1

Medicines in polythene bags: are we treating our patients with respect?

Aree Molyneux, BPharm. MRPharmS

Abstract (To The Article ? I = 125)

The use of resealable polythene bags for supplying medicines is discussed Critically. It is pointed out that problem must arise from the permeability of these bag to water vapour, from their transparency, from there ease of accessibility to children or from their general difficulty of labeling.

Their use is also in contrast with the manufactures packaging. It is suggested that from the viewpoint o professional ethics, pharmacists should insist that It is more appropriate to use brown glass or plastic screw capped mottles and the cost of these should fall with their mass production for this purpose.

  1. Introduction

When I went to my doctor recently for some capsules, I was given them in a re-sealable polythene bag. Indeed, in Thailand we invariably find that doctors and pharmacists supply their medicines in this way. If I was someone who is registered a pharmacist only in Thailand, I should not have found this unusual; but since I am also registered in the UK, and have practised in community pharmacies in London and other areas for many years, I was shocked by this practice. What are the reasons for me being shocked in this way – why are re-sealable polythene bags not be the right way to supply medicines?

2. Permeability to water vapour

In the first place, polythene is surprisingly permeable to water vapour, so that polythene bags are not suitable for packaging moisture–sensitive materials such as medicines, however resistant to liquid water this plastic may be. Recent letter to a chemical journal (1), which reported that chemicals packed in polythene are found to deteriorate from the water vapour permeating through. This phenomenon evidently is not new, for the same letter (1) points out some 50–60 years ago, when polythene was being newly applied as an insulator in transatlantic telephone cables, severe problems were encountered which were traced to its high water permeability to the conducting wires inside. This is why biscuit manufacturers have to use polypropylene rather than polyethylene if they want their products to be crisp when the customer opens the packet.

In hospital pharmacy, polythene bottles used for dispensing liquid medicines have to pass a water vapour permeability test (2).

It should be obvious that this is a phenomenon that must be recognised in a country like Thailand that has such a high ambient humidity. For example, many simple medicines such as aspirin will be readily hydrolysed by such water, with consequent loss of activity and even the formation of reaction products that are deleterious. In the same way, antibiotic capsules are made of gelatin which is water–sensitive, and which will swell when it becomes damp so that the water can then gain access to the active ingredients inside – again with deleterious effects.

  1. Transparency and the effects of light

Another problem with these polythene bags is that they are transparent. Thailand is a country with a sunny climate, so that we must expect the medicines that are supplied to the public to be subject to sunlight. But again, many medicines are light-sensitive, and will lose their activity when exposed to light, and again may also be converted to products that are actually harmful rather than healing.

  1. Child-resistance

The ease of opening of these bags also makes them an attraction to children, who are tempted to eat the contents because they look like sweets. It is not clear whether there are any statistics for poisoning of children in Thailand from such incidents; however, in the UK (which may be taken to be comparable since it has about the same size of population), it has been estimated (3) that the introduction of child-resistant blister-packs has lead to a reduction in accidental poisoning incidents (from all causes) involving children from 61,000 (1982) to 41,000 (1998).

  1. Labelling

Another problem is the absence of any proper labelling on these bags, other than some casual handwriting in biro. Going on my own experience of dispensing in the UK, the British National Formulary that is there has a special section on the use of special labels on products, such as to warn the patient against driving when they are they are taking the medicine because it may cause drowsiness (4), Even standard labels, printed from a computer, will have typewritten entries for the patient’s name, the name of the medicine, the date, and the instructions for use. These would be additional to the pre-printed parts of the label with the pharmacy’s name, address and telephone number, and the injunction to “Keep out of the reach of children”.

The absence of such proper labelling leads to problems in cases of overdosing (whether accidental or deliberate); even if the empty container suspected to have contained the drug taken is available, the hospital emergency room staff would not be able to estimate how much medicine had been taken if the original quantity in the container was not indicated. In the same way, in community surveys of patient compliance and surplus medicines in the home, inadequate labelling leads to uncertainties in identifying the medicine as well as in estimating how much of the original quantity had actually been taken by the patient,

  1. Manufacturer’s packaging

This is all in contrast to the way the medicine’s manufacturer packages the product. For the manufacturer is well aware of the factors outlined above, and takes care that their previous efforts to make a pure product with defined activity is not thrown away – so that the product is always supplied in an opaque container which is thicker walled if it is plastic,

  1. Cost of packaging

The alternative to these polythene bags is to use amber bottles either of plastic or glass, as is the practice in the UK. The objection that is raised to this is course cost. However, I am struck by the fact that brown beer bottles are so cheap here that you see the empty one discarded on the beach and the street. The answer to this is that beer bottles are mass produced and recycled – so why isn’t there the will and effort to do the same for brown bottles for medicines?

  1. Professional attitudes

This problems would not be expected to trouble doctors, who have not been trained with a knowledge of drugs and their sensitivity to water and light, and do not have these issues in front of them. But it should trouble pharmacists, where this is their area of speciality. As health professionals has been entrusted to perform their duties in such a way that they always protect the public. The patients can not be expected to know about the effects of water vapour and light on their medicines with which they have been supplied. In a recent Newsletter of the Pharmaceutical Society, the editor reminded us of the Thai saying about mair pooh luk pooh, that is, about the mother crab and her baby crabs that follow her blindly; perhaps this is one case where the pharmacist should be the mair pooh rather that luk pooh, and should lead the way for a change.

8. Action

So what is to be done? Pharmacists should start using amber plastic bottles or glass bottles, which should be labelled as appropriate, for supplying medicines to their patients. Whether the other professions follow their example is another matter, but at least the pharmacist can say that they are leading the way.

References:

(1) Urben, P.G. 2002. Chemistry in Britain, 38 (11), p 18.

(20 Lawanprasert P et al. 2001. Thai Journal of Hospital Pharmacy, 11 (3): 229-39.

(3) Anonymous. 2002. The Pharmaceutical Journal, 269 (30 November), p 767.

(4) British National Formulary, 2002. British Medical Association/Royal Pharmaceutical Society of Great Britain, 44th edition (September), pp 758-770.

(5) Prapanwatana, M. 2002. Royal Thai Pharmaceutical Society Newsletter, 8 (3), p 8.

< Aree Molyneux < File AM01 < Updated 10/11/18::14:02