Process of controlling the impurities of clindamycin hydrochloride

Abstract

The invention provides a process of controlling the impurities of clindamycin hydrochloride, comprising a step of purifying said clindamycin hydrochloride by two-phase high performance liquid chromatography, wherein the chromatographic conditions are as follows: the detection wavelength is 200-220 nm; the column temperature is 20-40° C.; the flow rate is 0.8-1 ml/min; Mobile phase A: 0.025 mol/L potassium dihydrogen phosphate solution; Mobile phase B: Acetonitrile; and gradient elution is performed. The method of controlling impurities of the invention can solve the problem of the interference by excipients and the problem of the separation of many impurities at the same time. It also provides an effective method for setting quality standard of impurities in such a formulation.

Claims

1. A process of controlling the impurities of clindamycin hydrochloride, comprising a step of purifying said clindamycin hydrochloride by two-phase high performance liquid chromatography, wherein the chromatographic conditions are as follows: the detection wavelength is 200-220 nm; the column temperature is 20-40° C., wherein the chromatographic column is filled with octadecylsilane-bonded silica gel (250 mm×4.6 mm, 5 μm); the flow rate is 0.8-1 ml/min; Mobile phase A: 0.025 mol/L potassium dihydrogen phosphate solution; the pH of Mobile phase A is 7.5; Mobile phase B: Acetonitrile; Gradient elution: Gradient elution is performed based on the following gradient conditions: 0-35 min: 10%-25% phase B; 35˜40 min: 10%-25%.fwdarw.30%-45% phase B; 40˜78 min: 30%-45% phase B; 78˜79 min: 30%-45%.fwdarw.10%-25% phase B; 79˜90 min: 10%-25% phase B.

2. The process of controlling the impurities according to claim 1, wherein the column temperature is 30° C.

3. The process of controlling the impurities according to claim 1, wherein the detection wavelength is 210 nm.

4. The process of controlling the impurities according to claim 1, wherein the gradient elution is performed based on the following gradient conditions: 0˜35 min: 21% phase B; 35˜40 min: 35% phase B; 40˜78 min: 35% phase B; 78˜79 min: 21% phase B; 79˜90 min: 21% phase B.

Description

DESCRIPTION OF THE DRAWINGS

(1) The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

(2) FIG. 1 is an experimental diagram of adaptive resolution of impurity system in Chinese Pharmacopoeia, wherein

(3) Green: Lincomycin control solution;

(4) Turquoise: 7-epi-lincomycin control solution;

(5) Blue: Clindamycin compound gel sample for test.

(6) FIG. 2 is an experimental diagram of the adaptive resolution of the impurity System of Example 1, wherein

(7) Black is the raw material of Clindamycin hydrochloride sample for test;

(8) Blue is a compound gel sample for test.

(9) FIG. 3 shows the experimental diagram of adaptive resolution of impurity system in Example 5,

(10) Black: blank excipents;

(11) Blue: lincomycin control;

(12) Red: 7-epi-lincomycin control;

(13) Coffee color: Compound gel for test.

DETAILED DESCRIPTION OF THE INVENTION

(14) The invention discloses a process of controlling the impurities of clindamycin hydrochloride. Those skilled in the art can properly improve the process parameters in view of the contents herein. In particular, it is to be understood that all similar alternatives and modifications are obvious to those skilled in the art and are considered to be included in the present invention. The method of the invention has been described through a preferred embodiment. It is obvious for those skilled in the art that the method and application described herein may be modified or changed and combined to implement and apply the present invention without departing from the contents, spirit, and scope of the invention.

(15) The invention is further described in combination with embodiments below:

EXAMPLE 1

(16) Waters chromatographic column is filled with octadecylsilane-bonded silica gel (250 mm×4.6 mm, 5 μm); the detection wavelength is 210 nm; the column temperature is 30° C.; the flow rate is 0.8 ml/min; Phase A, 0.025 mol/L potassium dihydrogen phosphate solution (adjusting pH to 7.5 with phosphoric acid), Phase B, Acetonitrile.

(17) The flow rate is 1.0 ml/min, the wavelength is 210 nm. Phase A: 0.025 mol/L potassium dihydrogen phosphate solution (adjusting pH to 7.9)-Acetonitrile (78:28). Phase B: 0.025 mol/L potassium dihydrogen phosphate solution (adjusting pH to 2.5 with phosphoric acid)-methanol (19:81).

(18) The gradient elution is as follows:

(19) TABLE-US-00001 Time (min) A % B % 0 100 0 12 100 0 14 0 100 28 0 100 31 100 0 40 100 0

(20) As shown in FIG. 2, what is to be improved: excipient peaks at 4.7 min and 5.3 min interfere with the detection of impurities.

EXAMPLE 2

(21) Chromatographic conditions:

(22) Waters chromatographic column is filled with octadecylsilane-bonded silica gel (250 mm×4.6 mm, 5 μm); the detection wavelength is 210 nm; the column temperature is 30° C.;

(23) the flow rate is 0.8 ml/min; Phase A: 0.025 mol/L potassium dihydrogen phosphate solution (adjusting pH to 7.5 with phosphoric acid), Phase B, Acetonitrile.

(24) The gradient elution is as follows:

(25) TABLE-US-00002 Time (min) A % B % 0 80 20 12 80 20 14 0 100 28 0 100 31 100 0 40 100 0

(26) What is to be improved: Excipients, Lincomycin and 7-epi-lincomycin all have a peak, but the Lincomycin peak is positioned at the gradient peak, it's not at an appropriate position, the peak of excipient interfere with the detection of lincomycin and 7-epi-lincomycin.

EXAMPLE 3

(27) Chromatographic conditions:

(28) Waters chromatographic column is filled with octadecylsilane-bonded silica gel (250 mm×4.6 mm, 5 μm); the detection wavelength is 210 nm; the column temperature is 30° C.; the flow rate is 0.8 ml/min; Phase A: 0.025 mol/L potassium dihydrogen phosphate solution (adjusting pH to 7.5 with phosphoric acid), Phase B, Acetonitrile.

(29) The gradient elution is as follows:

(30) TABLE-US-00003 Time (min) A % B % 0 80 21 12 80 21 14 0 100 28 0 100 31 100 0 40 100 0

(31) What is to be improved: Excipients, lincomycin and 7-epi-lincomycin all have a peak, the peak time is relatively appropriate, the excipient peak does not interfere with the detection of Lincomycin and 7-epi-lincomycin, the two impurities can also be effectively separated. However, the retention time for main peak is not appropriate, which needs to be readjusted.

EXAMPLE 4

(32) Chromatographic conditions:

(33) Waters chromatographic column is filled with octadecylsilane-bonded silica gel (250 mm×4.6 mm, 5 μm); the detection wavelength is 210 nm; the column temperature is 30° C.; the flow rate is 0.8 ml/min; Phase A: 0.025 mol/L potassium dihydrogen phosphate solution (adjusting pH to 7.5 with phosphoric acid), Phase B, Acetonitrile.

(34) The gradient elution is as follows:

(35) TABLE-US-00004 Time (min) Phase A % Phase B % 0 75 25 35 75 25 37 65 30 75 65 30 76 75 25 86 75 25

(36) What is to be improved: when B %=25% is used, the retention time for main peak of Clindamycin hydrochloride is more than 60 min, thus it shows that the proportion of organic phase was too small. Then the organic ratio is adjusted to B %=30%, however, clindamycin hydrochloride still have no peak within 52 min. Therefore, it is necessary to increase the proportion of organic phase.

EXAMPLE 5

(37) Chromatographic conditions:

(38) Waters chromatographic column is filled with octadecylsilane-bonded silica gel (250 mm×4.6 mm, 5 μm); the detection wavelength is 210 nm; the column temperature is 30° C.; the flow rate is 0.8 ml/min; Phase A: 0.025 mol/L potassium dihydrogen phosphate solution (adjusting pH to 7.5 with phosphoric acid), Phase B, Acetonitrile.

(39) The gradient elution is as follows:

(40) TABLE-US-00005 Time (min) Phase A % Phase B % 0 79 21 35 79 21 37 65 35 75 65 35 76 79 21 86 79 21

(41) What is to be improved: it can be seen from FIG. 3 that the peak time of the impurity such as Lincomycin and 7-epi-lincomycin are appropriate, excipient peak does not interfere with impurity detection. From 35 minutes to 37 minutes the gradient rises too fast, and the gradient peak is too steep. Therefore, the time of gradient variation is prolonged, which makes the gradient change smoother. After adjusting the gradient change time to 5 minutes, it is the final gradient method.

(42) The above is only preferable embodiments of the invention, it should be noted that a number of improvements and modifications may be made by those skilled in the art without departing from the principle of the invention, which should also be regarded as falling within the scope of protection of the present invention.