Serum Levels After Oral Administration of Terramycin Base*JJt

By RACHEL MASON, PATRICIA KICE, ELDON L. CAFFERY, and M. M. MUSSELMAN

A comparison was made of the level of terra- mycin obtained in the serum of patients after single oral doses of terramycin base and terra- mycin hydrochloride. Serum levels were de- termined by a tube dilution method. The serum levels obtained after terramycin base were comparable to those obtained after terra- mycin hydrochloride. It is concluded that the two substances are absorbed equally well.

HERAPEUTICALLY effective levels of terra- Tmycin may be produced in the blood serum by oral administration of terramycin hydro- chloride (1, 2). Terramycin hydrochloride is a salt of the amphoteric parent substance, terra- mycin base. I n order to estimate the possible effectiveness of terramycin base as a therapeutic agent we have compared the levels of terramycin in the blood serum after single oral doses of the base and the hydrochloride.

METHOD

Serum levels of terramycin were determined by a tube dilution method in which the final total volume was 2 ml. (3 ,4) . Brain heart infusion broth (Difco) was the medium and diluent, and the test organism was a stock strain of an F. D. A. Micrococcus pyo- genes var. aureus, which was employed in a dilution of 1: 10,000 in an eighteen-hour broth culture. The stock standard of the drug was a solution of 200 pg. of crystalline terramycin hydrochloride in 1 ml. of broth. One hundred milligrams of the terramycin was weighed on an analytical balance and dissolved in 500 ml. of broth. The solution was then passed through a Seitz filter. This stock standard was pre- pared once a week and stored in the refrigerator a t 4'. The working standard of terramycin, contain- ing 1 pg./ml., was prepared daily from the stock standard by diluting it 1:200 with broth.

Terramycin was administered to patients orally a t 8:OO a. m., and blood samples were drawn at 9:00 a. m., 1O:OO a. m., 12:OO noon, 2:OO p. m., and at 8:OO a. m. the next day. The samples were refriger- ated until all were collected. The storage period did not affect the concentration of terramycin in the serum.

Two parallel series of constituents were set up in tubes as shown in Table I. Both series of tubes were incubated at 37' overnight. The tube of highest dilution showing complete inhibition indicated the

* Received July 9, 1951, from the Departments of Patho- logy, Ulology! and Surgery. Wayne County General Hospi- tal. Eloise. Mich. i Presented s% Regional Meeting of the Ametican Pedera-

This investigation has been supported in part by Chas. tion for Clinical Research, Detroit, Mich., March 2. 1951.

Pfizer and Co.. Inc., Brooklyn. N. Y.

end point. The strain of M. pyogenes var. aureus was usually inhibited by 0.15 to 0.25 pg. of terramy- cin hydrochloride per milliliter of broth. The serum concentration of terramycin, in pg./ml., was ob- tained by multiplying the highest dilution of serum showing no growth by the smallest concentration per milliliter of terramycin hydrochloride showing no growth. The range of the concentration of terra- mycin which could be measured in serum by this procedure was from 0.3 to 12.0 pg./ml.

Tests were conducted on a total of 36 patients, consisting of three groups of 12. The patients in group I received 1.0 Gm. of terramycin base orally in a single dose; those in group 11, 2.0 Gm.; and those in group 111, 3.0 Gm. Senun levels of terra- mycin were determined at one, two, four, six, and twenty-four hours after administration of the drug. For control, parallel tests were made using terra- mycin hydrochloride, giving similar doses to the Same patients.

GROUP FSEWM LEVELS AFTER SINGLE ORAL DOSE OF 1.0 0.

TERRAYYCIN BASE--- TERRAUWN n c ~ -

2 2 2 0

12 ^ ^

I P 4 0 0 10 12 14 16 IS 20 24

HOURS AfTER ACUNISTRATIW

Figure 1

GROUP 11-SERUM LEVELS AFTER SINGLE ORAL DOSE OF Z O GY

A" 0 6 0.4 L.2 I \

1.4

l i I0 .

0 1 -_ 0 4 . . 0 6 %.

0 2

I I 4 6 8 10 I0 14 16 10 20 22 24

HOURS AFTER AODYINISTRATION

Figure 2

588 JOURNAL OF TEE AMERICAN ~ C E U T I c h c ASSOCIATION

TABLE I.-TuBE DILUTION METHOD FOR DETERMINING SERUM CONCENTRATIONS OF TERRAMYCIN

Terramycin Standard

Vol. XL, No. 11

Tube No. + 1 2 3 4 5 6 7 8 9 10 Terramycin in broth (1 pg. /ml . ) ,

ml. 1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 Broth, ml. 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1:10,000dilutionM.aursus.ml. 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Final concentration of terramy- cin (pg./ml.) 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05

Serum Sample Tube No. -c 1 2 3 4 5 6 7 8 9 10 11

Serum, ml. 1.0 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 Broth, ml. 0 0.5 0.55 0.6 0.65 0.7 0.75 0.8 0.85 0.9 0.95 1 : 10,000 dilution M. au-

reus, ml. 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 1.0 Final concentration of serum, ml. 0 . 5 0.25 0.225 0.2 0.175 0.15 0.125 0.1 0.075 0.05 0.025

Finaldilutionofserum 1:2 1:4 1:4.4 1:5 1:5.7 1:6.7 1:s 1:lO 1:13.3 1:20 1:40

In order to evaluate the possible influence of age on absorption of tcrramycin. cach group of 12 sub- jects was composed of four patients between the ages of 18 and 40 years, four between the ages of 40 and 60 years, and four over GO years of age. In order to evaluate the possible influence of gastric acidity on absorption, the gastric juice of each patient was analyzed for free hydrochloric acid and PH value in the fasting state and for frec hydrochloric acid after stimulation by histamine, before administration of the base and before administration of the hydro- chloride.

RESULTS

Some patients had higher serum levels after administration of the base while others had higher levels after administration of the hydro- chloride. But, as shown graphically in Figs. 1, 2, and 3, there was no marked difference between the average serum levels after tenamycin hydro- chloride and those after terramycin base.

Statistical analysis of the tabulated figures by Professor Donald Mainland of New York Univer- sity revealed no suggestion of a significant differ- ence in serum level a t six hours. In the case of the four-hour levels, he felt the considerable variation in the results made the difference not significant. These determinations indicate that terramycin base is absorbed as well as terramycin

GROUP Ill -SERUU LEVELS AFTER SINGLE ORPlL DOSE OF 3.0 GY.

I

'2 - I 10

0 8 -4

0 6 - 0 4 - 0 2 -

Y C G / Y L o ' I I 2 4 6 I 10 12 14 16 I8 20 2 2 24

' I ' I ' I ' I " ' WURS AFTER IDYINISTRATION

Figure 3

The data accumulated were not significant in regard to the relation of variations in serum levels to differences in ages of patients or gastric acidity.

REFERENCES

(1) Herrell W. E. Heilman F. R. Wellman W. E. and Bartholomew: L. G..' Proc. Sf6ff Meeiings Mayb Clinic', 25. 183(1950).

(2) Schoenbach, E. B.. Rryer, M. S., Long, P. H., Ann. N. Y. Accd. Sci.. 53.245(1050).

(3) Welch H. Hendricks F. D. Price, C. W., and Randall,

(4) Price C. W. Randall, W. A.. Welch, H.. Ann. N. Y. w . A,, THIS'JO~RNAL. 39, is5(19bo).

hydrochloride. Acad. Scr.. '51, 211'(1948).