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The aim of this study was to determine whether a tooth cream containing casein/calcium phosphate (CasCP) protects enamel against erosion. Sixty bovine enamel specimens were prepared for profilometry and distributed into five groups. Specimens were rinsed with artificial saliva interrupted by 1% citric acid (pH 2.3) for 30 s 6 times daily for 14 days. Group 1 (n = 12) was not treated (control); in group 2 (n = 12) CasCP was applied for 120 s twice daily; in group 3 (n = 12) 250 ppm fluoride as NaF was applied for 120 s twice daily; in group 4 (n = 12) CasCP was applied for 120 s, then 250 ppm fluoride for 120 s twice daily, and in group 5 (n = 12) amine fluoride (AmF) gel (12,500 ppm fluoride) was applied for 120 s twice daily. Differences between groups with respect to erosive enamel loss (profilometrically determined depth after 7 and 14 days) were tested by the Mann-Whitney test (α = 0.05). After 7/14 days’ erosive cycling, specimens treated with AmF gel showed significantly less enamel loss (18.5/35.5 µm; medians) than those treated with CasCP (25.5/46.9 µm), 250 ppm fluoride (25.0/ 40.9 µm), CasCP and 250 ppm fluoride (23.9/47.4 µm) or with no treatment (26.3/49.8 µm). It is concluded that highly fluoridated acidic AmF gel can protect enamel against erosion while CasCP, 250 ppm fluoride or a combination of CasCP and 250 ppm fluoride provide little protection.

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The caecal microflora of Cara rats was incubated in the pH stat with glucose under anaerobic conditions, and the acid production was measured. In the presence of the sweeteners Acesulfame K, Cyclamate and Saccharin, inhibition of the fermentation of glucose was observed with ED50 values of 260, 251, and 140 mM, respectively. The nutritional relevance of these observations is probably slight; an interpretation in terms of bacterial physiology leads to the proposal that the sweeteners may act on glucose transport systems at the bacterial cytomembrane.

At equivalent oral doses, cefadroxil has a longer serum half-life, slower urinary excretion rate, greater area under the serum level versus time curve than cephalexin or cephradine, and peak serum concentrations that are 75 to 80% those of cephalexin. The calculated, apparent in vivo volume of distribution of cefadroxil is greater than that of cephalexin. These properties infer greater persistence of cefadroxil in serum and urine and more prolonged in vivo bacterial exposure to cefadroxil than to cephalexin or cephradine. Neither cefadroxil nor cephalexin demonstrates drug accumulation on repeated administration. The serum levels achieved by cefadroxil are unaffected by food. The pharmacokinetic properties of cefadroxil are supportive of the development of clinical efficacy data which could indicate that cefadroxil could be administered at 12-h intervals.The studies reported here were undertaken to compare the pharmacokinetic properties in humans of the orally administered cephalosporin antibiotics cefadroxil, cephalexin, and cephradine (structures presented in Fig. 1) and to determine the factors which control their disposition in vivo. A companion paper presents data on the antibacterial activity of cefadroxil (1). The inhibitory activity of cefadroxil on clinical isolates was similar to that of cephalexin and cephradine. Cefadroxil was more effective than cephalexin against Streptococcus pyogenes and comparably as effective as cephalexin against Streptococcus pneumoniae, Staphylococcus aureus, and several gram-negative species in oral treatment of experimental infections in mice. MATERIALS AND METHODSBioassays for antibiotic activity in serum and urine were carried out by standard cup plate assay methodology (4) blood area nitrogen, serum glutamic pyruvic transaminase, bilirubin, urinalysis (including protein test, sugar and microscopy for casts and cells), and stool parasitological examination. Subjects with abnormal values or findings were not admitted into these studies. None of the subjects were to have taken any medication for 3 weeks prior to the study in which they participated.All subjects were fasted overnight before each study. Oral doses of drugs were always administered at 8:00 a.m. with 250 ml of water, and a further 250 ml of water was ingested every succeeding 2 h for the duration of the study. Except for portions of a study on the effect of food on drug bioavailability, the subjects maintained their fast for 2 h after drug administration.All studies were designed as balanced, randomized complete crossovers. There was a 6-day washout period between crossover legs.Study

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The pharmacokinetics of cefepime were studied in 10 male patients receiving continuous ambulatory peritoneal dialysis therapy. Five patients received a single 1,000-mg dose and the other five received a single 2,000-mg dose; all doses were given as 30-min intravenous infusions. Serial plasma, urine, and peritoneal dialysate samples were collected; and the concentrations of cefepime in these fluids were measured over 72 h by using a high-performance liquid chromatographic assay with UV detection. Pharmacokinetic parameters were calculated by noncompartmental methods. The peak concentrations in plasma and the areas under the plasma concentration-versus-time curve for the 2,000-mg dose group were twice as high as those observed for the 1,000-mg dose group. The elimination half-life of cefepime was about 18 h and was independent of the dose. The steady-state volume of distribution was about 22 liters, and values for the 1,000-and 2,000-mg doses were not significantly different. The values for total body clearance and peritoneal dialysis clearance were about 15 and 4 ml/min, respectively. No dose dependency was observed for the clearance estimates. Over the 72-h sampling period, about 26% of the dose was excreted intact into the peritoneal dialysis fluid. For 48 h postdose, mean concentrations of cefepime in dialysate at the end of each dialysis interval exceeded the reported MICs for 90%o of bacteria which commonly cause peritonitis resulting from continuous peritoneal dialysis. A