Method of measuring the concentration of a glycosaminoglycan anticoagulant

1. A method of cleaning a unit of manufacturing equipment used in the preparation of heparin to obtain an acceptable residual concentration of heparin comprising:

(a) subjecting the unit of manufacturing equipment to a cleaning protocol;

(b) obtaining the absorbance of a sample obtained from the manufacturing equipment comprising:

(i) collecting a sample from the manufacturing equipment;

(ii) reacting the sample with 1,9-dimethyl-methylene blue; and

(iii) determining the absorbance of the sample reacted with 1,9 dimethyl methylene blue;

(c) determining the concentration of heparin in the sample obtained from the manufacturing equipment by comparing its absorbance with the absorbances of a plurality of samples of control heparin in aqueous solutions of known concentrations; and

(d) optionally repeating steps (a)-(c) until the concentration of heparin in the sample obtained from the manufacturing equipment is less than an acceptable residual concentration of heparin.

2. The method of claim 1 , wherein in step (c) the absorbance of the heparin sample is compared to a standard curve of absorbances obtained from a plurality of samples having known concentrations of the heparin.

3. The method of claim 2 , wherein the standard curve of absorbances of samples having known concentrations of the heparin is obtained by a process comprising:

(a) preparing a plurality of samples of known heparin concentration;

(b) reacting the samples of known heparin concentration with 1,9-dimethyl-methylene blue;

(c) determining the absorbance of the samples of known heparin concentration reacted with 1,9 dimethyl-methylene blue; and

(d) graphing the absorbances obtained in step (c) versus the known heparin concentrations of the corresponding samples.

4. The method of claim 1 , wherein a plurality of samples are obtained from the manufacturing equipment.

5. The method of claim 4 , wherein the plurality of samples obtained from the unit of manufacturing equipment are obtained from the surface of one or more of a holding container, a mixing container, a reaction container, a low flow conduit, a high flow conduit, and a dispensing device.

6. The method of claim 1 , wherein the absorbances of the sample and the samples of known concentration are determined in a microtiter plate or a cuvette.

7. The method of claim 1 , wherein the sample from the manufacturing equipment is obtained by swabbing, scrubbing, rinsing, scraping or wiping a surface of the unit of manufacturing equipment.

8. The method of claim 1 , wherein the acceptable residual concentration of heparin is less than about 7.8 micrograms per square inch of surface area.

9. The method of claim 1 , wherein the acceptable residual concentration of heparin is less than about 1.0 micrograms per milliliter of sample.

10. The method of claim 1 , wherein the acceptable residual concentration of heparin is less than about 1.8 micrograms per milliliter of sample.