JPH0278695A - Erythromycin derivative - Google Patents

Abstract

NEW MATERIAL:12-Di-O-methylerythromycin A and 6-O-(methyl-12-O- methylthiomethyl) erythromycin A of the formula and salts thereof. USE:An antibiotic. The erythromycin derivatives of the formula exhibit improved absorbing property and tissue-transferring property. PREPARATION:6-O-Methylerythromycin A is reacted with allyl chloroformate to give 2-O,3-N-bis(allyloxycarbonyl) derivative, which is reacted with a trimethylsilylating agent in an inactive solvent to prepare 4''-O-trimethylsilyl derivative. The derivative is reacted with allyl bromide in the presence of a base in an aprotic dipolar solvent and the resultant 11-O-allyl derivative is reacted with a methylating agent in the presence of a base to give a 12-O-methyl derivative. The 12-O-methyl derivative is reacted with palladium acetate and triphenyl phosphine in the presence of formic acid (salt) and the reaction product is subjected to a reductive N-methylation reaction using formaldehyde and formic acid to regenerate the dimethylamino group.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to antibiotics that can be used in chemotherapy for bacterial infections, and more particularly to antibiotics that have high antibacterial activity and improved absorption and tissue penetration. The present invention relates to erythromycin derivatives and pharmaceutically acceptable salts thereof.

Erythromycin is widely used clinically and exhibits desirable antibacterial activity against many Durham-positive bacteria, some Durham-negative bacteria, and mycoplasma. However, erythromycin is extremely unstable under acidic conditions, and when administered orally, it is rapidly decomposed in the stomach and becomes an inactive form, resulting in a low blood concentration. Therefore, higher doses are required when a sufficient effect is expected for the treatment of infectious diseases, but side effects may become a problem.

Many derivatives of erythromycin have been produced to improve its biological and/or pharmacological properties. For example, the 6-0-methyl form or 6.11-di-O-methyl form of erythromycin is more stable under acidic conditions than erythromycin, and has better antibacterial activity, especially in vivo antibacterial activity when administered orally. (U.S. Pat. No. 4,331,803 and U.S. Pat. No. 4,496,717).

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a novel antibiotic that has even higher efficacy and is pharmacologically superior.

Means for Achieving the Problem: The inventors obtained an erythromycin derivative exhibiting strong antibacterial activity by converting both the hydrogen atoms of the two tertiary hydroxyl groups (6-position and 12-position) present in erythromycin A. It was unexpectedly discovered that the blood concentration and the white concentration in each organ were higher than those of conventional erythromycin derivatives, and the present invention was completed.゛That is, the compound of the present invention comprises 6.12-di〇-methylerythromycin A and 6-0-methyl-12-0
- (Methylthiomethyl)erythromycin A and their pharmaceutically acceptable salts 8 of the present invention 6,12-
Di-O-methylerythromycin A and 6-0-methyl-12-0-(methylthiomethyl)erythromycin A can be represented by the following structural formula (in the structural formula, R
is a methyl group or a methylthiomethyl group. ).

In the present invention, pharmaceutically acceptable salts are defined as salts that can be used in contact with human and lower animal tissue within the scope of sound medical judgment and without undue toxicity, irritation, or allergy. refers to salts which are suitable for use in the treatment of bacterial infections and are effective for the intended use in the chemotherapy and prevention of bacterial infections. They are, for example, acetic acid, propionic acid, acetic acid, formic acid, trifluoroacetic acid, maleic acid, tartaric acid, citric acid, stearic acid, succinic acid, ethylsuccinic acid, lactobionic acid, gluconic acid, glucoheptonic acid, benzoic acid, methanesulfonic acid, Ethanesulfonic acid, 2
-Hydroxyethanesulfonic acid, benzenesulfonic acid,
Paratoluenesulfonic acid, lauryl sulfate, malic acid, aspartic acid, glutamic acid, adipic acid, cysteine, hydrochloric acid, hydrobromic acid, phosphoric acid, sulfuric acid, hydroiodic acid, nicotinic acid, oxalic acid, picric acid, thiocyanic acid, Salts with acids such as undecanoic acid, acrylic acid polymers and carboxyvinyl polymers can be mentioned.

The compound of the present invention can be produced, for example, as follows.

6-0-Methylerythromycin A is reacted with allyl chloroformate to form the 2'-0,3'-N-bis(allyloxycarbonyl) form, and then treated with a suitable reaction inert solvent (e.g., acetonitrile, dichloromethane,
4″
−〇-tritylsilyl compound. Here, as the trimethylsilylating agent, chlorosilanes such as trimethylchlorosilane or trimethylsilylimidazole, 1.
Silylamines such as 1.1.3.3.3-hexamethyldisilazane are used alone or in combination. When using chlorosilanes alone, it is desirable to coexist with an appropriate organic base such as triethylamine, tribenzylamine, pyridine, picoline, etc. When using silylamines, it is preferable to use them in combination with ammonium chloride, pyridine hydrochloride, etc. , in an aprotic dipolar solvent in the presence of a base, react allyl bromide to form a 11-0-allyl compound, and then react with a methylating agent in the presence of a base 1
2-O-methyl compound is obtained. Here, as the aprotic dipolar solvent, N,N-dimethylformamide, dimethyl sulfoxide, 1-methyl-2-pyrrolidinone, etc. are used. or any of these and tetrahydrofuran,
A mixture of 1.2-dimethoxyethane, dioxane, ethyl acetate, etc. can be used. As the base, sodium hydride, potassium hydride, sodium hydroxide, potassium hydroxide, etc. can be used, and as the methylating agent, methyl iodide, methyl bromide, dimethyl sulfate, para-toluenesulfonic acid methyl ester, toluenesulfone can be used. Acid methyl ester and the like are used.

The protecting groups are subsequently removed by reaction with palladium acetate and triphenylphosphine in the presence of formic acid or formate salts in a suitable solvent, followed by a reductive N-methylation reaction using formaldehyde and formic acid to remove the dimethylamino group. The desired 6,12-di-O-methylerythromycin A can be obtained by regenerating the . Examples of the solvent used here include aqueous ethanol and aqueous dioxane, and examples of the formate include ammonium formate, trimethylammonium formate, trimethylammonium formate, sodium formate, and potassium formate.

On the other hand, 6-0-methyl-12-0-C methylthiomethyl)erythromycin A can be produced by the following method. That is, 6-0-methylerythromycin A
is reacted with 2'-0,3'-N-bis(allyloxycarbonyl) obtained as described above to form a 4",11-bis(trimethylsilyl) body.

Next, this was reacted with a mixture consisting of acetic anhydride and dimethyl sulfoxide to produce 12-.

-Methylthiomethyl compound is obtained. After removing the trimethylsilyl group using tetra-n-butylammonium fluoride and removing the allyl group in the same manner as above, the dimethylamino group is regenerated by a reductive N-methylation reaction to obtain the desired product. .

The compounds obtained in each reaction step can be purified by recrystallization, silica gel column chromatography, etc., if necessary.

The starting material 6-0-methylerythromycin A used in the present invention is disclosed in Japanese Patent Publication No. 61-52839 (
U.S. Patent No. 4. 331. It is produced according to the method described in 803 specification a) or JP-A-61-103890.

Mars'' Next, the method for producing the compound of the present invention will be explained in more detail with reference to Examples.

Example 1 6,12-di-O-methylerythromycin A (1) 6-0-Meflue IJ Sl:t-
v4'inA (30g.

0.04 mol) and sodium bicarbonate (27 g, 0
．． 321 mol> in 100 mft of dioxane,
Allyl chloroformate (34 ml,
0.32 mol) was added dropwise. After stirring for 1.5 hours, n-hexane was added to the reaction solution, and the precipitated crystals and sodium hydrogen carbonate were collected by filtration. After washing the crystals with n-hexane, the crystals were dissolved with dichloromethane to remove remaining sodium hydrogen carbonate, and then dichloromethane was distilled off under reduced pressure.

The residue was dissolved in ethyl acetate <50 ml)-n-hexane (12
0td) to give 34.95 g of 2'-0-allyloxycarbonyl- -methyl-3'-[methyl(allyloxycarbonyl)
Aminocoerythromycin A was obtained as a white powder.

1!1. p. 174-175℃' H-NMR (200MHz, CD
CI! 3) S = 1, 38 (s. 3H. 6
-CHa).

2, 82 (s. 3H. NCHs).

3, 03 (s. 31. 6-OCHs).

5, 82 = 6.04 (m.2H. allyl proton) (2
) The compound obtained in (1) above (20 g, 0.022 mol) was added to N. N-dimethylformamide (200ml)
Dissolved in trimethylchlorosilane (4.2 m
ll, 0. 033 mol) and triethylamine (1
5. 4m11, 0. 11 mol) and 0 to 5
The mixture was stirred at °C for 3.5 hours. After the reaction was completed, a saturated aqueous sodium carbonate solution was added, extracted with ethyl acetate, and the ethyl acetate layer was washed with saturated brine. The ethyl acetate layer was dried over anhydrous magnesium sulfate, and the solvent was distilled off under reduced pressure to obtain a residue 20. 5 g was purified by silica gel column chromatography (elution solvent: ethyl acetate: n-hexane-1:3), and 15.07 g of 2°-〇-allyloxycarbonyl-3°-de(dimethylamino)-6 was purified. −
0-Methyl-3'-[methyl(allyloxycarbonyl 4'-0-(trimethylsilyl))erythromycin A was obtained as a white powder.

'H-NMR (200MHz, CDCl!3
)8 = 0.12(s, 9H, TMS).

1, 38 (s, 3H, 6-CHs).

2, 82 (s, 3) 1. NCHs).

3,04 (s, 3H,6-OCRs).

5.81 = 6.04 (m, 2H, furyl proton) (Note: TMS indicates trimethylsilyl group. The same applies hereinafter.) (3) Compound obtained in (2) above (15 g, 0.01
54 mol> of N,N-dimethylformamide (200 m
Dissolve allyl bromide (6,6t+
tll, 0.077 mol) and 85% potassium hydroxide (1,52 g, 0.0231 mol),
Stirred at °C for 2 hours. The reaction solution was extracted with ethyl acetate,
The organic layer was washed with saturated brine and then dried over anhydrous magnesium sulfate. The ethyl acetate layer was distilled off under reduced pressure, and 17.5 g of the obtained crude product was purified by silica gel column chromatography (inner diameter 4.5 cm x 33 cm, elution solvent: ethyl acetate: n-hexane-1:3), 11.6g
11-〇-aryl-2'-〇-allyloxycarbonyl-3°-de(dimethylamine>-a-O-methyl-3
゛-[methyl(allyloxycarbonyl)amino]-4
"-0-(trimethylsilyl)erythromycin A was obtained as a white foam.

'H-NMR (200MHz, CD(J)3
) δ-0,15(s, 9H, TMS).

0, 83 (t, 3H, 14-CHm).

1, 38(s, 31.6-CHs>.

2, 82 (s, 3H, NCHs).

3, 10 (s, 3H, 6-OCHs).

5.80-6.17 (m, 21. allyl proton) (4
) Compound obtained in (3) above (11.45g, 0.0
11 mol) in N,N-dimethylformamide (100 m
l! ”) and diluted with methyl iodide (7.1 mQ
, 0.113 mol) and 85% potassium hydroxide (1,
68 g, 0.025 mol) and 2
The reaction mixture was stirred for 5 hours at room temperature, then extracted with ethyl acetate, and the organic layer was washed with saturated brine and dried over anhydrous magnesium sulfate. The ethyl acetate layer was distilled off under reduced pressure,
Obtained crude product 11. sg by silica gel column chromatography (elution solvent; acetone:benzene-9
7:3), and the Rf' value was 0.65 by silica gel thin layer chromatography analysis (JR open solvent; benzene:
6.09 g of white foam was obtained from the fraction of acetone-9=1).
0 g), palladium acetate (300 mg, 1.34 mmol), triphenylphosphine (900 mg, 3
．． 43 mmol), triethylamine (2.5 ml!
, 17.94 mmol), 99% formic acid (1.25 ml
1, 32.80 mmol), dioxane (30 ml
l) and water (a mixture of 7 ml was refluxed for 6 hours. Cooled, made basic with aqueous ammonia, extracted with dichloromethane, and washed with saturated brine. The dichloromethane layer was dried over anhydrous magnesium sulfate, and the solvent was removed under reduced pressure. The residue was subjected to silica gel column chromatography (elution solvent: chloroform: methanol: ammonia = 95:5:1) to obtain 3.44 g of a white foamy substance. -60, manufactured by Merck & Co.) Column chromatography [inner diameter 3 cm
43 cm, elution solvent, 1 containing 0.5 M sodium chloride
/15M phosphate buffer (phosphate-potassium:disodium phosphate-9:1): Purified with methanol-33=47, and 954 mg of 3'-de(dimethylamino)-
6,12-di-O-methyl-3'-(methylamine)erythromycin A was obtained as a white foam.

'H-NMR (200MHz, CDCJ3)
δ 0.91 (3H, 14-CHs).

1, 42 (s, 31.6-CHm).

2, 50 (s, 3B, NCHs).

3, 10 (s, 31.66-0CH).

3, 32 (s, 311.3”-OCHs).

3, 47 (s, 31.12-OCHs).

4, 42 (d, 11.1'-H).

4, 93 (dd, 11.1"-H).

5, 58 (dd, 18.13-H) (5 N) Compound obtained in <4) above (830 mg, 1.
11 mmol>, 35% formalin (0.33 mQ,
4.44 mmol), 95% formic acid (0.07 m11
, 2.22 mmol) and ethanol (15 mQ )
The mixture was heated to reflux for 45 minutes. The reaction solution was adjusted to pH 8 with a saturated aqueous sodium hydrogen carbonate solution, and ethanol was distilled off under reduced pressure. A saturated aqueous sodium carbonate solution was added to the residue, extracted with dichloromethane, and then washed with saturated brine. After drying the dichloromethane layer over anhydrous magnesium sulfate, 740 mg of 6.12-di-
O-methylerythromycin A was obtained. This was recrystallized from ethanol to obtain 620 mg of the title compound as colorless prism crystals.

m, p, 126-128℃ and 193-195℃ (remelting) elemental analysis values; (Cs * Htr N O1m
) Calculated value (%): C61.47, N9.39.
N1.84 actual value (%): C61.39, N9.5
3. N1.74M ass (SLMS):
m/e =762(Ml(”)I RV KBrCm
-': 3450, (2760-3040)
.

ax 1735, 1695' H-NMR (200MHz, CD (J'3
) δHO190(t, 38.14-CHI).

1, 32 (d, 31.5--CHi).

1, 41 (s, 3H, 6-CHm).

2, 18 (d, IH, 4”-0H).

2.28(s, 611.N(CIA)!),
'3,09(s, 3H,6-OCHs
).

3, 33(s, 31.33--0Cti>.

3, 46 (s, 31.12-OCRs).

3, 67 (d, IH, 5-H).

4,01 (dq, 1)1.5”-H).

4, 42 (d, IH, 1'-H).

4, 93 (dd, 18.1″-H).

5.55 (dd, 11.13-H) IC-N MR (100,4 MHz, CD (J'
3) S -218,7 (C-9), 175.8 (C
-1).

102,8 (C-1'), 96.2 (C-1")
, 80.5 (C-5).

79.2 (C-12), 78.7 (C-6),
78.4 (C-3>.

77.9 (C-4″), 74.8 (C-13>,
72.6 (C-3").

71,4 (C-2'), 70.9 (C-11)
, 68.7 (C-5').

65, 6 (C-3'), 65.5 (C-5'').

53, 2 (12-OCRs), 50.9 (6-OC
lb).

49, 4 (3”-0CHs), 45.0 (C-2>
, 43.9 (C-8>.

40, 2[N(CHl)! ], 39.0(C-4
), 3g, 9(C-7).

38,7 (C-10), 34.9 (C-2"),
28.5 (C-4').

21,4(5′-CHa), 21.4(3”-CH
m).

21, 2 (C-14>, 19.9 (6-CHs)
.

18,6(5”-CHI), 18.3(8-CH
I).

17,1(12-CHa), 15.9(2-CHs
).

11, 1 (10-CHI), 10.5 (C-15
), 9.0 (4-CHI) Example 2 (1) 2'-〇-allyloxycarbonyl-3'-de(dimethylamino)-6-0-methyl-3 obtained in Example 1 (1) '-[Methyl(oxycarbonyl)aminocoerythromycin A (20 g, 0.022 mol) was dissolved in N,N-dimethylformamide (200 ml!
), and under water cooling, trimethylchlorosilane (11,
6ml/l.

0,091 mol) and triethylamine (15,3 mol, 0
．． 11 mol) and stirred at 0 to 5°C for 3.5 hours. The reaction solution was poured into a saturated aqueous sodium carbonate solution and extracted with ethyl acetate. The ethyl acetate layer was washed with saturated brine, and the ethyl acetate layer was dried over anhydrous magnesium sulfate. The residue obtained by distilling off the solvent under reduced pressure was subjected to silica gel column chromatography (elution solvent: ethyl acetate: n-hexane).
3) to give 17.8 g of 2'-0-allyloxycarbonyl-3'-de(dimethylamino)-6-0.
-Methyl-3'-[methyl(allyloxycarbonyl-
11. 4"-0-bis(trimethylsilyl)erythromycin A was obtained as a white foam.

'H-NMR (200MHz, CD
C &> 3) 8 = 0. 14 (s. 9H. 4”-
TMS).

0, 23 (s. 9H. 11-TMS).

0, 82 (t, 3H. 14-CHI).

2, 83 (s. 3H. NCH*).

3, 18 (s. 3H. 6-OCHm).

5, 81-6.04 (m.2H. allyl proton) (2
) The compound obtained in (1) above (4 g, 3.83 mmol) was dissolved in a mixture of acetic anhydride (40 mQ) and dimethyl sulfoxide (60 mQ) and left at room temperature for 4 days.

The reaction solution was neutralized with a saturated aqueous sodium bicarbonate solution and a saturated aqueous sodium carbonate solution, and extracted with ethyl acetate. The ethyl acetate layer was washed with a saturated aqueous sodium hydrogen solution and saturated brine, dried over anhydrous magnesium sulfate, and the solvent was distilled off under reduced pressure. The residue was purified by silica gel column chromatography (elution solvent: ethyl acetate: n-hexane-1=3) to obtain 2.23 g of pale yellow foam.

Next, 2.23 g of this pale yellow foamy substance was dissolved in tetrahydrofuran (200 mL), tetra-n-butylammonium fluoride (200 mg) was added, and the reaction mixture was stirred at room temperature for 21 hours and made basic with a saturated aqueous sodium carbonate solution. , and extracted with ethyl acetate. The ethyl acetate layer was washed with saturated brine, dried over anhydrous magnesium sulfate, and the solvent was distilled off under reduced pressure. 1.92 g of the residue was subjected to silica gel column chromatography (eluent: ethyl acetate:
n-hexane-2:5 to 1:2), purified with 930
mg of 2°-〇-allyloxycarbonyl-3'-de(
dimethylamino)-6-0-methyl-3'-[methyl(
Allyloxycarbonyl)amino]-12-0-(methylthiomethyl)erythromycin A was obtained as a pale yellow foam.

'H-NMR (200MHz, CDCb)
S = 2.18 (s, 3H, 5-CHs).

2, 80 (s, 3H, NCHs).

3,05(s, 3H,6-OCHs) (3) Above (
The compound obtained in 2) (900 mg, 0.936 mmol), triphenylphosphine (7 mg, 0.027 mmol), palladium acetate (2 mg, 0.009 mmol), triethylamine (0.1 std, 1.0 furo mmol), 99% formic acid (0.07 ml!, 1.
837 mmol), ethanol (10 mM), water (0,
75td) was heated to reflux for 4 hours. The mixture was cooled, made basic with saturated aqueous sodium carbonate solution, and extracted with ethyl acetate. The ethyl acetate layer was washed with saturated brine, dried over anhydrous magnesium sulfate, and the solvent was distilled off under reduced pressure. The obtained crude product (720 mg), 35% formalin (0.3 t
nll, 4.036 mmol), 99% formic acid (0,
06m1+, 1.903 mmol) and ethanol-
, +c (10mM) was heated under reflux for 2 hours. A saturated aqueous sodium carbonate solution was added to the reaction mixture, and the mixture was extracted with dichloromethane and washed with saturated brine. After drying the dichloromethane layer over anhydrous magnesium sulfate, the solvent was distilled off under reduced pressure, and 660 mg of the white foamy substance obtained was subjected to silica gel column chromatography (elution solvent: chloroform:methanol:ammonia 95:5:0.5). t' purified, 540a+g(7) 6-0-fi fL-12
-0-(Methylthiomethyl)erythromycin A was obtained as a white foam. This was further dichloromethane/n-
Recrystallization from hexane gave 336 mg of white powder.

fil-1), 129-131℃ M ass (511f5): m/e-8
08(Ml”)I Rl/KBrcm-1: 353
4, 1737.1722.1697aX'H-NMR (200MHz, CDC423
) delta 0.90 (t, 3H, l4-CHm).

1, 40 (s, 3H, 6-CHm).

2, 17 (s, 3H, 5-CHs).

2, 28 (s, 6H, N (CHm)).

3,06 (s, 3H,6-OCHa).

3,32(s,3H,3"-0CRs) -4,00
(dq, tH, 5''-H).

4, 42 (d, IH, 1'-H).

4, 92 (dd, IH, 1″-■).

4,61(d, 11) and 5.13(d, IH)(O
CR, -5CH,>.

5, 58 (dd, IH, 13-H) “C-NMR (loo, 4MHz, CDC423)
S 219.1 (C-9), 175.8 (C-1)
.

102.9 (C-1'), 96.3 (C-11),
81.1 (C-12>.

80.5 (C-5), 78.8 (C-6), 7
8.4 (C-3>.

78.0 (C-4"), 74.3 (C-13),
72.6 (C-3”).

71.4 and 71.0 (C-11, C-2').

70.0((ji*-5CTo), 68.8(C
-5°).

65.7 and 65.6 (C-5”, C-3’).

50.9 (6-OCR,), 49.5 (3”-〇〇〇m).

45.1 (C-8), 44.3 (C-2).

40, 3[N(CHm)*], 39.1(C-4>
.

39.0 (C-7), 38.5 (C-10>.

34.9 (C-2''), 28.6 (C-4').

21.5(C(4,5'-CH5,3''-CHa).

20,0(6-CH,), 18.7(5″-CH,
).

18,3 (S-CHI), 18.2 (8-CHI)
.

16,0(2-CHs), 14.7(12-CHs)
m).

11,5(10-CHI), 10.5(C-15
).

9.1(4-CH,) Moxibustion'' ヱ and 纱 The compounds of the present invention have strong antibacterial activity, and are more easily transferred into the blood and into various organs (particularly the lungs) than conventional erythromycin derivatives. Are better. Therefore, the compounds of the present invention are
It is useful for the treatment of bacterial infections in animals, especially mammals including humans, particularly humans and livestock (including farm animals). For example, Staphylococcus sp, Streptococcus 9p-, Haemophilus sp0, Branhamella! 5l) 1, Neisseria sp,
, Legionella sp0, Campylobacter "E'-% Peptostrebutococcus sp1, Batateroides sp1
It can be used for the treatment of infections caused by a wide range of bacteria, including , Myphblasma sp-% Ureaplasma sp9, Chlamydia sp. For this purpose, the compounds of the invention can be administered orally or parenterally. The dosage forms include tablets, capsules, powders, draws, ointments, suspensions, layers, injections, etc., and they can be manufactured by conventional formulation techniques. The total daily dose of the compound of the present invention administered to the host in single or divided doses is 0.01 to 50 mg/k.
g body weight, more commonly 0.1-30 mg/kg body weight.

Test Example 1 [In vitro antibacterial activity] Using a susceptible disk medium (manufactured by Eiken Chemical), the in vitro antibacterial activity of each of the compounds of the present invention against various test bacterial numbers was measured according to the MIC measurement method of the Japanese Society of Scientific Therapy. .

Erythromycin A and 6-0-methylerythromycin A were used as comparative drugs.

The results are calculated using the MIC value (minimum inhibitory concentration for microbial growth mcg/
mQ ) and shown in Tables 1 and 2.

Table 1 In vitro antibacterial activity MIC value (rv-g/ni
l) (Note) a: 6.12-di-O-methylerythromycin AA:
Erythromycin A B: 6-0-methylerythromycin A Table 2 In vitro antibacterial activity MIC value (IIIcg/mQ) (Note) b: 6-0-methyl-12-0-(methylthiomethyl)
Erythromycin A A: Erythromycin A Test Example 2 [Concentration in plasma and lung tissue] 6-0-methylerythromycin A was used as a comparison drug, and the compound obtained in Example 1 was used as a test sample.

Before administration - male rats (3 and 4 in each group) who had been fasted the night were given 20a+g/g of the specimen suspended in 5% gum arabic.
It was administered orally at a dose of kg. Thereafter, the animals were exsanguinated to death at predetermined intervals, and plasma was collected and used as a measurement sample. On the other hand, immediately after death, the lungs were removed, homogenized with 1750 M phosphate buffer (pH 7,4)/methanol (1:4 V/V), centrifuged at 3.0 OOrpm, and the resulting supernatant was This was used as a measurement sample.

The drug concentration in each sample was measured by an antibacterial activity method using Micrococcus luteus ATCC9341 as the test bacterium and Heart Infujimin agar as the measurement medium.

The results are shown in Table 3.

Table 3 Plasma and lung tissue white concentration (Note) a: 6.12-di-O-methylerythromycin AA:
Erythromycin A B: 6-0-methylerythromycin AN, D: Below detection limit

Claims (1)

[Claims] (1) 6,12-di-O-methylerythromycin A and 6-O-methyl-12-O-(methylthiomethyl)
Erythromycin A and pharmaceutically acceptable salts thereof.