• Korean Journal of Veterinary Research
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• v.50 no.1
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• pp.11-17
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• 2010

Linear and non-linear regressions were used to derive the calibration function for the measurement of roxithromycin plasma concentration. Their results were compared with weighted least squares regression by usual weight factors. In this paper the performance of a non-linear calibration equation with the capacity to account empirically for the curvature, y = ax$^{b}$ + c (b $\neq$ 1) is compared with the commonly used linear equation, y = ax + b, as well as the quadratic equation, y = ax$^{2}$+ bx + c. In the calibration curve (range of 0.01 to 10 ${\mu}g/mL$) of roxithromycin, both heteroscedasticity and nonlinearity were present therefore linear least squares regression methods could result in large errors in the determination of roxithromycin concentration. By the non-linear and weighted least squares regression, the accuracy of the analytical method was improved at the lower end of the calibration curve. This study suggests that the non-linear calibration equation should be considered when a curve is required to be fitted to low dose calibration data which exhibit slight curvature.

• Tuberculosis and Respiratory Diseases
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• v.45 no.3
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• pp.546-552
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• 1998

Background: Up to 90% of a theophylline dose is biotransformed, by interaction with one or more the variants of the cytochrome P-450 drug metabolism system. Macrolides affect the elimination of theophylline by influencing on the microsomal enzyme systems. We evaluate the effect of erythromycin and new macrolides on the serum theophylline level and clearance. Method : Subjects consisted of moderate asthmatic patients with normal renal and hepatic functions. All subjects were non-smokers and treated with oral theophylline 400 mg per day. We randomly assigned 53 patients into four groups. Each group was treated with one macrolides, the first group erythromycin(n:19, 500 mg bid), second roxithromycin (n:14. 150 mg bid), third clarithromycin (n:10, 250 mg bid) and fourth azithromycin(n:10, 250 mg bid). We measured the serum theophylline level and clearance at three intervals, at pretreatment, after the first and fourth week after receiving the following macrolides, erythromycin, roxithromycin and clarithromycin. When azithromycin was administered, the serum theophylline level was measured at pretreatment and after one week of treatment They were measured by a computerized program of Bayesian method. Results : When compared with control, erythromycin and roxithromycin-treated groups had a significantly elevated serum theophylline level and decreased clearance. However, there were no significant changes of the serum theophylline level and clearance in clarithromycin and azithromycin-treated groups. Conclusion : These results suggest that theophylline dose may need to be readjusted and have periodic drug monitoring when erythromycin or roxithromycin is administered concurrently.

• Journal of Veterinary Clinics
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• v.23 no.2
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• pp.87-90
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• 2006

The aim of the present study was to investigate the disposition pharmacokinetics of roxithromycin in broilers. Roxithromycin was administered at a single dose of 20 mg/kg body weight by intravenous (i.v.) routes. Plasma concentrations of roxithromycin were determined by liquid chromatography/mass spectrometry. After a single i.v. dose plasma concentrations were best fitted to a two-compartment open model. The values of the pharmacokinetic parameters after i.v. administration were: elimination half-life = $5.83{\pm}1.79h$, mean residence time = $6.33{\pm}0.32h$, total body clearance = $0.55{\pm}0.15L/h/kg$, and volume of distribution at steady state = $3.47{\pm}0.84L/kg$. The pharmacokinetic interpretation of roxithromycin after i.v. administration revealed that the drug was well distributed throughout the body in broilers and slowly eliminated. More studies for the application of roxithromycin against poultry disease are needed to establish a suitable pharmaceutical formulation, propose optimum dosage regimens, investigate clinical efficacy and study the tolerability of repeated doses.

• Archives of Pharmacal Research
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• v.23 no.5
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• pp.507-512
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• 2000

This study set out to improve the physical and pharmaceutical characteristics of the present formulation using an appropriate experimental design. The work described here concerns the formulation of the dispersible tablet applying direct compression method containing roxithromycin in the form of coated granules. In this study $2^3$ factorial design was used as screening test model and Central Composite Design (CCC) associated with response surface methodology was used as optimization study model to develop and to optimize the proper formulation of roxithromycin dispersible tablet. The three independent variables investigated were functional excipients like binder (X1), disintegrant (X2) and lubricant (X3). The effects of these variables were investigated on the following responses: hardness (Y1), friability (Y2) and disintegration time (Y3) of tablet. Three replicates at the center levels of the each design were used to independently calculate the experimental error and to detect any curvature in the response surface. This enabled the best formulations to be selected objectively. The effect order of each term to all response variable was X3> X2> Xl> X1＊X2> X2＊X2> X2＊X3> X3＊X3> Xl＊X3> Xl＊Xl and model equations on each response variables were generated. Optimized compositions of formula were accordingly computed using those model equations and confirmed by following demonstration study. As a result, this study has demonstrated the efficiency and effectiveness of using a systematic formulation optimization process to develop the tablet formulation of roxithromycin dispersible tablet with limited experiment.

• Journal of Veterinary Clinics
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• v.24 no.1
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• pp.5-9
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• 2007

The purpose of this study was to examine the allometric analysis of roxithromycin using pharmacokinetic data. The pharmacokinetic parameters used were $half-life(t_{1/2})$, mean residence time (MRT), clearance (Cl) and volume of distribution at steady state $(V_{ss})$. Relationships between body weight and the pharmacokinetic parameter were based on the empirical formula $Y=aW^b$, where 'Y' is $t_{1/2}$, MRT, Cl, or $V_{ss}$, W the body weight and 'a' is an allometric coefficient (intercept) that is constant for a given drug. The exponential term, 'b', is a proportionality constant that describes the relationship between the pharmacokinetic parameter of interest and body weight. As results of the allometric analyses, the logarithms of $t_{1/2}$, MRT, Cl, and $V_{ss}$ were linearly related to the logarithms of body weight. Results of the current analyses could provide information on appropriate doses of roxithromycin for all species.

• Analytical Science and Technology
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• v.30 no.1
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• pp.39-48
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• 2017

Roxithromycin (RXT), which is an antibiotic used to treat respiratory tract and urinary infections, is official in Korean Pharmacopoeia (KP) and is marketed in various dosage forms including tablet, granule, suspension, and tablet for suspension in Korea. This study presents how a universal and reliable method to quantify RXT in bulk drug and formulations was developed. Effects of factors including column type, buffer concentration, type and concentration of organic solvent, buffer pH, and type and concentration of mobile phase additive, were examined, and some categorical or crucial factors including the types of column, organic solvent, mobile phase additive and the buffer pH were optimized by one-factor-at-a-time approach. Subsequently, concentrations of the buffer and additive and column temperature were optimized by response surface methodology using Box-Behnken design aiming to acquire the RXT peak of good shape. The optimized method employed a Phenomenex Gemini $5{\mu}$ C18 110A ($150{\times}4.60mm$, $5{\mu}m$) maintained at $30^{\circ}C$ with the mobile phase consisting of 25 mM phosphate buffer (pH 6.0) with 0.3 % tetrabutylammonium hydroxide and methanol at a ratio of 37:63 (v/v). Method validation results showed that the developed method was linear, precise, and accurate. Compared to the compendial methods in KP 10 that exhibited a significant tailing of the RXT peak despite using unfavorably high buffer concentrations and were not harmonized among bulk drug and formulations, this method could be universally applied to RXT bulk drug and marketed products in various dosage forms and thus was adopted in KP 11.

• Journal of Pharmaceutical Investigation
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• v.34 no.3
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• pp.209-214
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• 2004

A bioequivalence study of $Roxithrin^{TM}$ tablet (Kukje Pharma. Ind. Co., Ltd.) to $Rulid^{TM}$ tablet (Han Dok Pharma. Ind. Co., Ltd.) was conducted according to the guidelines of Korea Food and Drug Administration (KFDA). Twenty four healthy male Korean volunteers received each medicine at the roxithromycin dose of 300 mg in a $2{\times}2$ crossover study. There was a one-week wash-out period between the doses. Plasma concentrations of roxithromycin were monitored by a high-performance liquid chromatography for over a period of 36 hours after drug administration. $AUC_t$ (the area under the plasma concentration-time curve from time zero to 36 hr) was calculated by the linear trapezoidal rule method. $C_{max}$ (maximum plasma drug concentration) and $T_{max}$ (time to reach $C_{max}$) were compiled from the plasma concentration-time data. Analysis of variance was carried out using logarithmically transformed $AUC_t$ and $C_{max}$. No significant sequence effect was found for all of the bioavailability parameters indicating that the cross-over design was properly performed. The 90% confidence intervals of the $AUC_t$ ratio and the $C_{max}$ ratio for $Roxithrin^{TM}/Rulid^{TM}$ were 1.00 - 1.13 and 0.98 - 1.10, respectively. These values were within the acceptable bioequivalence intervals of 0.80 - 1.25. Thus, our study demonstrated the bioequivalence of $Roxithrin^{TM}$ and $Rulid^{TM}$ with respect to the rate and extent of absorption.

• Clinical and Experimental Pediatrics
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• v.46 no.7
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• pp.710-713
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• 2003

Purpose : Although chloramphenicol and doxycycline have been used for the treatment of tsutsugamuchi disease, a difficulty exists in determining which drugs to use in treating children because of potential complications such as aplastic anemia or teeth discoloration. We evaluated the effect of roxithromycin, a macrolide antibiotic, on tsutsugamushi disease in children. Methods : A retrospective analysis was conducted on 39 children with tsutsugamuchi disease(scrub typhus) who were treated with doxycycline(DC), chloramphenicol(CM), or roxythromycin(RM) between 1991 and 2000. We divided the patients into a DC-treated group(DC group; 16 children), a CM-treated group(CM group; 14 children), and RM-treated group(RM group; 9 children) and compared these groups. Results : Most cases(97%) developed in October and November. Fever and rash were observed in all 39 cases and an eschar was noted in 36 cases(92%). No statistical differences could be found between the three groups in mean age, duration of fever before admission, white blood cell(WBC) count, and complications including abnormal liver enzymes. In most cases defervescence after treatment was within 24 hours(34 cases, 87%), and during 24-48 hours in two cases in the DC group, one in the CM group, and two in the RM group(no statistical difference). Conclusion : Roxythromycin was as effective as conventional doxycycline or chloramphenicol, in children with scrub typhus and may be safer to use.

• Biomolecules & Therapeutics
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• v.14 no.1
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• pp.50-55
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• 2006

The objective of the study was to evaluate the bioequivalency between the $Rozid^{TM}$ Tablet (Ilhwa Pharm. Co., Ltd.) as a test formulation and the $Rulid^{TM}$ Tablet (Handok Pharm. Co., Ltd) as a reference formulation. Twenty-four healthy male volunteers were administered the formulations by the randomized Latin square crossover design, and the plasma samples were determined by a high performance liquid chromatography (HPLC) with fluorescence detector. $AUC_t,\;C_{max}\;and\;T_{max}$ were obtained from the time-plasma concentration curves, and log-transformed $AUC_t\;and\;C_{max}$ and log-untransformed $T_{max}$ values for two formulations were compared by statistical tests and analysis of variation. $AUC_t$ was determined to be $63.30{\pm}25.57{\mu}g.hr/ml$ for the test formulation and $64.02{\pm}29.27mg.hr/ml$ for the reference formulation. The mean values of $C_{max}$ for the test and reference formulations were $5.07{\pm}2.14\;and\;5.53{\pm}2.60{\mu}g/ml$, respectively. The $AUC_t,\;and\;C_{max}$ ratios of the test $Rozid^{TM}$ Tablet to the reference $Rulid^{TM}$ Tablet were -1.12% and -8.32%, respectively, showing that the mean differences were satisfied the acceptance criteria within 20%. The results from analysis of variance for log-transformed $AUC_t,\;and\;C_{max}$ indicated that sequence effects between groups were not exerted and 90% confidence limits of the mean differences for $AUC_t,\;and\;C_{max}$ were located in ranges from log 0.80 and log 1.25, satisfying the acceptance criteria of the KFDA bioequivalence. The RozidTM Tablet as the test formulation was considered to be bioequivalent to the RulidTM Tablet used as its reference formulation, based on $AUC_t,\;and\;C_{max}$ values.

• Tuberculosis and Respiratory Diseases
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• v.49 no.6
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• pp.780-784
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• 2000

Bacillus species are aerobic-gram-positive, spore forming rods that are widely distributed in soil, dust, stream, and other environmental sources and are regarded as natural organism. But certain species of the genus Bacillus, most notably B. cereus, which is associated with food-borne illness, occasionally have been implicated in the occurrence of fatal illness and complication in a compromised host. We roport a case of pneumonia and bacteremia caused by B. cereus in an 81 year-old man, who had no obvious immunologic compromise. The condition was treated with combination of roxithromycin and gentamicin.