Drugs counters

Lynda Searby, Packaging News, 04 September 2008

 

Vast quantities of pharmaceutical tablets and capsules might be packed into blisters, but a sizeable proportion are still filled into bottles - IMA Safe estimates that bottles account for 40% of all solid drug packaging. Essentially, there are two methods of filling tablets and capsules into bottles: mechanical counting and electronic counting.

 

For large volumes and high speeds, mechanical counters are generally considered the best bet. These use either slats or discs to count the tablets and operate at speeds of up to 400 bottles per minute. But such high speeds come at the expense of flexibility – size parts changeover is very difficult and expensive.

 

Those manufacturers looking for flexibility over speed tend to opt for electronic machines, which count products as they freefall in front of an electronic scanner. These systems operate at much lower speeds of, say, 50 bottles per minute, but require few or no change parts.

 

However, most pharmaceutical manufacturers and contract packers don’t want to have to choose between flexibility and speed – they want both. Equipment suppliers have responded with machines that deliver on both counts.

 

Logic TPS (Tooling & Packaging Solutions), for example, has started acting as UK distributor for US equipment manufacturer IPS, whose Procount machine is said to combine the benefits of both counters.

 

It uses the slat counter to pick up and separate the tablets and a laser counting system to check the right amount of tablets has left the slat and gone into the bottle, explains Keith Gooch of Logic TPS. It achieves speeds of 100-200 bottles per minute.

 

The main feature of the Procount is said to be the ease with which changeover and cleaning can be carried out. The patented design allows downtime to be cut by over 50% versus other counters on the market, says IPS.

 

IPS has installed 70 Procount machines in the US and Gooch says he has quoted on several projects in the UK already.

 

Improving accuracy

Another issue with electronic counters, according to Gooch, is that they are not always 100% accurate. To this end, Logic TPS supplies a tare and gross checkweighing system that can be fitted under an electronic counter to guarantee fill accuracy to +/- 20mg.

 

Called the TC8210, the system will pre-weigh and zero a bottle weight before filling and then check the final weight of the count after filling.

 

It’s a double-check for the filler in case of a funnel blockage or a malfunction on the machine, he explains. Particularly on electronic machines, if an air valve malfunctions, it could give an undercount or an overcount. There’s no way of checking this after the tablets have been counted other than an operator checking each individual container.

 

The system is already in use at contract packer QBL, on a line that is filling 90 bottles per minute.

 

IMA Safe has gone one step further and incorporated product control capabilities into its counting machines. The Conta series of counters screens tablets and capsules for shape, colour and integrity and is capable of ensuring that bottles are filled with the right quantity and type of product. It is also claimed to be the only tablet counter on the market to feature single-tablet reject – eliminating full-bottle rejects and the associated rework.

 

Competitor Marchesini believes product control will remain a key focus for innovation in the future. Innovation in tablet counting technology is mainly focused on electronic devices, and in particular on product control, says a company spokesperson. This is certainly the area where we’re likely to see the most improvement in the future.

 

Shift in focus

That said, Marchesini’s R&D work in recent years has concentrated more on reducing the footprint of its electronic counters. Its newly developed Compact counter integrates an electronic counting head and an intermittent motion capper within one enclosure. The company says the system combines ‘the latest counting and capping technology with perfect integration’: a single base frame, a single electrical cabinet and a single HMI.

 

With liquid pharmaceuticals, closing the margin for error is also a key objective for equipment designers, but here, the focus is on process control rather than product control, driven by the burgeoning biopharmaceutical market. This growing market requires new ideas, says Matthias Poslovski of Optima Group Pharma. The highly active materials lead to small filling volumes. At the same time, a tiny amount may represent a massive value. The onus is on the filler, therefore, to make sure every tiny drop is used.

 

In Process Control (IPC), developed by Optima, performs automatic fill checks, and a statistical analysis of filling weights gives a signal to the filler to reduce or increase the dose.

 

Another advantage, says Poslovski, is that random samples are no longer necessary. Previously they had to be done manually which meant product was lost.

 

When filling liquid pharmaceuticals into bottles, the main decisions are the method of filling and the choice between a separate filler and capper or a monobloc.

 

According to Masterfil, part of the Adelphi group, at present, the pharmaceutical industry is showing greater interest in flowmeter technology.

 

The main advantages of flowmeter fillers are that they have no areas where product can collect, therefore they are very clean, changeover time is reduced as cleaning effluent is minimised and with no moving parts, maintenance is reduced, explains the company’s Russell Martin.

 

He adds that optional touchscreen programming and the ability to store up to 100 filling profiles on Masterfil’s systems has greatly increased throughputs. Adelphi Manufacturing also offers equipment for volumetric filling, a method that is suited to filling thicker liquids at higher speeds.

 

It says a trend among contract packers and biopharmaceutical companies towards monobloc machines is driving sales of its Cerberus system. Everyone is looking to achieve a higher output, but in the same space, observes the company’s Dean Willis.

 

Cleaning up

Although the Cerberus occupies less space than a separate filler and capper, he admits it is not the most compact of all the monoblocs on the market, but there’s a reason for this: Some other machines may be half the size of ours, but if you can’t get in to clean them, that’s irrelevant. On our machines everything is spaced so you can get in and clean and they are manufactured to allow for laminar flow. We also seal the top of the machine off from the bottom, as the bottom may be oiled or greased, and this prevents contaminants from getting through to the top.

 

A Kugler monobloc from Optima has just replaced an older machine of a different make at an Austrian contract packer. It is being used to fill a range of products, from syrups to dietary supplements, into a variety of glass and plastic containers.

 

Containers are fed from a turntable into the monobloc and positioned intermittently at a weighing cell where the tare weight of each container is determined. At the filling stage, rotary piston pumps fill the product. The gross weight of the containers is then checked at the second weighing cell, and the control system determines the net filling weight from these two values. Any deviation from the target weight is transmitted to the dosing station to optimise dosing accuracy.

 

Closures are fed from sorting bowls to the packaging process and made available to the closing units in swivelling motions, making it possible to first insert droppers or plugs, then pre-screw caps or insert and pre-screw spray pumps or PP caps. After checking the presence of closures, the system tightens or closes the caps.

 

A number of features ensure the system is flexible enough to accommodate the various containers, closures and products. The operator control unit, combined with servo technology, means format changes can happen at the touch of a button. The linear and modular construction of the system is also said to be advantageous when making size changes.

 

 

WHEN PRECISION IS PARAMOUNT

When filling liquid pharmaceuticals into tiny receptacles such as ampoules and vials, precision is paramount, both from a cost and a patient health perspective.

 

The German-built Rota range, which is sold in the UK by Adelphi, achieves fill accuracy of 0.02%.

 

Two Rota lines – one for vial filling and one for ampoule filling – are in operation at Torbay PMU (Pharmaceutical Manufacturing Unit), a medium-scale supplier of sterile fluids – mainly injectables – to secondary care NHS.

 

When choosing our equipment, we tried to get most of it from one source, explains Phil Bendell, head of production at Torbay PMU. It makes it much easier for spares and for maintenance.

 

Flexibility was also a major consideration – the ampoules PMU produces range from 1ml to 10ml, and the vials from 10ml to 100ml.

 

We wanted interchangeability of the filling pumps and some components on the machines, as producing more than 50 products means we do a lot of changeover. The Rota machines seemed quite straightforward for the operator to change and understand. They were also priced quite reasonably and Adelphi seemed to offer the best service back-up of all the agents we spoke to.

 

Torbay PMU is about to upgrade its current ampoule filling system to an even larger one to cope with increasing demand, and is designing a new facility which will house a new vial filling line.