Now, a company claims to have developed a dispensing closure that attaches to the tube and delivers a set volume of ointment, ensuring a reliable, reproducible dose, reports Phil Taylor.
The MetriCap (pictured) has been designed by a South African firm of the same name and is being marketed for a diverse range of applications, including pharmaceuticals, personal and hair care products and epoxy adhesives.
"Squeezing a tube of ointment may sound simple enough but we all know how wrong things can go. Squeeze too hard and the sticky paste spirals out like a snake. We use a small dot and the rest goes down the drain." according to MetriCap.
The closure fits directly on conventional squeezable tubes and consists of three plastic parts, all of which can be manufactured in high volumes through injection moulding. The closure employs a very elegant "charge-rotate-dispense" mechanism which delivers accurate and consistent dosing of just about any semi-solid material.
This involves squeezing the tube to fill a reservoir, rotating the closure to 'nip' off an accurate dose, and then squeezing it once more to dispense the material.
In the pharmaceuticals sector, there are various drugs delivered topically that could benefit from a more sophisticated dosage system. For example, corticosteroids are sold over-the-counter and prescribed for allergic skin conditions such as atopic dermatitis, but are known to cause side effects such as skin thinning if used in excess. A system such as MetriCap could be used to prevent such overdosing.
Similarly, some hormonal drugs are available as topical gels, and require either unit dose packaging (sachets) or metered dose pumps to make sure that overdosing does not occur. MetriCap could expand the packaging options for these products, as well as opening up the possibility of new product categories such as nicotine creams to help smokers quit the habit.