Whether hard shell or soft shell, encapsulation can offer a flexible, functional and speedy dosage form, Paul Davis – a Technical Service Engineer at drug delivery services company Capsugel – told representatives from the drumaking world at the AAPS annual conference in San Diego this week.
But for a manufacturer to ensure the full benefits it is essential to select the correct equipment for the type of formulation and required batch size as getting this wrong could lead to customer complaints and overspending.
There are three main dosing options, Davis explained: Gravity-fed, tamp filling machines (which push pins through a powder bed so that a unit dose is transferred into a dosing disc, then ejected into the capsule body), and dosator-based (which compress the powder to plugs that are transferred into capsules).
“While gravity-fed is good for homogenous blends, it is not good for high moisture products,” he said. Similarly, fluffy formulations do not fit with dosators and “though there is a perception that a tamping machine will suit all powders, this is not always the case and it is not good for high moisture, non-adhesive, and poor-flowing powders, or for sticky formulations.”
Leaving a bitter taste
The extent of selecting the wrong processing equipment was described by Davis using an example from a medium-sized pharma client which had chosen capsules as a dosage form to mask the taste of its API but, despite this, started receiving complaints from users about the capsules tasting bitter.
When Capsugel investigated, it found there were a number of issues with the manufacturing process resulting in high levels of capsules being poorly joined. This in turn meant some of the API was escaping and covering the outside of the capsules and segments of the tamping style machine resulting in API coated capsules and low yields.
“This was caused by the characteristic of the powder and issues with over-filling,” Davis said, and when the problem was solved by using different equipment to form a better slug, “the number of complaints dropped, the yield increased, the speed of the machine increased and the company – which produced more than 100 million capsules annually – saved $780,000.”
Ensuring machinery is evaluated and service regularly can result in similar cost savings, with a mid-size CMO client saving $950,000 on product manufacture after it was diagnosed that its 278 million capsules manufactured per year were being overfilled, and processed in equipment not specialised for dry spongy large particles, and in equipment poorly set up and maintained.
“It is important to ensure machines are as close to new as possible,” said Davis. “In that one case almost $1m a year was saved by not doing anything but ensure they were following the right and most efficient processes.”