Application Case of High-Shear Laboratory Emulsifier
In the fields of fine chemical, pharmaceutical, and cosmetic R&D, laboratory-scale emulsification processing is a core link that directly affects formula development, product performance verification, and small-batch trial production. A laboratory engaged in the R&D and small-batch trial production of multi-component semi-solid products once faced persistent challenges in the emulsification process, which restricted the efficiency of formula iteration and the reliability of trial production results. After introducing a high-shear laboratory emulsifier, the laboratory successfully resolved these issues, achieving significant improvements in R&D efficiency, product stability, and batch consistency.
Background and Existing Challenges
The laboratory mainly undertakes the R&D of semi-solid products such as pharmaceutical emulsions, cosmetic lotions, and fine chemical additives, as well as small-batch trial production tasks (5-50 liters per batch). Prior to the equipment upgrade, the laboratory relied on a traditional small-scale magnetic stirrer and a basic homogenizer to complete the emulsification process. Due to the limitations of equipment performance and structural design, the following prominent problems existed in daily work:
- Insufficient shear force and uneven emulsification: The traditional magnetic stirrer could only achieve basic mixing, and the shear force provided by the basic homogenizer was limited (maximum shear rate ≤ 20,000 s⁻¹). For materials containing fine solid particles (initial particle size 3-10 μm) and immiscible oil-water phases, it was difficult to break down agglomerates and achieve complete emulsification. The finished sample often had uneven texture, and the average particle size of the dispersed phase was only controlled at 4-8 μm, which failed to meet the performance requirements of high-end product formulas.
- Poor batch reproducibility of samples: The traditional equipment lacked precise control over key parameters such as shear speed, emulsification time, and temperature. The operating parameters were mainly adjusted manually based on experience, leading to large differences in parameter settings between different operators and even between batches of the same formula. The coefficient of variation (CV) of key indicators (particle size distribution, viscosity, stability) between batches reached 15-20%, which seriously affected the reliability of R&D data and the consistency of trial production products.
- Long formula development cycle: Due to the unsatisfactory emulsification effect, the laboratory needed to repeatedly adjust the formula ratio and processing parameters for each new product R&D project. On average, it took 45-60 days to complete a formula from initial development to stable verification. In addition, the poor emulsification stability of samples led to frequent rework of experiments, further extending the R&D cycle and increasing the consumption of raw materials.
- Risk of sample contamination and difficult cleaning: The traditional homogenizer had a complex structure with multiple dead corners in the mixing cavity and connecting parts. It was difficult to thoroughly clean after each experiment, and residual materials from previous samples were likely to contaminate subsequent experiments. This was particularly critical for pharmaceutical and cosmetic R&D, as even trace contamination could lead to the failure of the entire experiment and affect the safety evaluation of products.
- Unable to match pilot-scale production needs: The performance parameters of traditional laboratory equipment were quite different from those of industrial-scale high-shear emulsifiers. The process parameters verified in the laboratory could not be directly scaled up to pilot-scale production, requiring repeated adjustment and verification during the scale-up process. This not only increased the workload of R&D personnel but also led to the inconsistency between laboratory results and industrial production effects.
Equipment Selection and Core Configuration
To solve the above problems, the laboratory selected a high-shear laboratory emulsifier with precise parameter control, compact structure, and good scalability, which was specially designed for small-batch R&D and trial production. The core configuration and technical characteristics of the equipment are as follows:
1. Core Shear System
The emulsifier adopts a three-stage stator-rotor structure with a detachable design, and the shear gap can be adjusted between 0.05-0.15 mm. The rotor speed is controlled by frequency conversion and can be steplessly adjusted within the range of 3,000-20,000 rpm, generating a maximum shear rate of 85,000 s⁻¹. This structure can effectively break down fine agglomerates and realize rapid fusion of immiscible phases, ensuring the fineness and uniformity of the dispersed phase. The stator and rotor are made of 316L stainless steel with mirror polishing treatment (surface roughness Ra ≤ 0.4 μm), which is corrosion-resistant and easy to clean.
2. Precise Parameter Control System
The equipment is equipped with an intelligent PLC control system and a touch screen operation interface, which can realize precise control of key parameters such as shear speed (accuracy ±10 rpm), emulsification time (accuracy ±1 second), and material temperature (accuracy ±0.5℃). The system supports parameter storage and recall functions, which can store up to 100 sets of formula process parameters. This ensures that the same parameter settings are used for each batch of experiments, avoiding errors caused by manual operation. In addition, the system can automatically record the parameter curve during the emulsification process, providing reliable data support for R&D analysis.
3. Temperature Control and Protection Functions
The mixing cavity is equipped with a jacketed temperature control structure, which can realize heating or cooling of materials through circulating water or oil. The temperature control range is 0-100℃, which can meet the temperature requirements of different materials (especially heat-sensitive materials such as proteins and plant extracts). The equipment is also equipped with over-temperature, over-speed, and overload protection functions. When the parameters exceed the set range, the equipment will automatically shut down to avoid equipment damage and sample deterioration.
4. Compact Structure and Easy Operation
The overall volume of the equipment is compact (length × width × height = 600 mm × 450 mm × 800 mm), which is suitable for the limited space of the laboratory. The mixing head adopts a lifting structure, which can be easily adjusted up and down to adapt to different sizes of beakers and tanks (500 mL-50 L). The detachable design of the stator and rotor facilitates disassembly, cleaning, and replacement, and the entire cleaning process can be completed within 10 minutes, effectively reducing the risk of sample contamination.
5. Scalability for Scale-Up Production
The equipment adopts a modular design, and its core technical parameters (shear rate, speed range, emulsification efficiency) are consistent with those of industrial-scale high-shear emulsifiers. The process parameters verified in the laboratory can be directly scaled up to pilot-scale and industrial-scale production by adjusting the volume ratio, avoiding repeated parameter verification and improving the efficiency of technology conversion.
Implementation Process and Parameter Optimization
After the equipment was put into use, the laboratory carried out a 3-month trial operation and parameter optimization, and adjusted the original emulsification process according to the performance characteristics of the high-shear laboratory emulsifier. The specific implementation process is as follows:
1. Preliminary Experiment and Parameter Calibration
First, the laboratory selected 5 typical formulas (including pharmaceutical emulsions, cosmetic lotions, and chemical additives) for preliminary experiments. By adjusting the shear speed (5,000-18,000 rpm), emulsification time (5-30 minutes), and temperature (25-70℃), the optimal parameter combination for each formula was determined. For example, for a cosmetic lotion containing solid powder and oil phases, the optimal parameters were determined as: shear speed 12,000 rpm, emulsification time 15 minutes, and temperature 45℃. Under these parameters, the average particle size of the sample was reduced to 1.2 μm, and the emulsification stability was significantly improved.
2. Batch Reproducibility Verification
After determining the optimal parameters for each formula, the laboratory carried out batch reproducibility verification experiments. For each formula, 10 batches of samples were prepared continuously using the stored parameter settings. The results showed that the coefficient of variation (CV) of key indicators such as particle size distribution, viscosity, and stability between batches was reduced from 15-20% to 2-5%, which fully met the requirements of R&D and trial production.
3. Process Optimization and R&D Cycle Shortening
Based on the performance advantages of the high-shear laboratory emulsifier, the laboratory optimized the original R&D process. The traditional "step-by-step mixing + repeated homogenization" process was adjusted to "one-step high-shear emulsification", which reduced the number of experimental steps. At the same time, due to the improved emulsification effect and reproducibility, the number of rework experiments was reduced by 70%. For new product R&D projects, the average development cycle was shortened from 45-60 days to 20-30 days.
4. Scale-Up Production Verification
The laboratory selected 2 mature formulas (a pharmaceutical emulsion and a cosmetic cream) for scale-up production verification. The parameters verified in the laboratory (adjusted according to the volume ratio) were directly applied to the pilot-scale production line (500 L). The results showed that the key indicators of the pilot-scale products were consistent with the laboratory samples, and the qualification rate of the pilot-scale products reached 98%, which was 30% higher than before the equipment upgrade. This effectively solved the problem of inconsistent parameters between laboratory and industrial production.
Application Effects and Data Analysis
After 6 months of formal operation, the high-shear laboratory emulsifier has achieved remarkable results in improving R&D efficiency, product quality, and process scalability. The specific data comparison before and after the equipment upgrade is as follows:
1. Significant Improvement in Emulsification Quality
The average particle size of the dispersed phase in the sample was reduced from 4-8 μm to 0.8-2.0 μm, and the polydispersity index (PDI) was controlled below 0.18. The emulsification stability of the sample was greatly improved, and the stratification rate after 30 days of storage was reduced from 10-12% to less than 1%. For heat-sensitive materials, the precise temperature control function of the equipment avoided the loss of active ingredients, and the retention rate of active ingredients was increased by 25-30% compared with the traditional equipment.
2. Remarkable Improvement in Batch Reproducibility
The coefficient of variation (CV) of key indicators between batches was reduced from 15-20% to 2-5%, which ensured the reliability of R&D data and the consistency of trial production products. This not only reduced the consumption of raw materials caused by poor reproducibility (raw material consumption was reduced by 35% on average) but also laid a solid foundation for the subsequent safety evaluation and market promotion of products.
3. Significant Shortening of R&D Cycle
The average R&D cycle for new products was shortened from 45-60 days to 20-30 days, and the efficiency of formula iteration was improved by 40-50%. For improved product formulas, the R&D cycle was shortened from 20-30 days to 7-15 days, which enabled the laboratory to respond more quickly to market demand and improve the competitiveness of R&D results.
4. Reduction of Sample Contamination Risk and Cleaning Workload
The detachable and dead-corner-free design of the equipment, combined with the mirror polishing surface, effectively reduced the risk of sample contamination. The number of experimental failures caused by sample contamination was reduced from 3-4 times per month to 0-1 time per quarter. At the same time, the cleaning time of the equipment was reduced by 60% compared with the traditional equipment, which reduced the workload of laboratory personnel and improved work efficiency.
5. Improvement of Technology Conversion Efficiency
The scalability of the equipment enabled the process parameters verified in the laboratory to be directly scaled up to pilot-scale and industrial-scale production. The time required for technology conversion was reduced from 2-3 months to 2-4 weeks, and the success rate of technology conversion was increased from 65% to 98%. This not only saved the cost of technology conversion but also accelerated the pace of product marketization.
Key Experiences and Operation Notes
During the use of the high-shear laboratory emulsifier, the laboratory summarized the following key experiences and operation notes to ensure the stable operation of the equipment and give full play to its performance:
- Parameter setting should be adjusted according to the characteristics of materials. For high-viscosity materials, the shear speed should be increased gradually (from low speed to high speed) to avoid material splashing and equipment overload; for heat-sensitive materials, the temperature should be strictly controlled, and the emulsification time should be appropriately shortened if necessary.
- The stator and rotor should be cleaned and inspected regularly. After each experiment, the stator and rotor should be disassembled and cleaned thoroughly to avoid residual material contamination. The wear condition of the stator and rotor should be checked every 300 hours of operation, and they should be replaced in time when the wear amount exceeds 0.1 mm to ensure the emulsification effect.
- When carrying out scale-up experiments, the parameter adjustment should be based on the volume ratio and material characteristics, and small-batch pilot experiments should be carried out first to verify the feasibility of parameters before large-scale production.
- The equipment should be calibrated regularly. The speed, temperature, and other parameters of the equipment should be calibrated every 6 months to ensure the accuracy of parameter control and the reliability of experimental data.
- Operators should be trained professionally. Before using the equipment, operators should be familiar with the structure and operation rules of the equipment to avoid operational errors caused by improper operation.
Summary
The application of the high-shear laboratory emulsifier has fundamentally solved the long-standing problems of poor emulsification effect, low batch reproducibility, long R&D cycle, and difficult technology conversion in the laboratory. By virtue of its high shear force, precise parameter control, easy cleaning, and good scalability, the equipment has significantly improved the efficiency of R&D and trial production, ensured the quality and stability of samples, and reduced the consumption of raw materials and experimental costs.
For laboratories engaged in the R&D and small-batch trial production of multi-component semi-solid products, the high-shear laboratory emulsifier is an indispensable core equipment. It not only provides reliable technical support for formula development and performance verification but also bridges the gap between laboratory R&D and industrial production, promoting the efficient conversion of scientific and technological achievements. Through standardized operation and regular maintenance, the equipment can maintain long-term stable performance, providing continuous support for the sustainable development of laboratory work.
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