Vitamin B-100 Complex Prolonged-Release Tablets, 50 ct, QC96590 Sale! This item is currently on backorder but you can still purchase it now and we'll ship as soon as more become available. Energy and nervous system support tablet. Prolonged release vitamins slowly release nutrients into the body over an extended period of time. No added sugar, yeast, preservatives, artificial flavors or colors, and gluten-free.