EUROPEAN JOURNAL OF DRUG METABOLISM AND PHARMACOKINETICS, 1991, Vol. 16, No.2, pp. 137-140
Pharmacokinetics of rokitamycin after single administration to healthy volunteers 1
1
2
M. BROGGINI , V. BOTIA , C. BENVENUTI , W. FONI03, M. CONGED0 3 and J. PARINI3 1Department ofMedicine, 'Filippo Del Ponte' Hospital, Varese, Italy 2Medical Department, Prodotti Formenti, Milano, Italy 3ISF-Laboratories for Biomedical Research, Trezzano sIN, Milano, Italy
Received for publication: April 25, 1990 Keywords: Rokitamycin, pharmacokinetics, macrolides
SUMMARY The pharmacokinetics of rokitamycin tablets were studied in 12 healthy volunteers in a randomized cross-over design. The doses tested were 200 mg, 300 mg, 400 mg and 600 mg, as single oral administration. Rokitamycin was absorbed quickly with T max for all doses around 30 min after drug intake. Total AilC and Cmax values were linearly related to the administered dose. The buffer formulation determined a low interindividual variation. The overall findings show a good similarity with the data obtained in Japanese subjects. Tolerability was very good.
INTRODUCTION Rokitamycin (TMS-19-Q) is a new orally active semisyntheticmacrolide obtained from leucomycin A5 and originally developed in Japan (1). Rokitamycin inhibits protein synthesis on the bacterial wall by binding the 50S subunit of the bacterial ribosomes (1). Rokitamycin has been shown to have both bacteriostatic and bactericidal activity. Rokitamycin possesses very potent antimicrobial activity on both aerobic and anaerobic Gram-positive organisms and on some Gram-negative organisms (2). Rokitamycin.does not appear to induce resistance, and it is active against erythromycin-resistant germs, Moreover, it does not alter chemotaxis, thus it does not depress the immunological response (2).
Please send reprint requests to : Dr J Pacini, ISF Laboratories for Biomedical Research, Via L. da Vinci 1, 1-20090 Trezzano sIN (Mi), Italy
Kinetic studies in animals indicated that rokitamycin is well absorbed and distributed throughout tissues; its three major metabolites are also endowed with antibacterial activity. It is eliminated mainly through the bile and excreted without enterohepatic re-cycling (3). The absorption of macrolides in man has been found to vary widely after oral administration as they are soluble in an acidic environment, but unstable at the lowest pH values. 10 order to assure a more reliable absorption of the drug, a special formulation of rokitamycin tablets containing a glycine--citric acid buffer complex has been developed. This formulation, by keeping the gastric pH between 2.5 and 3.5, protects the molecule from breakdown (4) allowing higher plasma levels, as demonstrated in kinetic studies carried out in the Japanese population (5). The aim of this trial was to study in a Caucasian population the bioavailability characteristics of a buffered formulation of rokitamycin, after single oral administration of four different doses.
Eur. J. DrugMetab. Pharmacokinet., 1991, No.2
138
MATERIALS AND METHODS Subjects Twelve healthy volunteers (6 men and 6 women), aged (mean ± SEM) 25.3 ± 0.7 years (range 21-30) and weighing 64.8 ± 3.6 kg, gave written infonned consent to participate in the study. Before the trial, all subjects underwent an objective clinical examination and a series of routine laboratory tests (RBC and WBC count, ESR, SGOT, SGPT, alkaline phosphatase, glucose, uric acid, creatinine, cholesterol triglycerides, Na+, K+ and urinary glucose, blood proteins). SUbjects hypersensitive to macrolides, pregnant or lactating women, and subjects who had taken any drug during the receding 4 weeks, were all excluded from the trial. The subjects were instructed to maintain constant dietary and general habits through the whole period of the study.
Experimental design, treatments and sampling The experimental design adopted was a Latin-square cross-over with randomized sequences. Each subject was given the following doses of rokitamycin: 200 mg (two 100 mg tablets), 300 mg (one tablet), 400 mg (one tablet) and 600 mg (one tablet). The doses were administered according to the randomization list at one week.intervals. The tablets were taken in fasting conditions with 100 ml water at 8.00 am, just after the time 0 blood sample. Blood samples (5 ml each) were taken from an antecubital vein at time 0 and 0.25, 0.50, 1,2, 4, 6, 8 and 12 h after administration of each dose of the drug.
Assay method Plasma levels of rokitamycin were determined by a microbiological assay method (agar well diffusion method) using Micrococcus luteus ATCC 9341 as test organism (6). Immediately after sampling, human heparinized blood was treated with diisopropylfluorophosphate 0.3 M (10 ~ml of blood) to inhibit esterase activity, then plasma was separated by centrifugation. Prior to bioassay, plasma was deproteinized with acetonitrile then the supernatant was separated by centrifugation
and evaporated. The dried samples were dissolved in 0.5 ml of phosphate buffer containing acetonitrile. The standard solutions were treated and extracted with the same procedure adopted for plasma samples. The detection limit for rokitamycin in the present experimental conditions was 0.02 ll8/ml.
Pharmacokinetics and statistical analysis For each subject and for each dose of rokitamycin the following kinetic parameters were evaluated: Cmax (maximum plasma concentration at peak time), T max (time to reach maximum concentration), B (constant of the terminal elimination phase), intercept with the y axis, tIn (half-life time), and total AVC (area under the plasma concentration/time curve extrapolated to infinity). The mean values ± SEM were calculated for the plasma concentrations at the different study times, and for all kinetic parameters obtained. A dose-effect regression analysis was carried out for Cmax and AVe. Such analyses were performed on a Wang 380 PC using STATPACK statistical software and PKCALC pharmacokinetic software.
Tolerability After each treatment, possible side effects were investigated and vital signs (blood pressure and heart rate) were monitored. In addition, the routine laboratory tests carried out at baseline were repeated at the end of the trial.
RESULTS Individual and mean rokitamycin plasma concentrations after the administration of 200, 300, 400 and 600 mg are illustrated in Figures 1 and 2 respectively. The results of the phannacokinetic analysis are shown in Table I. A quick absorption of rokitamycin was observed, with Tmax values shorter than 1 h. A positive correlation with the administered dose was found for Cmax (r = 0.66, d.f. 46, P < 0.01) and for AVC (r = 0.82, d.f. 46, P < 0.01). Detectable levels of the drug were found on average up to 2 h after the administration of the 200 mg dose, up to 5 h for the 3QO and 400 mg doses, and up to 7 h for the 600 mg dose. The plasma half-life of the drug ranged between 1 and 1.5 h (Table I). No
M. Broggini et al., Pharmacokinetics ofrokitamycin
139
Table I : Phannacokinetic parameters (mean ± SEM) in 12 healthy volunteers after intake of 4 different single doses of rokitamycin
Tmax h
Cmax
B
Intercept
tin
AUCo~co
mg
J1glml
h-1
J1glml
h
J1g.hlml
200 300 400 600
0.42± 0.04 0.58 ± 0.15 0.40 ± 0.04 0.46± 0.03
0.43 ±0.04 0.54±0.04 0.79 ± 0.11 1.10 ± 0.12
0.99 ± 0.07
0.74± 0.05 1.34± 0.10 1.40 ± 0.09 1.53 ± 0.08
0.48 ± 0.03 0.83 ± 0.06 1.29 ± 0.14 1.89 ± 0.16
Dose
JIg/ml 2
------200 mg -------
0.57 ± 0.52 ± 0.73 ± 0.95 ±
0.55 ±0'04 0.52 ± 0.04 0.47 ±0.03
pg/ml 2
300 mg -------
o
o
o
J.Ig/ml 2
o
0.04 0.06 0.08 0.08
------400 mg
-_.. _---
JIg/ml 2
2
4
6
------600 mg
-------
o
Fig. 1 : Individual plasma concentrations of rokitamycin in 12 healthy volunteers after oral administration of 4 different single doses
Eur. J. Drug Metab. Pharmacokinet., 1991, No.2
140 119/ml 1.2
Z
Q
8 _ 200 mg 0 _ _0300 mg
1.0
A--"'- 400 mg
~ 0: l-
Z
l:r--t>. 500 mg
0.8
W
0 Z 0 0
0.8
c(
:::!:
en
c( ...I
0.
0.4
0.2
0.0 0
0.5
2
6
4
8
HOURS
Fig. 2 : Mean plasma concentrations (± SEM) of rokitamycin in 12 healthy volunteers after oral administration of 4 different single
doses objective signs or subjective side effects were found after administration of the 4 doses of the drug, nor were there changes in the hematological, hematochemical and vital parameters.
20-30% lower than those obtained in the Japanese population with the same dose (5). For this reason it could be suggested that the daily therapeutic dose utilized on the Japanese patients (600 mg/day), should be proportionally raised so as to obtain similar positive therapeutic results in the European population.
DISCUSSION The results of this study on kinetics of rokitamycin after single administration to 12 healthy volunteers have shown that • after oral administration, the drug is readily absorbed, Tmax values being reached in around 30 min there is a highly significant relation between dose administered and plasma levels obtained, with low variability among subjects • terminal half-life is approximately 2 h tolerability is good, even at the highest dose. These data confirm the results obtained with the same doses on the Japanese population, in particular as regards Tmax, t1l2 and low variability among subjects. One of the factors accounting for this last finding could be the buffer included in the formulation, which allows uniform dissolution and protection of the drug in an ideal pH range. Another finding was that Cmax and AUC values were about
REFERENCES Sakakibara H., Okekawa 0., Fujiwara T., Otani M, Omura S. (1981) : Acyl derivatives of 16-membered macrolides: 1. Synthesis and biological properties of 3'-0-propionylleucomycin A5 (TMS-19-Q). J. Antibiot., 34, 1001-1010. 2. Komori M., Nakazato H., Nagasawa M, Koga H., Watanabe K. (1984) : Preclinical and clinical studies onTMS-19-Q. Chemotherapy, 32, 346-357. 3. Sakai A., Suzuki T., EnOO S., Watanabe M., Morishita M. (1984) : Astudy ofabsorption, distribution, metabolism and excretion ofTMS-19-Q in experimental animals. Chemotherapy, 32, 93-98. 4. Ogata H. et al. (1984) : Development and evaluation of a new per oral test agent "GA-Test" for assessment ofgastric acidity. Dynamics, 7,656-664. 5. Morishita M, Suzuki T., Sakai A., Endo S., Watanabe M., Nagata A. (1984) : Studies onabsorption, metabolism and excretion ofTMS-19-Q in humans. Chemotherapy, 32, 99-116. 6. Morishita M, Sakai A., EnOO S., Suzuki T.(1984): Studies of the methods for measurement ofTMS-19-Q in body fluids: I. Bioassay for concentrations inbody fluids. Chemotherapy, 32, 70-79. 1.
Pharmacokinetics of rokitamycin after single administration to healthy volunteers 1
1
2
M. BROGGINI , V. BOTIA , C. BENVENUTI , W. FONI03, M. CONGED0 3 and J. PARINI3 1Department ofMedicine, 'Filippo Del Ponte' Hospital, Varese, Italy 2Medical Department, Prodotti Formenti, Milano, Italy 3ISF-Laboratories for Biomedical Research, Trezzano sIN, Milano, Italy
Received for publication: April 25, 1990 Keywords: Rokitamycin, pharmacokinetics, macrolides
SUMMARY The pharmacokinetics of rokitamycin tablets were studied in 12 healthy volunteers in a randomized cross-over design. The doses tested were 200 mg, 300 mg, 400 mg and 600 mg, as single oral administration. Rokitamycin was absorbed quickly with T max for all doses around 30 min after drug intake. Total AilC and Cmax values were linearly related to the administered dose. The buffer formulation determined a low interindividual variation. The overall findings show a good similarity with the data obtained in Japanese subjects. Tolerability was very good.
INTRODUCTION Rokitamycin (TMS-19-Q) is a new orally active semisyntheticmacrolide obtained from leucomycin A5 and originally developed in Japan (1). Rokitamycin inhibits protein synthesis on the bacterial wall by binding the 50S subunit of the bacterial ribosomes (1). Rokitamycin has been shown to have both bacteriostatic and bactericidal activity. Rokitamycin possesses very potent antimicrobial activity on both aerobic and anaerobic Gram-positive organisms and on some Gram-negative organisms (2). Rokitamycin.does not appear to induce resistance, and it is active against erythromycin-resistant germs, Moreover, it does not alter chemotaxis, thus it does not depress the immunological response (2).
Please send reprint requests to : Dr J Pacini, ISF Laboratories for Biomedical Research, Via L. da Vinci 1, 1-20090 Trezzano sIN (Mi), Italy
Kinetic studies in animals indicated that rokitamycin is well absorbed and distributed throughout tissues; its three major metabolites are also endowed with antibacterial activity. It is eliminated mainly through the bile and excreted without enterohepatic re-cycling (3). The absorption of macrolides in man has been found to vary widely after oral administration as they are soluble in an acidic environment, but unstable at the lowest pH values. 10 order to assure a more reliable absorption of the drug, a special formulation of rokitamycin tablets containing a glycine--citric acid buffer complex has been developed. This formulation, by keeping the gastric pH between 2.5 and 3.5, protects the molecule from breakdown (4) allowing higher plasma levels, as demonstrated in kinetic studies carried out in the Japanese population (5). The aim of this trial was to study in a Caucasian population the bioavailability characteristics of a buffered formulation of rokitamycin, after single oral administration of four different doses.
Eur. J. DrugMetab. Pharmacokinet., 1991, No.2
138
MATERIALS AND METHODS Subjects Twelve healthy volunteers (6 men and 6 women), aged (mean ± SEM) 25.3 ± 0.7 years (range 21-30) and weighing 64.8 ± 3.6 kg, gave written infonned consent to participate in the study. Before the trial, all subjects underwent an objective clinical examination and a series of routine laboratory tests (RBC and WBC count, ESR, SGOT, SGPT, alkaline phosphatase, glucose, uric acid, creatinine, cholesterol triglycerides, Na+, K+ and urinary glucose, blood proteins). SUbjects hypersensitive to macrolides, pregnant or lactating women, and subjects who had taken any drug during the receding 4 weeks, were all excluded from the trial. The subjects were instructed to maintain constant dietary and general habits through the whole period of the study.
Experimental design, treatments and sampling The experimental design adopted was a Latin-square cross-over with randomized sequences. Each subject was given the following doses of rokitamycin: 200 mg (two 100 mg tablets), 300 mg (one tablet), 400 mg (one tablet) and 600 mg (one tablet). The doses were administered according to the randomization list at one week.intervals. The tablets were taken in fasting conditions with 100 ml water at 8.00 am, just after the time 0 blood sample. Blood samples (5 ml each) were taken from an antecubital vein at time 0 and 0.25, 0.50, 1,2, 4, 6, 8 and 12 h after administration of each dose of the drug.
Assay method Plasma levels of rokitamycin were determined by a microbiological assay method (agar well diffusion method) using Micrococcus luteus ATCC 9341 as test organism (6). Immediately after sampling, human heparinized blood was treated with diisopropylfluorophosphate 0.3 M (10 ~ml of blood) to inhibit esterase activity, then plasma was separated by centrifugation. Prior to bioassay, plasma was deproteinized with acetonitrile then the supernatant was separated by centrifugation
and evaporated. The dried samples were dissolved in 0.5 ml of phosphate buffer containing acetonitrile. The standard solutions were treated and extracted with the same procedure adopted for plasma samples. The detection limit for rokitamycin in the present experimental conditions was 0.02 ll8/ml.
Pharmacokinetics and statistical analysis For each subject and for each dose of rokitamycin the following kinetic parameters were evaluated: Cmax (maximum plasma concentration at peak time), T max (time to reach maximum concentration), B (constant of the terminal elimination phase), intercept with the y axis, tIn (half-life time), and total AVC (area under the plasma concentration/time curve extrapolated to infinity). The mean values ± SEM were calculated for the plasma concentrations at the different study times, and for all kinetic parameters obtained. A dose-effect regression analysis was carried out for Cmax and AVe. Such analyses were performed on a Wang 380 PC using STATPACK statistical software and PKCALC pharmacokinetic software.
Tolerability After each treatment, possible side effects were investigated and vital signs (blood pressure and heart rate) were monitored. In addition, the routine laboratory tests carried out at baseline were repeated at the end of the trial.
RESULTS Individual and mean rokitamycin plasma concentrations after the administration of 200, 300, 400 and 600 mg are illustrated in Figures 1 and 2 respectively. The results of the phannacokinetic analysis are shown in Table I. A quick absorption of rokitamycin was observed, with Tmax values shorter than 1 h. A positive correlation with the administered dose was found for Cmax (r = 0.66, d.f. 46, P < 0.01) and for AVC (r = 0.82, d.f. 46, P < 0.01). Detectable levels of the drug were found on average up to 2 h after the administration of the 200 mg dose, up to 5 h for the 3QO and 400 mg doses, and up to 7 h for the 600 mg dose. The plasma half-life of the drug ranged between 1 and 1.5 h (Table I). No
M. Broggini et al., Pharmacokinetics ofrokitamycin
139
Table I : Phannacokinetic parameters (mean ± SEM) in 12 healthy volunteers after intake of 4 different single doses of rokitamycin
Tmax h
Cmax
B
Intercept
tin
AUCo~co
mg
J1glml
h-1
J1glml
h
J1g.hlml
200 300 400 600
0.42± 0.04 0.58 ± 0.15 0.40 ± 0.04 0.46± 0.03
0.43 ±0.04 0.54±0.04 0.79 ± 0.11 1.10 ± 0.12
0.99 ± 0.07
0.74± 0.05 1.34± 0.10 1.40 ± 0.09 1.53 ± 0.08
0.48 ± 0.03 0.83 ± 0.06 1.29 ± 0.14 1.89 ± 0.16
Dose
JIg/ml 2
------200 mg -------
0.57 ± 0.52 ± 0.73 ± 0.95 ±
0.55 ±0'04 0.52 ± 0.04 0.47 ±0.03
pg/ml 2
300 mg -------
o
o
o
J.Ig/ml 2
o
0.04 0.06 0.08 0.08
------400 mg
-_.. _---
JIg/ml 2
2
4
6
------600 mg
-------
o
Fig. 1 : Individual plasma concentrations of rokitamycin in 12 healthy volunteers after oral administration of 4 different single doses
Eur. J. Drug Metab. Pharmacokinet., 1991, No.2
140 119/ml 1.2
Z
Q
8 _ 200 mg 0 _ _0300 mg
1.0
A--"'- 400 mg
~ 0: l-
Z
l:r--t>. 500 mg
0.8
W
0 Z 0 0
0.8
c(
:::!:
en
c( ...I
0.
0.4
0.2
0.0 0
0.5
2
6
4
8
HOURS
Fig. 2 : Mean plasma concentrations (± SEM) of rokitamycin in 12 healthy volunteers after oral administration of 4 different single
doses objective signs or subjective side effects were found after administration of the 4 doses of the drug, nor were there changes in the hematological, hematochemical and vital parameters.
20-30% lower than those obtained in the Japanese population with the same dose (5). For this reason it could be suggested that the daily therapeutic dose utilized on the Japanese patients (600 mg/day), should be proportionally raised so as to obtain similar positive therapeutic results in the European population.
DISCUSSION The results of this study on kinetics of rokitamycin after single administration to 12 healthy volunteers have shown that • after oral administration, the drug is readily absorbed, Tmax values being reached in around 30 min there is a highly significant relation between dose administered and plasma levels obtained, with low variability among subjects • terminal half-life is approximately 2 h tolerability is good, even at the highest dose. These data confirm the results obtained with the same doses on the Japanese population, in particular as regards Tmax, t1l2 and low variability among subjects. One of the factors accounting for this last finding could be the buffer included in the formulation, which allows uniform dissolution and protection of the drug in an ideal pH range. Another finding was that Cmax and AUC values were about
REFERENCES Sakakibara H., Okekawa 0., Fujiwara T., Otani M, Omura S. (1981) : Acyl derivatives of 16-membered macrolides: 1. Synthesis and biological properties of 3'-0-propionylleucomycin A5 (TMS-19-Q). J. Antibiot., 34, 1001-1010. 2. Komori M., Nakazato H., Nagasawa M, Koga H., Watanabe K. (1984) : Preclinical and clinical studies onTMS-19-Q. Chemotherapy, 32, 346-357. 3. Sakai A., Suzuki T., EnOO S., Watanabe M., Morishita M. (1984) : Astudy ofabsorption, distribution, metabolism and excretion ofTMS-19-Q in experimental animals. Chemotherapy, 32, 93-98. 4. Ogata H. et al. (1984) : Development and evaluation of a new per oral test agent "GA-Test" for assessment ofgastric acidity. Dynamics, 7,656-664. 5. Morishita M, Suzuki T., Sakai A., Endo S., Watanabe M., Nagata A. (1984) : Studies onabsorption, metabolism and excretion ofTMS-19-Q in humans. Chemotherapy, 32, 99-116. 6. Morishita M, Sakai A., EnOO S., Suzuki T.(1984): Studies of the methods for measurement ofTMS-19-Q in body fluids: I. Bioassay for concentrations inbody fluids. Chemotherapy, 32, 70-79. 1.
