathology , Humans , Hydrocortisone , Male , Occupations/statistics & numerical data , Severity of Illness Index , Simethicone/chemistry , Treatment Outcome
13.
J Control Release ; 63(1-2): 7-17, 2000 Jan 03.
Article in English | MEDLINE | ID: mdl-10640576

ABSTRACT

From the use of silicones within O/W/O multiple emulsions, we can expect, two principal advantages: (1) the silicones with the lowest molecular weight decrease the oily touch; (2) due to the large range of viscosity, this excipient should influence the skin distribution of actives after topical application. The purpose of our work is to highlight these advantages. Multiple emulsions were formulated with several dimethicones and with drug model. Firstly, the effects of different dimethicones incorporated within multiple emulsions were studied, through in vitro penetration results. Secondly, we investigated the residual film on the skin by Differential Scanning Calorimetry (DSC) and by Fourier Transform Infrared (FTIR) to determine its structure. Correlations were established between the silicone structure and the distribution of drugs in different skin levels or between the silicone structure and the percutaneous penetration. The incorporation of silicones within O/W/O multiple emulsions seems to be an efficient means of modulating the penetration and the distribution of drugs in the skin.


Subject(s)
Emollients/chemistry , Emollients/pharmacokinetics , Simethicone/analogs & derivatives , Simethicone/pharmacokinetics , Triterpenes/chemistry , Triterpenes/pharmacokinetics , Animals , Calorimetry, Differential Scanning , Delayed-Action Preparations , Emulsions , Female , Lipid Metabolism , Paraffin/chemistry , Paraffin/pharmacokinetics , Rats , Simethicone/chemistry , Skin/metabolism , Skin Absorption , Spectroscopy, Fourier Transform Infrared , Thermodynamics , Viscosity
14.
J Appl Toxicol ; 14(3): 207-11, 1994.
Article in English | MEDLINE | ID: mdl-8083482

ABSTRACT

The mechanism of the foam-inhibiting action of simethicone, mainly used against flatulence, has been studied. Its effect on foaming systems containing synthetic gastric juice and a surface-active substance (anionic surfactant, cationic surfactant, soap solution) was quantitated by measuring the surface tension, foam stability and initial foam density. The effect of simethicone on each of the examined systems was the result of the combination of two actions: the drainage of liquid from foam films and the rupture of relatively thick liquid films. The mechanism of these actions may be described as the liquid drainage followed by bridging of the liquid film by polydimethylsiloxane droplets, helped by hydrophobic silica particles also present in the antifoaming agent, leading to the rupture of the film surface and air escape.


Subject(s)
Antifoaming Agents/chemistry , Simethicone/chemistry , Models, Chemical
15.
Dermatology ; 189(4): 373-7, 1994.
Article in English | MEDLINE | ID: mdl-7873823

ABSTRACT

BACKGROUND: Pastes are semisolid stiff preparations containing a high proportion of finely powdered material. Powders such as zinc oxide, titanium dioxide, starch, kaolin or talc are incorporated in high concentrations into a preferably lipophilic, greasy vehicle. A clinically distinctive feature which is generally attributed to pastes is the quality to absorb exudates by nature of the powder or other absorptive components. Reviewing the various pharmacopoeias serious doubts arise from the various formulas of pastes and their absorptive features. The zinc oxide pastes of the USP XXII, the DAB 10 and BP 88 (US, German and British pharmacopoeias). are composed of petrolatum, zinc oxide and starch. Petrolatum, a highly lipophilic, water-immiscible vehicle surrounds the powder particles preventing any absorption of water or exudates. OBJECTIVE: The goal of our investigation was to test a simple experimental setting to characterize the clinically important absorptive feature of powders and pastes. METHODS: The absorptive features of the powders were determined by the method of Enslin. The absorptive features of the paste preparations were calculated from the weight difference between the paste preparation before and after incubation with water using a simple standardized procedure. RESULTS: The absorptive features of titanium dioxide, zinc oxide, kaolin, corn starch and methylcellulose powder in pharmacopoeia quality were determined. Zinc oxide and kaolin powder showed the highest absorption of 1,000 mg water/g powder (100%). The water absorption of corn starch and titanium dioxide was 700 and 450 mg/g powder, respectively. The absorptive features of a series of paste preparations were studied in a simple experimental setting. The data show that two-phase pastes consisting of two immiscible components, one (the dispersed or inner phase; powder) being suspended in the other (the continuous or outer phase; lipophilic vehicle), have no absorptive features. In contrast, three-phase pastes consisting of a hydrophilic two-phase emulsion with high concentrations of incorporated powder (cream pastes) show considerable water uptake. CONCLUSIONS: We conclude that the classical two-phase pastes such as the zinc oxide pastes have no absorptive features. On the contrary, these formulations are highly occlusive. Therefore lipophilic pastes are only indicated when protection of intact skin against aggressive body exudates and humidity is required. The hydrophilic three-phase pastes or cream pastes show considerable water uptake and fulfil common expectations of pastes to dry the skin.


Subject(s)
Dermatologic Agents/analysis , Dermatologic Agents/chemistry , Ointments/analysis , Ointments/chemistry , Powders/analysis , Powders/chemistry , Absorption , Calcium Hydroxide/chemistry , Emulsions/chemistry , Kaolin/chemistry , Lipids/chemistry , Methylcellulose/chemistry , Mineral Oil/chemistry , Oleic Acid , Oleic Acids/chemistry , Peanut Oil , Plant Oils/chemistry , Polyethylene Glycols , Simethicone/chemistry , Starch/chemistry , Suspensions/chemistry , Titanium/chemistry , Water/chemistry , Zinc Oxide/chemistry
16.
Scand J Dent Res ; 99(2): 96-9, 1991 Apr.
Article in English | MEDLINE | ID: mdl-2052902

ABSTRACT

Deposition of alkali-soluble fluoride on enamel in the presence and absence of an acquired pellicle was studied in vitro during a single topical application of a 2% sodium fluoride solution at neutral pH. Five experimental groups of repeated measures design were established. The amount of alkali-soluble fluoride formed on enamel (i.e., calcium fluoride) was measured by chemical assessments and by SEM. The results showed that there were no differences among the groups demonstrating the incapacity of pellicle to interfere with deposition of alkali-soluble fluoride on enamel. The fluoride ions are thus able to reach the enamel in spite of the presence of the pellicle.


Subject(s)
Calcium Fluoride/metabolism , Dental Deposits/metabolism , Dental Enamel/metabolism , Fluorides, Topical/pharmacokinetics , Sodium Fluoride/pharmacokinetics , Alkalies , Dental Enamel/ultrastructure , Dental Pellicle , Humans , Microscopy, Electron, Scanning , Saliva/metabolism , Simethicone/chemistry , Solubility
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