Determination of Kinematic Viscosity of Pharmaceutical Excipients – Test Protocol Based on ST204B Automatic Ostwald Kinematic Viscometer
Kinematic viscosity is one of the core indicators of fluid physical properties, widely used in the quality control of materials such as pharmaceutical excipients and pharmaceutical solvents. As an important component of pharmaceutical preparations, the viscosity characteristics of pharmaceutical excipients directly affect the uniformity, stability, and application effect of the preparations. For example, the viscosity of injectable solvents must be strictly controlled to ensure smooth administration, while the viscosity of oral preparation excipients influences drug release rate and bioavailability. Accurate determination of kinematic viscosity is a key link in ensuring pharmaceutical production quality and clinical medication safety.
Experimental Purpose
By measuring the kinematic viscosity value of pharmaceutical excipients, the purity and rheological properties of the materials can be accurately evaluated, providing data support for the optimization of pharmaceutical formulation processes. This test strictly complies with the first method of General Chapter 0633 Viscosity Determination in the 2025 Chinese Pharmacopoeia and USP35 Physical Tests/(911) Viscosity 5649. The ST204B Automatic Ostwald Kinematic Viscometer used is designed and manufactured in accordance with these pharmacopoeial standards, enabling efficient and accurate determination of kinematic viscosity.
Experimental Samples and Instruments
Experimental Samples: Pharmaceutical excipients
Experimental Instruments:
1.ST204B Automatic Ostwald Kinematic Viscometer
2.Auxiliary components such as special cleaning agents and syringes
3.Qualified constant temperature medium (transformer oil or water)
Operating Procedures
1.Connect the instrument power supply, waste discharge pipe, and suction filter pump. Add an appropriate amount of constant temperature medium to the thermostatic bath to meet the heating and temperature control requirements.
2.Select a suitable Ostwald capillary viscometer, fix it on the instrument's dedicated fixture, and calibrate the optical fiber detection sensor to the upper and lower scale lines of the viscometer.
3.Tap the 7-inch color touch screen to enter the "Parameter Setting" interface. Input parameters such as viscometer tube diameter, constant, sample number, set temperature (e.g., 50℃), constant temperature time, and cleaning times. Return to the main interface after completion.
4.Use the sample injection device to draw approximately 10ml of sample and inject it into the viscometer tube, ensuring the sample liquid level meets the detection requirements.
5.Tap the "Channel 1" or "Channel 2" on the main interface. The instrument will automatically start the constant temperature program. After the sample reaches the set temperature and the constant temperature process is completed, it will automatically start timing and detection. Repeat the measurement 3 times as required by the pharmacopoeia.
6.After the experiment, the instrument automatically calculates the average viscosity value. The results can be printed via the built-in micro-printer or exported to a U disk in CSV/Excel format. For continuous detection, the next set of experiments can be started without shutting down the instrument.
Data Analysis and Result Evaluation
The ST204B Automatic Ostwald Kinematic Viscometer was used to test pharmaceutical excipient samples. The error of three repeated measurements was controlled within ±0.01%, meeting the precision requirements of the first method of General Chapter 0633 Viscosity Determination in the 2025 Chinese Pharmacopoeia and USP35 Physical Tests/(911) Viscosity 5649. The results indicate that the sample has stable viscosity characteristics and qualified purity, which can meet the process requirements of pharmaceutical formulation production. The automatic operation of the instrument not only avoids human errors in manual detection but also significantly improves detection efficiency, providing reliable guarantee for quality screening of batch samples.