If you’ve walked down the skincare or cosmetics aisles of any store, chances are that you’ve probably been bombarded with a saturated visual of shelves brimming full of brightly packaged dermatological products of varying shapes and sizes, with little indication of what product would work best for what you need. It might even take some close label-reading to figure out what a product is used for if you’ve never seen it before, but it’s another thing to also understand if the product’s vehicle type is the most beneficial formulation for your skin.
What is a vehicle and why is it important?
A pharmaceutical vehicle is something that carries or holds a medication and makes it easier to use or give to patients. Topical vehicles include ointments, creams, pastes, gels, lotions, and jellies. The type of vehicle is important because, although it does not have medicinal properties, it does affect how the medication can be combined with the vehicle, how much of the medication is absorbed into the skin, and how the skin reacts to the vehicle itself. In this article, we’ll delve into how the skin can benefit from different types of vehicles and how vehicle choice can affect any active ingredients in the formulation.
Which topical vehicle generally works best and why?
This question is challenging to answer as there is no perfect vehicle for all conditions. The following summarizes the most common topical vehicles, their properties, and common uses:
Ointments are semi-solid vehicles that contain very little to no water content and very high oil content. This high oil content creates a greasy, protective effect against moisture loss and dry air. Ointments tend to stay on top of the skin as a result of its low water content, rather than get absorbed quickly like creams. Since ointments have a lower water content than creams, ointments do not require preservatives. Conditions that relate to dry skin and/or medications that require greater drug absorption (eg. corticosteroids for psoriasis and antibiotics for infections) benefit greatly from using an ointment vehicle.
Creams are typically moisturizing mixtures of equal amounts of water and oil. They are easily absorbed into the skin due to their relatively higher water content than ointments, but can evaporate quicker than ointments, which reduces the contact time of a medication in a cream vehicle. Creams also have a short shelf-life, and therefore require preservatives to extend shelf-life. As a result, creams may sometimes cause skin irritation due to these added preservatives. Creams are beneficial for individuals who have dry skin and do not want a greasy residual feeling.
Gels are semi-solid mixtures that liquify upon skin contact and are comprised of both liquid (alcohol and water) and solid (cellulose for thickening/gelling) components. Gels often contain preservatives and are absorbed very quickly into the skin without creating a moisture barrier, so these vehicles are generally not recommended for conditions with dry and/or sensitive skin. However, gels are beneficial for oily skin types as it does not contain oil and will provide adequate hydration. Gels can also be used in hairy areas and tend to be more cosmetically appealing than ointments as they do not leave residue. Some examples include aloe vera gels, which can be used for sunburns for its cooling effect, and diclofenac gels (e.g., Voltaren), which can be used for muscle pain.
Lotions are vehicles that are thinner than creams and ointments due to their higher water content, and do not need the higher oil content found in the other formulations. Lotions can be beneficial in patients with acne-prone skin as they typically do not clog pores, are light-weight, and usually contain little to no oil. Lotions are very easy to apply to larger areas, and are suitable for hairy areas of the skin and near skin folds.
By understanding the differences between these four main types of vehicles, it becomes much easier to figure out which product best suits a particular condition. The next time you walk through the skin care or cosmetics aisles of any store, we hope you are able to find the perfect product that best suits your needs!
Difference between Ointment Cream Paste Gel Lotion Jelly. PharmaEducation. Accessed May 8 2021. https://pharmaeducation.net/difference-between-ointment-cream-paste-gel/
Oakley, A. Topical formulations. DermNet NZ. Updated February 2016. Accessed May 8, 2021. https://dermnetnz.org/topics/topical-formulations/.
Pharmaceutical Vehicles. Harvard Catalyst. Accessed May 8, 2021. https://connects.catalyst.harvard.edu/Profiles/display/Concept/Pharmaceutical%20Vehicles#:~:text=A%20carrier%20or%20inert%20medium,Dictionary%20of%20Pharmacy%2C%201986.
Principles of Skin Therapy: Common types of topical formulations. DermWeb. Accessed May 9, 2021. http://www.dermweb.com/therapy/common.htm