Stability can make or break a drug product or supplement. Learn how USP-grade mineral oil can make all the difference in product stability.
If a tablet crumbles before its use-by date or an ointment separates in the tube, consumer health is at risk, and companies can face costly recalls.
Global guidelines define “stability” as the ability of a drug to stay within its quality limits through shelf life.
Keeping every dose stable is the first test of safety—and a big reason brands guard their reputation so closely.
Suzanne Kingsbury, Director of Quality
About USP-Grade Mineral Oil
Mineral oil, often called white oil, comes in many purities. Only one meets the strict limits set by the U.S. Pharmacopeia (USP). To earn the USP label, each batch must:
- Demonstrate purity with no aromatics as measured by sensitive UV absorption.
- Contain no cancer-linked polycyclic aromatic hydrocarbons (PAHs).
- Hit narrow ranges for viscosity, color, and odor.
- Come from facilities working under current Good Manufacturing Practices (cGMP).
In short, USP-grade mineral oil is tested, traced, and trusted—a clear step above tech-grade or cosmetic-grade oils. This standard earns a place for these oils in the National Formulary (NF).
“The USP-NF has for 185 years provided public standards for medicines. These standards provide information on the quality, strength, and purity of the ingredient or product and ensure consistency in the medicines taken by the public. USP feels strongly that the success of any drug importation program implemented in the United States must recognize the critical role of public standards and require adherence to the official US compendia – the USP-NF. Adherence to the public standards in the USP-NF can achieve, via testing to the standards of a monograph and with the use of USP Reference Standards, the assurance that medicines meet the quality expected by patients and practitioners.” – Dr. Todd Cecil, Vice President, USP (testimony before the U.S. Senate)
How USP-Grade Mineral Oil Protects Drug Stability
- Moisture barrier – An inert compound, USP-grade mineral oil creates a thin film on tablets or powders, blocking water vapor that can trigger early breakdown and also functions as dust control.
- Oxygen shield – Its low reactivity keeps air away from sensitive actives.
- Plasticizer in soft-gel shells – Small amounts act as an excipient (inert substance) that keeps gelatin flexible, cutting the risk of cracks during storage; USP excipients are certified with annual independent audits to ensure safety.
- Texture control in creams and ointments – Consistent quality simplifies durable emulsification so the dose spreads evenly every time.
Because the oil itself does not change in normal heat, light, or humidity, it acts like a built-in insurance policy for the formulator.
Real-World Uses of USP-Grade Mineral Oil
These are just a few examples of mineral oil applications in pharmaceuticals and food supplements, for which the highest level of purity is critical.
Eye Ointments — Smooth, Sterile Protection
Pharmacy‐shelf eye lubricants use a USP-grade mineral oil blend to keep the base silky and germ-free. The oil forms a gentle moisture barrier, so delicate eye tissue stays calm instead of drying out.
Soft-Gel Vitamins — Flexible Shells That Don’t Crack
A few drops of mineral oil act as a plasticizer inside gelatin shells, letting them bend without breaking during filling, shipping, and months on a store rack. Softer shells also keep capsules from sticking together in the bottle.
Nasal Sprays — Long-Lasting Moisture Relief
In saline and medicated sprays, USP-grade mineral oil coats nasal passages and slows water loss—as shown in ethical testing on rabbits. That gentle film eases dryness and protects sensitive membranes—especially in arid or cold climates.
Topical Creams & Salves — Even Texture, Every Dose
Many prescription and over-the-counter creams list mineral oil as an inactive ingredient. It keeps the formula smooth so the active drug spreads evenly and delivers the right dose with each squeeze.
Meeting the Rules: A Quick Blueprint
- List it in your stability protocol. Regulators expect every excipient—and its role—named when you file a stability study.
- Use verified supply only. The USP Ingredient Verification Program audits producers and adds an extra mark of quality your QA team can point to.
- Keep lot records handy. Batch-to-batch certificates of analysis (CoAs) prove your specs match the USP monograph and heavy-metal chapters.
PRO TIP: Check the FDA Inactive Ingredient Database to confirm use levels that have already passed review for your route of delivery.
How to Pick a Supplier You Can Trust
- Consistency you can measure – Ask for five consecutive CoAs and look at viscosity variation.
- Audit readiness – Your supply partner should welcome on-site visits and share cGMP certificates.
- Local logistics muscle – North-American storage cuts lead times and reduces port delays—vital when small changes in moisture can ruin a whole lot.
(For deeper questions, see our post “3 Questions for Your White Oil Supplier.”)
What’s Next? Trends to Watch
- Lower-carbon feedstocks – Refiners are trialing renewable or bio-based sources to trim Scope 3 emissions while keeping USP specs.
- Local warehousing & supply-chain resilience – Pharma buyers increasingly favor suppliers with North-American storage and quick-ship capability to dodge port delays and humidity swings that can ruin a batch.
- Tighter impurity targets – USP’s elemental-impurity chapters are under review; limits may tighten again soon.
Staying ahead of these changes—and working with suppliers that do—protects both compliance and brand trust.
Keep Your Products Safe, Simple, and Stable: USP-Grade Mineral Oil from Renkert Oil
Pharmaceutical stability starts with smart excipient choices.
USP-grade mineral oil offers a proven, easy-to-use barrier against the water, oxygen, and handling stress that shorten shelf life.
If you need a steady, North-American source—with full USP verification and expert tech support—Renkert Oil is ready to help.
Talk with a USP-Verified Mineral Oil Specialist →
Let’s work together to produce high-quality medicines and supplements—safely, simply, and cost-effectively.
