Pharmacokinetics of cefprozil in healthy subjects and patients with hepatic impairment

Population Pharmacokinetics of Cis-, Trans-, and Total Cefprozil in Healthy Male Koreans

Cefprozil, one of cephalosporin antibiotics, has been used extensively in clinics. However, pharmacokinetic (PK) information on cefprozil is still very limited. There have been no reports of population pharmacokinetics (PPKs). A PPK model for cefprozil will be a great advantage for clinical use. Thus, the aim of this study was to develop a PPK model for cefprozil for healthy male Koreans. Clinical PK and demographic data of healthy Korean males receiving cefprozil at a dose of 1000 mg were analyzed using Phoenix^® NLME™. A one-compartment model with first-order absorption with lag-time was constructed as a base model. The model was extended to include covariates that influenced between-subject variability. Creatinine clearance significantly influenced systemic clearance of cefprozil. The final PPK model for cis-, trans-, and total cefprozil was established and validated. PPK parameter values of cis- and total cefprozil were similar to each other, but different from those of trans-isomer. Herein, we describe the establishment of accurate PPK models of cis-, trans-, and total cefprozil for healthy male Koreans for the first time. It may be useful as a dosing algorithm for the general population. These results might also contribute to the development of stereoisomeric cefprozil.

An LC-MS/MS method for simultaneous determination of cefprozil diastereomers in human plasma and its application for the bioequivalence study of two cefprozil tablets in healthy Chinese volunteers

A rapid and sensitive liquid chromatography-tandem mass spectrometric method was developed for the first time and validated for the determination of cefprozil diastereomers in human plasma. The plasma samples were prepared by protein precipitation using acetonitrile. Detection was performed using an electronic spray ion source in the negative ion mode, operating in the multiple reaction monitoring of the transitions m/z 388.0 to m/z 205.0 for cefprozil diastereomers and m/z 346.1 to m/z 268.1 for cephalexin (the internal standard). The calibration curves of cis-cefprozil and trans-cefprozil were linear in the ranges 0.125-16.0 µg/mL and 0.0403-1.72 µg/mL, respectively. The lower limits of quantification of cis- and trans-cefprozil were 0.125 and 0.0403 µg/mL in human plasma, respectively. The intra- and inter-day precisions of cis- and trans-cefprozil were all <9.7%, and the accuracy ranged from 99.2 to 104.7% and from 100.6 to 102.2%, respectively. The validated method was successfully applied to a bioequivalence study of two cefprozil formulations in 24 healthy Chinese volunteers. The two cefprozil tablets were bioequivalent by measurement of cis-, trans- and total cefprozil. We suggest that the bioequivalence of cefprozil formulations can be evaluated only using cis-cefprozil as the analyte in future studies.

A rare case of hepatitis associated with cefprozil therapy

Cefprozil is a novel third generation, broad-spectrum oral cephalosporin. Serum sickness-like reaction and rash caused by cefprozil have been previously reported, but liver damage has not been documented. We report on a 15 years-old female with tonsillopharyngitis who developed hepatitis after treatment with cefprozil. Following discontinuation of cefprozil therapy, her liver functions returned to normal limits within four weeks. We suggest that for patients presenting with hepatitis associated with drugs, Cefprozil should be considered in the differential diagnosis of hepatitis.

Dose adjustment in patients with liver disease

Unfortunately, there is no endogenous marker for hepatic clearance that can be used as a guide for drug dosing. In order to predict the kinetic behaviour of drugs in cirrhotic patients, agents can be grouped according to their extent of hepatic extraction. For drugs with a high hepatic extraction (low bioavailability in healthy subjects), bioavailability increases and hepatic clearance decreases in cirrhotic patients. If such drugs are administered orally to cirrhotic patients, their initial dose has to be reduced according to hepatic extraction. Furthermore, their maintenance dose has to be adapted irrespective of the route of administration, if possible, according to kinetic studies in cirrhotic patients. For drugs with a low hepatic extraction, bioavailability is not affected by liver disease, but hepatic clearance may be affected. For such drugs, only the maintenance dose has to be reduced, according to the estimated decrease in hepatic drug metabolism. For drugs with an intermediate hepatic extraction, initial oral doses should be chosen in the low range of normal in cirrhotic patients and maintenance doses should be reduced as for high extraction drugs. In cholestatic patients, the clearance of drugs with predominant biliary elimination may be impaired. Guidelines for dose reduction in cholestasis exist for many antineoplastic drugs, but are mostly lacking for other drugs with biliary elimination. Dose adaptation of such drugs in cholestatic patients is, therefore, difficult and has to be performed according to pharmacological effect and/or toxicity. Importantly, the dose of drugs with predominant renal elimination may also have to be adapted in patients with liver disease. Cirrhotic patients often have impaired renal function, despite a normal serum creatinine level. In cirrhotic patients, creatinine clearance should, therefore, be measured or estimated to gain a guideline for the dosing of drugs with predominant renal elimination. Since the creatinine clearance tends to overestimate glomerular filtration in cirrhotic patients, the dose of a given drug may still be too high after adaptation to creatinine clearance. Therefore, the clinical monitoring of pharmacological effects and toxicity of such drugs is important. Besides the mentioned kinetic changes, the dynamics of some drugs is also altered in cirrhotic patients. Examples include opiates, benzodiazepines, NSAIDs and diuretics. Such drugs may exhibit unusual adverse effects that clinicians should be aware of for their safe use. However, it is important to realise that the recommendations for dose adaptation remain general and cannot replace accurate clinical monitoring of patients with liver disease treated with critical drugs.

Cefprozil: a review

Cefprozil is a novel third generation, broad-spectrum oral cephalosporin with activity against a spectrum of aerobic gram-negative and positive bacteria, as well as certain anaerobes. The beta-lactamase stability of cefprozil may exceed that of other oral cephalosporins for some important pathogens. Cefprozil may be a suitable alternative to several other commonly used beta-lactams and cephalosporins in the treatment of mild to moderate upper and lower respiratory tract infections including sinusitis, otitis media, pharyngitis/tonsillitis, secondary bacterial infection of acute bronchitis, and acute bacterial exacerbations of chronic bronchitis, and skin and skin structure infections in children. Available data indicate the safety of cefprozil in both pediatric and adult population.

Comparative microbiological activity and pharmacokinetics of cefprozil

In vitro studies on the activity of cefprozil have been conducted in Europe and North America. Against gram-negative bacilli, cefprozil and cefaclor are at least two to four times more active than cephalexin. Cefixime is more active against these organisms. Against gram-positive cocci, cefprozil is at least two to four times more active than cefaclor and cephalexin; cefixime has limited gram-positive activity, and is particularly inactive against staphylococci (MIC90 32 mg/l). Cefprozil is highly active against Streptococcus pneumoniae (unlike cefixime). Those strains of this genus that display intermediate resistance to pneumococci are more susceptible to cefprozil than cefaclor. Neisseria species and Moraxella catarrhalis are susceptible to cefprozil (MIC90 0.06 and 1 mg/l). beta-lactamase-producing strains of Haemophilus influenzae appear to be susceptible to cefprozil, as the reported MIC90 is 2-4 mg/l. Enterococci, Pseudomonas aeruginosa, and those strains of the Enterobacteriaceae that commonly possess a chromosomal cephalosporinase (e.g., Providencia, Morganella and Enterobacter) are generally considered to be resistant to cefprozil as well as to other oral cephalosporins. Cefprozil appears to display enhanced stability to the commonly encountered Tem-1 and SHV-1 plasmid-mediated beta-lactamases, as found in Haemophilus influenzae, Neisseria gonorrhoeae and the Enterobacteriaceae. Cefprozil is rapidly absorbed, reaching a maximum concentration 0.9 to 1.2 h post-dose. Following oral doses of 250 and 500 mg, the Cmax is 6.2 and 10.0 mg/l respectively. Serum half-lives are generally reported as between 1.2 and 1.4 h, and urine recovery is high, 57-70%.(ABSTRACT TRUNCATED AT 250 WORDS)

Review of in vitro activity, pharmacokinetic characteristics, safety, and clinical efficacy of cefprozil, a new oral cephalosporin

OBJECTIVE

To review the pharmacokinetics, microbiology, clinical efficacy, safety, and tolerance of cefprozil, a new, broad-spectrum oral cephalosporin.

DATA SOURCES

Published clinical trials and microbiologic, pharmacokinetic, and safety data were identified by MEDLINE; additional references were derived from bibliographies of these articles; microbiologic data on file were provided by Bristol-Myers Squibb.

STUDY SELECTION

Only published comparative clinical trial reports are included in the review of clinical efficacy. Noncomparative clinical data pertaining to uses of cefprozil not approved by the Food and Drug Administration are not included.

DATA SYNTHESIS

Data are presented on the in vitro microbiologic activity of cefprozil against 10,152 bacterial isolates, including most of the clinically important streptococci (e.g., Streptococcus pyogenes, Streptococcus pneumoniae), beta-lactamase-positive and -negative Staphylococcus aureus and Haemophilus influenzae, Moraxella catarrhalis, Escherichia coli, Proteus mirabilis, Clostridium difficile, and numerous other gram-negative aerobes and anaerobes. In clinical trials, cefprozil appears to be at least as effective as commonly used comparison agents such as cefaclor, cefixime, and amoxicillin/clavulanic acid. Additionally, cefprozil is better tolerated than the latter two agents, especially with regard to gastrointestinal adverse effects.

CONCLUSIONS

Cefprozil is a broad-spectrum cephalosporin that provides coverage against both gram-negative and -positive bacteria that may cause otitis media, pharyngitis/tonsillitis, skin and skin-structure infections, secondary bacterial infection of acute bronchitis, and acute bacterial exacerbations of chronic bronchitis. The beta-lactamase stability of cefprozil appears to exceed that of other oral cephalosporins for some important pathogens. Cefprozil is used primarily for second-line treatment as less-expensive, first-line generic alternatives generally are available. Cefprozil demonstrates clinical advantages over many other orally administered beta-lactam antibiotics in terms of antimicrobial spectrum, a once- or twice-daily dosing regimen, and/or reduced incidence of adverse effects.

Cefprozil

Cefprozil is a new, orally bioavailable, cephalosporin with significant activity against the bacteria commonly associated with upper and lower respiratory tract infection, and skin and soft tissue infections. Its absorption and elimination dynamics suggest once- or twice-daily dosing. The low-rate of gastrointestinal and dermatologic side effects associated with cefprozil administration suggest that it may have a significant role in the management of patients with these infections. Children with pharyngitis or urinary tract infection are more appropriately treated with antibiotics having a narrower spectrum of activity. With a variety of newer cephalosporins being marketed in the early 1990s, it will be important for the clinician to examine the data from ongoing comparative clinical trials to determine which antibiotic is best for a patient with a specific infection and whether the added cost justifies its use.

Oral absolute bioavailability and intravenous dose-proportionality of cefprozil in humans

The absolute bioavailability (F) and dose proportionality of cefprozil were investigated in a parallel design study with an embedded two-way crossover leg. Twenty-four healthy male subjects divided into 3 dosing groups received a single 250-, 500-, or 1000-mg dose of cefprozil by a 30-minute intravenous infusion. Subjects assigned to the 500-mg dose group also received a 500-mg oral dose of cefprozil in crossover manner with a wash-out period of 7 days between each treatment. Cefprozil consists of cis and trans isomers in an approximate 90:10 ratio. Serial blood and urine samples were collected and analyzed for the concentrations of the cis and trans isomers of the cephalosporin using high-pressure liquid chromatographic assay with UV detection methods. After the 250-, 500-, and 1000-mg intravenous administration of cefprozil, the peak concentrations were 13.2, 26.0, and 48.5 micrograms/mL, and area under the plasma concentration versus time profiles were 17.2, 31.4, and 58.1 micrograms.hour/mL, respectively, for the cis isomer increasing in a dose proportional manner. Total body clearance, renal clearance, and volume of distribution at steady state, adjusted for body weight, were not significantly different among all groups. Mean residence time, elimination half-life, and urinary recovery were invariant with the dose. Based on the plasma and urine data, the estimates of F were 89% and 94% for the cis isomer, respectively. The plasma concentrations of the trans isomer were about 1/10th of the cis isomer, and all parameters were similar to those observed for the cis isomer. In summary, cefprozil exhibits linear pharmacokinetics and is essentially completely absorbed after oral administration.

Pharmacokinetic interactions of cefprozil with food, propantheline, metoclopramide, and probenecid in healthy volunteers

Cefprozil, a new oral cephalosporin antibiotic, is composed of cis and trans isomers in an approximate 90:10 ratio. The objectives of this study were: (1) to assess the effects of alterations in gastrointestinal motility by metoclopramide and propantheline on the pharmacokinetics of cis and trans isomers of cefprozil, and to compare them with the effects of food on the pharmacokinetics of cefprozil; (2) to assess the effects of inhibition of renal tubular secretion by probenecid on the pharmacokinetics of cefprozil isomers. In this four-way crossover study, 15 healthy male volunteers received a 1000-mg dose of cefprozil after fasting, pretreatment with metoclopramide or propantheline, after breakfast, or after probenecid in an incomplete, balanced block design. There was a 1-week washout period between each treatment. Blood and urine samples collected over a 24-hour period were assayed for the cis and trans isomers. The concentrations of the trans isomers were generally 1/10 of the cis isomer. The means and variances of the pharmacokinetic parameters of the cis and trans isomers of cefprozil were similar in fasting subjects and were affected in a parallel manner by food, metoclopramide, propantheline, and probenecid. The pharmacokinetics of the cis isomer under the fasting condition were as follows: maximum peak plasma concentration (Cmax), 14.0 +/- 2.7 micrograms/mL; median time to reach Cmax (tmax), 1.5 (range, 1.0-3.5) hours; half-life (t1/2), 1.24 +/- 0.27 hours; area under the concentration (AUC0-infinity), 47.3 +/- 7.7 micrograms.hour/mL; mean residence time after oral administration (MRTpo), 2.9 +/- 0.4 hours; CLR, 219 +/- 60 mL/minute; and Xu% (percent cumulative urinary excretion in 0-24 hours), 68.1 +/- 12.5.(ABSTRACT TRUNCATED AT 250 WORDS)

Effect of antacid on the bioavailability of cefprozil

The effect of antacid on the bioavailability of cefprozil was investigated in a two-way crossover study. Eight healthy male subjects received a single 500-mg oral dose of cefprozil with and without coadministration of 30 ml of an antacid suspension containing magnesium hydroxide and aluminum hydroxide (Maalox). Cefprozil consists of cis and trans isomers in an approximate 90:10 ratio. When cefprozil was administered alone (treatment A), the mean maximum concentrations (Cmax) of the cis and trans isomers were 9.2 and 1.2 micrograms/ml, respectively. When cefprozil was coadministered with Maalox (treatment B), the Cmax values of the cis and trans isomers were 8.7 and 1.3 micrograms/ml, respectively. The mean values of the area under the curve from time zero to infinity (AUC0-infinity) were 27.7 and 3.5 micrograms.h/ml for treatment A and 27.5 and 3.5 micrograms.h/ml for treatment B for the cis and trans isomers, respectively. The other pharmacokinetic parameters, time to Cmax, elimination half-life, mean residence time, renal clearance, and percent urinary excretion, were essentially the same for the two isomers. The respective values of the elimination half-life for the cis and trans isomers were 1.36 and 1.32 h for treatment A and 1.36 and 1.42 h for treatment B. Mean urinary excretion was 63 and 60% for treatment A and 58 and 56% for treatment B for the cis and trans isomers, respectively. No significant differences between the two treatments were found for any of the pharmacokinetic parameters for either isomer. For the cis isomer, bioavailability point estimates (90% confidence intervals) of the mean Cmax and AUG0-infinity values for the Maalox treatment relative to those for the reference treatment were 95% (87%, 103%) and 99% (95%, 104%), respectively. For the trans isomer, the value were 109% (92%, 126%) for Cmax and 97% (88%, 106%) for AUC0-infinity. On the basis of the results of this study, it is concluded that the bioavailability of cefprozil is not affected by the coadministration of Maalox.

Excretion of cefprozil into human breast milk

The excretion of cefprozil into breast milk in nine healthy, lactating female subjects was investigated. Each subject received a single 1,000-mg oral dose of cefprozil consisting of cis and trans isomers in an approximately 90:10 ratio. Serial blood, urine, and breast milk samples were collected and analyzed for the concentrations of the cis and trans isomers by a specific high-pressure liquid chromatography-UV assay. The mean pharmacokinetic parameters for both isomers were essentially the same. The mean peak concentrations in plasma for the cis isomer were 14.8 micrograms/ml, and the area under the concentration curve was 54.8 micrograms.h/ml. The mean values of elimination half-life, renal clearance, and urinary excretion for the cis isomer were 1.69 h, 164 ml/min, and 60%, respectively. The mean concentrations in milk of the cis isomer over a 24-h period ranged from 0.25 to 3.36 micrograms/ml, with the maximum concentration appearing at 6 h after dosing. The average maximum concentration in milk of the trans isomer was less than 0.26 micrograms/ml. The concentrations of the trans isomer in plasma and in breast milk were about 1/10 of those for the cis isomer. Less than 0.3% of the dose was excreted in breast milk for both isomers of cefprozil. Even if one assumes that the concentration of cefprozil in milk remains constant at 3.36 micrograms/ml (the highest concentration of cefprozil observed in breast milk), an infant ingesting an average of 800 ml of milk per day will be exposed to a maximum amount of about 3 mg of cefprozil per day. This value represents about 0.3% of the maternal dose. Low excretion of cefprozil in breast milk and the excellent safety profile of cefprozil suggest that this cephalosporin may be administered to nursing mothers when indicated.