Jan. THE JAPANESE JOURNAL OF XXXIX-1 109 (109) 1986

PHARMACOKINETICS OF IN THE EXUDATE FROM WOUNDS OF PATIENTS WITH BREAST CANCER OPERATED UPON FOR RADICAL MASTECTOMY

EIJI MIZUTA and YASUKO KANEKO Central Research Division, Takeda Chemical Industries, Ltd., Osaka, Japan

HIROYUKI NISHINDAI, MASANORI YOSHIMOTOand YOSHIMI NAKANISHI The First Surgical Department, School of Medicine, Hokkaido University , Sapporo, Japan, IKUO HASHIMOTO, YASUO SAWADA, TAKASHI NAKAMURAand JIROH MIKAMI Department of Surgery, Tenshi General Hospital, (St. Franciscan Missionaries of Mary) Sapporo, Japan

(Received for publication May 14, 1985)

Cephalosporin antibiotics have been widely used to prevent infections during and after operation . To establish an efficient use of prophylactic antibiotics for patients undergoing surgery , it is important to investigate the drug levels in exudate from wounds of the patients and to elucidate the relation be-

tween drug concentration in the blood and that in the exudate. In a previous paper1) , the present authors (except E. M. and Y. K.) determined cefotiam (CTM) concentrations in serum and exudate

from wounds of patients with breast cancer who underwent radical mastectomy and discussed an ade-

quate regimen of CTM prophylaxis after the operation. However, CTM concentrations in serum and

exudate from the wounds of the patients were not analyzed pharmacokinetically.

In the present paper we report on the disposition kinetics of CTM in serum and exudate from

wounds after the administration of CTM following bolus intravenous injection into patients with breast

cancer operated upon for radical mastectomy.

Materials and Methods

1.

The antibiotic used in this study was CTM (Pansporin(R), Takeda , Japan) in vials containing the dihydrochloride equivalent to 1 g CTM. 2. Patients The of CTM were studied in patients with breast cancer after radical mastectomy (16 females; 54.3•}6.4 kg, 48.1•}12.4 years). All the patients had normal kidney and liver functions. Six patients were used for the analysis of CTM levels in serum and 15 patients for that of CTM levels in exudate from the wound. 3. Administration of antibiotic and collection of samples All patients received 2 g of CTM dissolved in 20 ml of physiological saline following bolus intra- venous injection over about 5 minutes. Blood samples were collected at appropriate intervals after the injection. The serum was separated by centrifugation and frozen at -20•Ž until analysis . Exudate samples from drainage were taken by sterilized paper disks at 0.5, 1, 2, 3, 4, 5 and 6 hours after the injection. The sample disks were stored in eppendorf 1.5 ml microtubes at -20•Ž until analysis . 4. Microbiological assay The concentration of CTM in serum and exudate was determined by a microbiological plate- diffusion method using Proteus mirabilis ATCC 21100 as the test organism2). Standard solutions of CTM in human serum were prepared at concentrations between 0.62 and 20ƒÊg/ml for serum assay, and Jan. 110 (110) THE JAPANESE JOURNAL OF ANTIBIOTICS XXXIX-1 1986

Fig. 1. Schematic diagram of the modified three-compartment model

C1, V1: Concentration and distribution volume of drug in compartment 1 (Serum) C2, V2: Concentration and distribution volume of drug in compartment 2 (Inter- mediate compartment) C3, V3: Concentration and distribution volume of drug in compartment 3 (Exudate) k1, k_1, k2, k_2: Transfer rate constants between compartments 1 and 2, and compartments 2 and 3 those in 0.1 M phosphate buffer (pH 7.0) at con- Table 1. Pharmacokinetic parameters ob- tained from the serum CTM levels of centrations between 0.8 and 100ƒÊg/ml for exudate patients with breast cancer operated upon assay. The lower limit of detection in the method for radical mastectomy following bolus was approximately 0.3ƒÊg/ml and its standard intravenous injection of 2 g CTM (n=6) deviation was less than 12%. 5. Pharmacokinetic analysis Pharmacokinetic analysis of CTM levels in the serum was performed based on the usual two- compartment open model. The serum concen- tration (C1) following bolus intravenous injection is expressed by the well-known equation 1, where (1)

V1 is the apparent volume of distribution in the first (serum) compartment, D is a dose, ƒ¿ and ƒÀ AUC: Area under the serum concentration- are the hybrid rate constants, k21 is the transfer time curve rate constant from the second compartment to the first compartment. The optimum values of parameters A11, Al2, a and ƒÀ were determined by the com- bined use of a least-squares method and a steepest descent method3) to minimize the sum of weighted sauares of differences between the observed values and the values calculated from Eq. 1. The CTM levels in the exudate were analyzed with a modified three-compartment model" shown in Fig. 1 taking into account that CTM is transferred indirectly from blood to exudate through an inter- mediate compartment, since the drug concentration in the exudate gradually rises after the administra- tion. The first (serum) compartment of the usual two-compartment open model is shown as compart- ment 1 in Fig. 1, while the second compartment is not shown. Instead, an additional compartment corresponding to exudate is linked indirectly to the serum compartment through the intermediate one. In Fig. 1, C1 and Vi represent the concentration and distribution volume of drug in compartment i, respectively, while k1 and k_1, and k2 and k_2 are the transfer rate constants between compartments 1 and 2 and compartments 2 and 3, respectively. In the modified three- compartment model, the drug concentration in compartment 3 (exudate) is given by Eq. 2 on the assumption that the intermediate compartment kinetics exactly parallel those of the drug in the second compartment of the usual two-compartment open model, that is, k_1 in Fig. 1 is equal to ( 2 ) Jan. THE JAPANESE JOURNAL OF ANTIBIOTICS XXXIX-1 111 (111) 1986

Fig. 2. Concentrations (mean•}S.E.) and mean pharmacokinetic profile in the serum of 6

patients with breast cancer operated upon for radical mastectomy following bolus intrave- nous injection of 2 g CTM

Table 2. Pharmacokinetic parameters (geometrical mean) obtained from the CTM levels in exudate from wounds of patients with breast cancer operated upon for radical mastectomy following bolus intravenous injection of 2 g CTM

*: Calculated from the mean pharmacokinetic profiles in exudate

k21. In Eq. 2, F2 is the apparent transfer ratio from serum to exudate and theoretically equals the ratio between the area under the drug concentration-time curve in the exudate and that in the serum. The parameters to be determined in Eq. 2 are F2 and k_2, since ƒ¿, ƒÀ, k21, and V1 are obtained from analyzing CTM levels in the serum. The optimum values of F2 and k_2 were determined to minimize the sum of weighted squares of differences between the observed values and the values calculated from Eq. 2.

Results

The CTM levels in the sera of 6 patients were analyzed individually with the usual two-compartment open model to afford the pharmacokinetic parameters listed in Table 1. The mean serum concentration- time curve, prepared by using the geometrical means') of individual a's, P's, kn's and V1's, are shown in Fig. 2. The values of elimination half-life (T1/2ƒÀ), V1, distribution volume of jS-phase (Vd), and serum 112 (112) THE JAPANESE JOURNAL OF ANTIBIOTICS XXXIX-1 Jan. 1986

Table 3. Pharmacokinetic parameters (arithmetic mean•}S.D.) obtained from the CTM levels in exudate from wounds of patients with breast cancer operated upon for radical mastectomy following bolus intravenous injection of 2 g CTM and the analysis of variance for them

*: F-value (F12(0.05)=4.02, F12 (0.01)=7.15)

Fig. 3. Concentrations (mean•}S.E.) and mean pharmacokinetic profiles in the exudate from

wounds of patients with breast cancer operated upon for radical mastectomy following bolus intravenous injection of 2 g CTM

clearance (C1) were similar to those obtained from the analysis of serum CTM levels of patients under- going thoracic surgery4).

As the exudates and blood samples were not necessarily taken from the same patients, the CTM

levels in the exudates of individual patients were analyzed with Eq. 2 using the values of ƒ¿,ƒÀ, k21, and Vi

used to prepare the mean serum concentration-time curve shown in Fig. 2, and the optimum values of Jan. THE JAPANESE JOURNAL OF ANTIBIOTICS XXXIX-1 113 (113) 1986

Fig. 4. Changes in mean pharmacokinetic profiles in the exudate from wounds of patients with breast cancer operated upon for radical mastectomy following bolus intravenous injection of 2 g CTM according to days after the operation

k_, and F2 were determined. The mean pharmacokinetic profiles of CTM in the exudates were pre- pared using the geometrical means of individual k and F2, and peak drug concentrations (Cma.), times of peak drug concentrations (Tma.), and elimination half-lives (T1/2 x, x is the smaller of j9 and k_2) were computed from the profiles. The values of 1C-2, F2, Cmax, T., and T1/2 x obtained during the first 6 days after the operation are listed in Table 2. The mean pharmacokinetic profiles are shown in Fig. 3, and changes in them during the first 6 days after the operation are shown in Fig. 4. As shown in Fig. 4, a considerable change occurs between the pharmacokinetic profiles during the first 3 days and those during the next 3 days. During the first 3 days, the values of k_ 2, C.a. and Tmaz ranged from 1.91 to 1.96 hr-1, 36.2 to 41.5ƒÊg/ml, and 1.15 to 1.17 hours after the administration, respectively. Thereafter they were in the range of 0.56 to 0.76 hr -1, 21.0 to 27.6ƒÊg/ml, and 1.73 to 1.97 hours, respectively.

On the other hand, the values of F2 changed little during the first 6 days after the operation. The values of T1/2 x on the 6th day was a little longer than those on the first 5 days. The arithmetic means of individual k-21 F2, Cmax, Tmax and T1/2 x are summarized in Table 3 with the F-values

obtained from the analysis of variance for them. The results in Table 3 show that the differences be- tween the mean values of individual parameters during the first 3 days and those during the next 3 days were highly significant for k _ 2 and Tma., significant for Cma. and T1/2 x, and insignificant for F2.

Discussion

Studies on the analysis of drug concentration in body fluids and tissues after the administration of antibiotics have been reported, mainly in the field of obstetrics and gynecology13-8),to evaluate the clinical utility of new antibiotic agents for treating or preventing infections during and after operation. Recent- ly, drug concentrations in pleural effusion4,9-11) and burn blister fluid4'12-14)after the intravenous injec- tion of antibiotic agents have also been analyzed pharmacokinetically. However, no study has been reported in which drug concentrations in the exudate from wounds of patients were analyzed systema- tically during a period of a number of days after an operation. In this paper, although the pharma- cokinetic parameters were not necessarily obtained from the same number of patients, the mean pharma- cokinetic profiles shown in Fig. 4 are reasonable judging from the changes in the mean values of k_,, F2 and T1/2 x obtained on the days after the operation. The changes in the profiles shown in Fig. 4 suggest that the wounds of patients with breast cancer who are operated upon for radical mastectomy recovered considerably on the 4th day after the operation, although interindividual differences in the profiles are large. The result is consistent with the fact that the mean concentration of hemoglobin in 114(114) THE JAPANESE JOURNAL OF ANTIBIOTICS XXXIX-1 Jan. 1986

the exudate from wounds decreased from 12.3% of that in blood on the 3rd day to 5.35% on the 4th day, the values of the 5th and 6th day were 4.25% and 4.01%, respectively. The low Cma= and slow Tin,. values of the profiles in Fig. 4 on the 4th, 5th, and 6th day after the operation are attributed to the small values of k _2, since the values of F2 are approximately constant during the first 6 days after operation. The values of 1.02 from 1.42 for F2, which are similar to the value (F2 =1.02) obtained from the analysis of CTM levels in pleural effusiono, show that the transfer of CTM from blood to the exudate is fairly good and CTM is useful for preventing infections after radical mastectomy for breast cancer.

Summary

Cefotiam (CTM) levels in the exudate from wounds of patients with breast cancer who were operated upon for radical mastectomy were analyzed with a modified three-compartment model for a number of days after the operation. A considerable change was observed between the mean pharmacokinetic profiles in the exudate during the first 3 days after the operation and those during the next 3 days. Dur- ing the first 3 days, the peak concentrations (Cnia.) and times of the peak concentrations (r..) calculated from the profiles ranged from 36.2 to 41.5 1ig/m1 and 1.15 to 1.17 hours after the administration, res- pectively. Thereafter they were in the range of 21.0 to 27.6 tig/m1 and 1.73 to 1.97 hours, respectively. The low Cm.. and slow Tnia. values of the profiles from 4 to 6 days after the operation were attributed to a decrease of the transfer rate constant from the exudate to blood. On the other hand, the apparent transfer ratios (F2) of CTM from blood to the exudate were approximately constant for the 6 days.

The mean value of individual elimination half-lives in the exudate during 4,N, 6 days was statistically longer than that during the first 3 days. It was clear that the transfer of CTM from blood to the exudate from wounds of patients with breast cancer who were operated upon for radical mastectomy is fairly good judging from the large values of 1.02 to 1.42 for F2.

References

1) HASHIMOTO, I. ; Y. SAWADA, T. NAKAMURA, J. MIKAMI, H. NISHINDAI, M. YOSHIMOTO, Y. NAKANISHI, T. FUGONO & K. MAEDA: Cefotiam concentration in exudate from suction drain of patients with breast cancer following intravenous administration. Jap. J. Antibiotics 39: 99•`108, 1986 2) NISHINDAI, H.; M. NAKANISHI, Y. KASAI, I. HASHIMOTO, Y. SAWADA, T. NAKAMURA, T. FUGONO & K. MAEDA: Studies on the method to determine antibiotic concentrations in slight amounts of the exudate. Jap. J. Antibiotics 36: 3412•`3421, 1983 3) OUCHIDA, A.; E. MIZUTA & T. SHIMA: Simulation of blood level of drugs by digital computer. J. Takeda Res. Lab. 32: 522•`531, 1973 4) MIZUTA, E. & A. TSUBOTANI: A pharmacokinetic model for simulating drug concentrations in tissues or fluids and its application to antibiotics. Chem. Pharm. Bull. 33: 2974•`2982, 1985 5) MIZUTA, E. & A. TSUBOTANI: Preparation of mean drug concentration-time curves in plasma. A study on the frequency distribution of pharmacokinetic parameters. Chem. Pharm. Bull. 33: 1620•`1632, 1985 6) Research Group in Obstetric and Gynecological Infection: Basic and clinical evaluation on sulbenicillin (SBPC) in the field of obstetrics and gynecology. World Obstetr. & Gynecol. 31: 917•`939, 1979 7) CHO, N.; K. KUNII, K. FUKUNAGA, K. DEGUCHI, H. ARAI, Y. NAKAJIMA, M. NOGUCHI & T. HAYASHI: Laboratory and clinical studies on . Chemotherapy (Jap.) 29: 53•`67, 1981 8) IWASA, S.; A. ITOH, M. HAYASAKI, S. SHIRAKI, K. NODA, T. FUGONO & E. MIZUTA: Transfer of cefacetrile (CEC) to female reproductive organs. World Obstetr. & Gynecol. 34: 759•`766, 1982 9) MATSUURA, Y.; M. TAMURA, H. YAMASHINA, M. HIGO & T. FUJII: Experimental and clinical studies of cefotiam in thoracic surgery. Jap. J. Antibiotics 36: 537•`546, 1983 10) OTERO, M. J .; M. J. GARCIA, M. BARRUECO, A. DOMINGUEZ-GIL, F. GOMEZ & J. P. ALVAREZ: Pharma- cokinetics of administered by i.v. infusion to patients with a pleural effusion. Eur. J. Clin. Phar- macol. 26: 389•`392, 1984 11) LASTRA, C. F.; E. L. MARINO, M. BARRUECO, M. S. GERVOS & A. DOMINGUEZ-GIL: Disposition of pho- sphomycin in patients with pleural effusion. Antimicr. Agents & Chemoth. 25: 458•`462, 1984 Jan. THE JAPANESE JOURNAL OF ANTIBIOTICS XXXIX-1 115 (115) 1986

12) LASTRA, C. F.; E. L. MARINO, A. DOMINGUEZ-GIL, J. M. TABERNERO, A. G. LOPEZ & M. Y. CHAVES: The

influence of uremia on the accessibility of phosphomycin into interstitial tissue fluid. Eur. J. Clin. Phar- macol. 25: 333•`338, 1983

13) NISHIZAKI, A.; H. AOYAMA, T. KOH & Y. IzAwA: Transfer of to burn blister fluids. Jap. J. Antibiotics 37: 295•`302, 1984

14) ABE, M.; A. NISHIZAKI, H. AOYAMA, Y. IzAwA, T. FUGONO & E. MIZUTA: Pharmacokinetic studies on cefotiam in human burn fluids. J. New Remed. & Clin. 33: 737•`741, 1984