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PubMed1978

Bioavailability of erythromycin stearate: influence of food and fluid volume.

The influence of various test meals and coadministered water volumes on erythromycin stearate bioavailability from orally dosed film-coated tablets was studied in healthy human subjects. Serum erythromycin levels were uniformly reduced by all test meals, with the reduction in mean peak serum levels varying from 47 to 60%. Serum erythromycin levels also were reduced significantly in fasted individuals when the accompanying water volume was reduced from 250 to 20 ml. The apparent drug absorption rate constant was not influenced by treatments. This result is probably due to rapid degradation of solubilized, unabsorbed drug in the GI tract. Higher and more uniform serum erythromycin levels are obtained when erythromycin stearate tablets are given on an empty stomach together with an adequate water volume.

Adult↗
PubMed1992

Physical and lubrication properties of magnesium stearate.

The lubrication properties of two commercial-grade magnesium stearates were studied. Their moisture contents and crystal structures were similar. There were minor differences in their fatty acid composition, but the differences did not affect the lubrication properties. The lubrication properties correlated with particle size distributions and specific surface area. The effect of these parameters was further studied with unmilled and milled chemically pure magnesium stearate. Milling decreased the particle size and increased the specific surface area. In both cases, the batch with a smaller particle size and larger specific surface area had considerably better lubricity.

Adjuvants, Pharmaceutic↗
PubMed1990

Reduction of doxyl stearates by ascorbate in unilamellar liposomes.

The effects of the position in the membrane of the doxyl group on the rate of reduction by external ascorbate were studied in large unilamellar liposomes. The key factor increasing the rate of reduction was the degree of partitioning of the nitroxide into the aqueous phase; the doxyl group's proximity to the surface of the membrane was not a major factor. Consistent with the latter finding, factors that increased the rate of membrane permeation by ascorbate did not have major effects on the observed rates of reduction. We conclude that in this system the external aqueous medium is the primary site of reduction of the doxyl stearates and the doxyl stearates are in effective equilibrium between the membrane and aqueous phases.

Ascorbic Acid↗
PubMed2001

Effect of polymer molecular weight and addition of calcium stearate on response of MG63 osteoblast-like cells to UHMWPE particles.

Periprosthetic osteolysis and implant loosening is associated with the presence of ultrahigh molecular weight polyethylene (UHMWPE) wear debris particles. Osteoblast phenotypic expression in vitro is affected by UHMWPE particles, suggesting that bone formation may also be affected by wear debris. Here we tested the hypothesis that the response of osteoblasts to UHMWPE can be modified by changes in UHMWPE particle chemistry. We used four different commercially available preparations of GUR UHMWPE particles to determine if chemical composition (+/- Ca-stearate) or polymer molecular weight (3.1-4.2 million or 5.4-6.5 million g/mol) modulates osteoblast response. Particles were characterized by size distribution, morphology, and number of particles added to the culture medium. They had an average equivalent circle diameter ranging from 0.46-1.26 microm. MG63 cell response was assessed by measuring cell number, cellular and cell layer alkaline phosphatase, and prostaglandin E2 (PGE2) production. There were dose-dependent effects of the particles on cell response. Cell number and PGE, production were increased, while alkaline phosphatase specific activity was decreased. In addition, there was a marked difference between cultures treated with particles containing Ca-stearate and as a function of polymer molecular weight. Particles of higher molecular weight caused a greater stimulation of proliferation and inhibition of alkaline phosphatase than particles of lower molecular weight. The presence of Castearate exerted a more pronounced depression of osteoblast phenotype as well as a significantly greater increase in PGE2 release by the cells. The present study shows that chemical composition and polymer molecular weight of UHMWPE are capable of modulating osteoblast response to particles. The results suggest that osteoblast differentiation is inhibited by UHMWPE particles, whereas cell proliferation and PGE2 production are stimulated. This may have direct effects on osteoblasts and bone formation, but also paracrine effects on cells of the monocytic lineage inducing bone resorption and promoting inflammation which may lead to aseptic loosening. The present results suggest that the cellular events in aseptic loosening may be modulated or even accelerated by changes in the composition of the UHMWPE used to fabricate implants.

Alkaline Phosphatase↗
PubMed2004

Improvement of the functional properties of sucrose stearate by phosphorylation.

Phosphorylated sucrose stearate (SE-P) was prepared by dry-heating sucrose stearate (SE) with metaphosphoric acid. The main product was deduced to be a monophosphosucrose monostearate by chemical analysis and mass spectrometry. SE-P exhibited remarkably higher solubility and emulsifying properties than SE, especially in the acidic region and in the presence of NaCl, and SE-P bound Ca2+ at a 1:1 molar ratio (SE-P/Ca2+). SE-P markedly reduced the viscosity of potato starch paste and inhibited retrogradation, whereas SE did not reduce it so much. It is thus expected that phosphorylation would be an appropriate method for improving the functional properties of SE and that SE-P could be used as a novel emulsifier and modifier with Ca2+-binding ability for starchy foods.

Calcium↗
PubMed2005

Physicochemical characterization of PEG1500-12-acyloxy-stearate micelles and liquid crystalline phases.

PEG 12-acyloxy-stearates are used as drug delivery carriers that have low cell damage effects. The mechanical and physical properties surrounding these processes and surfactants are still however not known. In this study, the physicochemical micellar properties of PEG 12-acyloxy-stearates were characterized by optical microscopic, nuclear magnetic resonance, and small-angle X-ray scattering techniques. We determined the phase diagrams of the surfactants as a function of surfactant concentration and temperature, the micellar size and shape, and micellar dynamics. We found that each surfactant has a micellar, cubic Im3m, and hexagonal phase. The aggregation number in the discrete cubic phase, as determined by small-angle X-ray scattering, was approximately 150 for each surfactant, and showed no measurable chain-length dependence. The diffusion coefficients of the surfactant showed a discontinuity between the micellar and cubic phases, where the cubic phases gave very low values on the order of 10(-)(16) m(2) s(-)(1): this value indicates a non-bicontinuous cubic structure. In summary, these surfactants behave to a large extent as nonionic poly(ethylene glycol) surfactants with extended PEG headgroups.

Journal Article↗
PubMed1999

Improved stearate phenotype in transgenic canola expressing a modified acyl-acyl carrier protein thioesterase.

The engineering of crops for selected fatty acid production is one of the major goals of plant biotechnology. The Garm FatA1, an acyl-acyl carrier protein (ACP) thioesterase isolated from Garcinia mangostana, generates an elevated stearate (18:0) phenotype in transgenic Brassica plants. By site-directed mutagenesis, we generated seven mutants that showed up to a 13-fold increase in specific enzyme activity toward 18:0-ACP in vitro. The seed-specific expression of mutant S111A/V193A in Brassica plants results in transgenic plants that accumulate 55-68% more stearate than plants expressing the wild-type enzyme. Our results demonstrate that a thioesterase can be engineered to increase specific activity and that its improved function demonstrated in vitro is retained in vivo.

Amino Acid Sequence↗
PubMedDate not supplied

Release of albumin from oligoester plastic matrices: effect of magnesium oxide and bivalent stearates.

Biodegradable implantable matrices containing bovine serum albumin were prepared from oligoesters by melting, and subsequently tested on in vitro albumin release. The linear poly (DL-lactic acid) and the branched terpolymer of DL-lactic acid, glycolic acid, and mannitol were synthesized. Products were of similar molecular weight and possessed different thermal and swelling characteristics. Oligoesters were loaded with 4% albumin and plasticized by 30% triacetin. Other additives added into the matrices as albumin stabilizers were divalent stearates and magnesium oxide. The influences of oligomer molecules constitution, divalent ion stearates or magnesium oxide addition, and triacetin concentration on the albumin release were quantified. SDS-PAGE revealed protein hydrolysis during the dissolution tests.

Albumins↗
PubMed1985

Erythromycin stearate, 1.5 g, for the oral prophylaxis of streptococcal bacteraemia in patients undergoing dental extraction: efficacy and tolerance.

Erythromycin stearate, 1.5 g, was effective in reducing the prevalence of streptococcal bacteraemia following dental extraction when administered orally under supervision 1 h before extraction. Blood samples were collected from adult patients for culture and erythromycin assay 1 to 2 min after the dental procedure. High dilution techniques involving the use of 1 litre bottles of broth were used to inactivate erythromycin present in blood cultures. Viridans streptococci were isolated from 6 of 40 patients receiving erythromycin (15%) compared with 18 of 42 control patients (43%). The mean serum erythromycin concentration at the time of extraction was 3.7 mg/l for 34 patients receiving erythromycin who had negative blood cultures compared with 1.8 mg/l for the six patients given erythromycin who had viridans streptococci isolated from the blood. Both the 1.5 g erythromycin stearate and placebo oral doses were well tolerated in a double blind comparative study which included 109 adult dental patients.

Administration, Oral↗
PubMed1988

Time course of the antibacterial activity of erythromycin stearate and erythromycin acistrate against two Staphylococcus aureus strains in vitro.

The antibacterial efficacy of erythromycin stearate (ES) and a new erythromycin prodrug, erythromycin acistrate (EA, 2'-acetyl erythromycin stearate), was compared in two Staphylococcus aureus strains, one sensitive and the other resistant to erythromycin. The growth was continuously monitored turbidometrically for 24 h. With the sensitive S. aureus, the inhibitory effects of both ES and EA were visible within 1-2 h when the antibiotics were added at 0 or 1.5 h after the beginning of the incubation. When they were added at 3 h, their action was immediate at 0.5 and 1 mg/l, and 5 mg/l caused a complete inhibition of the growth. At 0.5 and 1 mg/l, however, ES was much more effective than EA. When EA and ES (1, 5 or 10 mg/l) were added at 0 or 1.5 h to the resistant staphylococcal culture, the lag phases (no detectable growth) were prolonged as a function of drug concentration but eventually the growth was restored. The action of EA was weaker and the lag phases were 2-5 h shorter than those after ES. When the compounds were added at 3 h, the antibacterial effect was visible immediately. The increase of absorbance was slowed down even by 1 mg/l of ES and almost prevented by 5 mg/l. At these concentrations EA was less effective than ES, but the two erythromycins were equally active at 10 mg/l. These results show that addition of EA acts on both staphylococci as rapidly as addition of ES but to a lesser extent. Evidently EA is antibacterially weaker than ES, or rapidly hydrolyzed to erythromycin after it has been added to the test system.

Drug Resistance, Microbial↗
PubMed2006

Reduction in cholesterol absorption is enhanced by stearate-enriched plant sterol esters in hamsters.

Consumption of plant sterol esters reduces plasma LDL cholesterol concentration by inhibiting intestinal cholesterol absorption. Commercially available plant sterol esters are prepared by esterifying free sterols to fatty acids from edible plant oils such as canola, soybean, and sunflower. To determine the influence of the fatty acid moiety on cholesterol metabolism, plant sterol esters were made with fatty acids from soybean oil (SO), beef tallow (BT), or purified stearic acid (SA) and fed to male hamsters for 4 wk. A control group fed no plant sterol esters was also included. Hamsters fed BT and SA had significantly lower cholesterol absorption and decreased concentrations of plasma non-HDL cholesterol and liver esterified cholesterol, and significantly greater fecal sterol excretion than SO and control hamsters. Cholesterol absorption was lowest in hamsters fed SA (7.5%), whereas it was 72.9% in control hamsters. Cholesterol absorption was correlated with fecal sterol excretion (r = -0.72, P < 0.001), liver cholesterol concentration (r = 0.88, P < 0.001), and plasma non-HDL cholesterol concentration (r = 0.85, P < 0.001). A multiple regression model that included each sterol ester type vs. cholesterol absorption indicated that intake of steryl stearate was the only dietary component that contributed significantly to the model (R2 = -0.75, P < 0.001). Therefore, our results demonstrate that BT and SA are more effective than SO in reducing cholesterol absorption, liver cholesterol, and plasma non-HDL cholesterol concentration, suggesting that cardioprotective benefits can be achieved by consuming stearate-enriched plant sterol esters.

Absorption↗
PubMedDate not supplied

Comparison of rosaramicin and erythromycin stearate for treatment of cervical infection with Chlamydia trachomatis.

The macrolide antibiotic rosaramicin inhibits in vitro growth of Chlamydia trachomatis. Rosaramicin (1 g daily given to 18 patients for seven days) and erythromycin stearate (2 g daily given to 19 patients for seven days) were compared in the treatment of chlamydial cervicitis. Cultures of cervical specimens obtained nine to 11 days and 24-32 days after commencement of therapy were negative for all rosaramicin-treated patients seen at follow-up. The first follow-up culture of one erythromycin recipient was positive. The extent of cervicitis decreased in all patients after treatment, but the only patients to achieve a completely normal cervical appearance were those with minimal-to-moderate lesions before treatment. Gastrointestinal side effects, including nausea, vomiting, and abdominal pain, occurred in ten of 19 patients given erythromycin and in 13 of 18 given rosaramicin. Minimally elevated levels of alanine aminotransferase in serum occurred in four (22.2%) of 18 rosaramicin recipients. It is concluded that rosaramicin and erythromycin stearate both eradicate C. trachomatis cervical infection but frequently cause adverse gastrointestinal effects.

Adolescent↗
PubMed1997

Palmitate and stearate binding to human serum albumin. Determination of relative binding constants.

Multiple binding equilibria of two apparently insoluble ligands, palmitate and stearate, to defatted human serum albumin were studied in a 66 mM sodium phosphate buffer (pH 7.4) at 37 degrees C, by determination of dialytic exchange rates of ligands among identical equilibrium solutions. The experimental data were analysed by a computerised curve fitting procedure using equilibrium equations for multiple binding of ligands, containing relative binding constants, valid whether the ligands are truly insoluble or are slightly soluble and irrespective of aggregation in aqueous solution. A best-fit set of relative binding constants was found, and subsequently 30 sets of acceptable constants for each set of data in order to evaluate the variation. The data were first fitted by the relative Scatchard's equation, then by the relative, stoichiometric equation. Scatchard's equation is deduced on the presumption that cooperativity is absent while the stoichiometric equation is valid even when cooperativity is present. It was found with palmitate as well as with stearate that the two equations fitted the data equally well, and it was concluded that the observations were compatible with absence of cooperativity. The relative Scatchard binding constants were converted to relative, stoichiometric constants and it was found that the variations of the latter were slight.

Humans↗
PubMed1976

Comparative pharmacology of josamycin and erythromycin stearate.

Two macrolide antibiotics, josamycin and erythromycin stearate, were administered orally to healthy, adult male volunteers for a comparative study of their pharmacological properties. In comparable doses, josamycin and erythromycin produced similar plasma concentrations, with similar half-lives and elimination constants. An initial loading dose of 1.5 g of josamycin produced greater peak concentrations of antibiotic throughout a 10-day period with a regimen of every 6 h. In addition, josamycin tended to reach higher peak and trough concentrations after regimens of every 6 or 8 h were maintained for 2 days. Josamycin penetrated into saliva, sweat, and tears, and it was better tolerated in fasting subjects than was erythromycin stearate.

Adult↗
PubMed1981

Influence of study design in assessing food effects on absorption of erythromycin base and erythromycin stearate.

We performed a series of six single-dose and multiple-dose studies to evaluate the effect of food on the absorption of erythromycin base and erythromycin stearate. When we used a single-dose design, we found that an unprotected erythromycin base preparation was absorbed extensively if a prolonged fast preceded administration of the drug. A shorter faster period (as occurs in clinical settings) dramatically reduced the absorption of unprotected base; however, film-coated tablets seemed to be as well protected as and were absorbed more rapidly than enteric-coated tablets when they were evaluated by single-dose testing procedures. In contrast, when a commercially available film-coated preparation of erythromycin base was evaluated in multidose fashion between meals (fasting), the drug was about 25% less well absorbed than commercially available enteric-coated base tablets. Finally, when commercially available film-coated erythromycin base and stearate formulations were administered with meals, both film-coated preparations were 43 to 59% less well absorbed than the enteric-coated base formulation. Furthermore, the enteric-coated base formulation performed equally well when administered either every 6 h between meals (fasting) or four times a day (immediately after meals and at bedtime). These studies document the need for multidose bioavailability techniques when the bioavailabilities of acid-labile drugs are evaluated.

Adult↗
PubMed1984

Erythromycin stearate in treating chlamydial infection of the cervix.

A total of 157 women attending departments of genitourinary medicine were treated for chlamydial infection of the cervix with erythromycin stearate 500 mg twice a day. Chlamydiae were eradicated from the cervix in 64/80 women treated for seven days and in 51/77 women treated for 14 days. In 12 of those treated for seven days and 15 of those treated for 14 days, reinfection was the probable cause of reisolation after treatment. The possibility of latent infection with Chlamydia trachomatis could not be excluded in five women, but was not more likely to occur with the shorter treatment course. Erythromycin stearate 500 mg twice daily for seven days appears to be an effective regimen for the treatment of uncomplicated chlamydial infection of the cervix.

Chlamydia Infections↗
PubMed1981

Effect of systemic erythromycin stearate on the inflammatory lesions and skin surface fatty acids in acne vulgaris.

In a 6-week and double-blind study the efficacy of systemic administered erythromycin stearate and doxycycline was compared in 56 patients with facial acne vulgaris. With both antibiotics a statistically significant improvement was demonstrated without any difference between the two groups. No patient had to withdraw therapy due to side-effects. Another part of this investigation correlates the degree of inflammation in acne vulgaris with the fatty acid level in human skin surface lipids before and after systemic erythromycin stearate therapy. This antibiotic reduced the amount of fatty acids 25--50% after a month of medication. The reduction was correlated with a definite clinical improvement in 14 of the 17 patients.

Acne Vulgaris↗
PubMed1978

Erythromycin stearate in acne vulgaris: its effect on the skin surface lipids and on the activity of purified pancreatic lipase.

To study the mechanism of action of erythromycin stearate in acne vulgaris, the composition of the skin surface lipids was analyzed before, during and after treatment (500 mg daily for 1 week, 250 mg daily for 2 months) in 17 patients. Quantitative thin-layer chromatography showed that the fatty acid fraction in the skin surface lipids decreased significantly during the treatment period. The clinical effect was good in 14 of 17 patients. Further investigations were performed on the effect of erythromycin stearate on purified pancreatic lipase. The enzyme activity was not inhibited by exposure to the drug.

Acne Vulgaris↗