Ensuring Uniformity in Powder Blends

by Luke Holcombe

FDA promulgated new regulations controlling the manufacture of dietary supplements in 2009 (21 CFR 111). Coupled with consistent regulatory changes affecting the industry, it has become increasingly important to have exacting controls to ensure uniformity in powder. These controls ensure correct dosing of supplement blends and, with the proper knowledge, will prevent the phenomenon of segregation throughout the life of the product. Such processes include, but are not limited to, requiring data for the assignment of expiration dating, using equipment that has been qualified and maintained appropriately, and establishing specifications on the raw materials and batches that make up the final powdered dietary supplement product. The specifications required for the raw materials and finished products must be confirmed through laboratory testing.

Before going into mass production, all customer-approved formulas should require a small scale-up batch to check for uniformity. Precise blending procedures ensure the product blend is uniform with regard to colors and micronutrients. Due to physical characteristics and chemistry, some ingredients may adhere better to one another without interference from other nutrients. Certain ingredients have been known to break down due to the shear of the blades in the blender, causing heavier ingredients or larger particles to separate. This can create issues with uniformity, taste and mouthfeel of the finished product.

Static charge and humidity can also create challenges during the blending process. Some ingredients are extremely hydroscopic and need to be handled following specific guidelines. Humidity is controlled by following cGMP (current good manufacturing practices) specifications and maintaining desired temperatures within each individual processing room. Statically charged powders add to dusting issues, and the particles tend to find themselves sticking together within the blend causing larger particle size and settling. Static can be controlled by making adjustments through the use of processing aids, blending times and even following a sequence of how ingredients are added to the blenders. It is paramount for the contract manufacturer to have a working knowledge of and experience with specific ingredients and their chemistry, as well as their physical properties and how they interact with a mechanical environment (friction, heat and particle size).

Agglomeration is another process that can aid uniformity. Agglomeration is a highly technical means of forming a quick-dispersing, multifaceted granule while also changing the bulk density of a finished product without diluting the ingredients. To agglomerate some items, a carbohydrate binder is sometimes needed or water is sprayed on and dried off to meet specifications. The best agglomerate adds nothing new to the product, but retains the original moisture range as well as improving the dispersion, uniformity and density of the finished product.

Once powdered dietary supplement products are ready for full-scale production, a Master Batch Record (MBR) is created so the formula is capable of being reproduced each time an order is placed. It should be a standard operating procedure (SOP) that the quality control (QC) department reviews and approves the MBR. Each time an individual batch is manufactured, an exact copy of this document is used by the production department. If the MBR is carefully followed so each critical processing step is executed (such as order of addition, mixing times, etc.) and each in-process specification is met, the uniformity of the batch is assured.

The blended formulations can then be filled into bulk containers or single-serve units that will be shipped to the marketer. The filling process is set up to carefully monitor in-process specifications so product uniformity designed into the batching process is continued. As in the batching process, testing is required for the finished product to assure that it meets uniformity specifications. Only dietary supplement products that meet all testing criteria can be released by the QC department for shipment.

Luke Holcombe is the key account manager with Valentine Enterprises Inc., a contract manufacturer based in Lawrenceville, GA. He can be contacted at (770)995-0661 or [email protected] .