Drug interactions with plastics

In section 8.3.7 we discussed the adsorption of insulin on to glass and plastic materials used in syringes and giving sets. The plastic tubes 

A theoretical treatment to account for the loss of glyceryl trinitrate from solution to plastic containers has been developed, see Box 10.1. 

Some idea of the rate and extent of disappearance of warfarin sodium from PVC infusion bags can be gained from Fig. 10.19. The marked effect of pH is seen. Losses can 

Box 10.1 Adsorption of glyceryl trinitrate onto plastic containers 

Where A = Glyceryl trinitrate in aqueous solution Where 6 = Adsorbed glyceryl trinitrate Where C = Glyceryl trinitrate dissolved in the 

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Admixture incompatibility- Do not mix or dilute with other solutions or drugs in syringe or infusion flask. Diazepam interacts with plastic containers and administration sets, significantly decreasing availability of drug delivered. 

D Arcy PF. 1996. Drug interactions with medicinal plastics. Adv. Drug React. Toxicol. Rev. 15(4) 207-219. 

Anonymous. Drug interactions with medical plastics. Drug Intell Clin Pharm 1983 17(10) 726-31. 

The particular absorber to be used in a given application depends on several factors. One important criterion is whether the absorber will strongly absorb that portion of the ultraviolet spectrum responsible for degradation of the plastic under consideration. Compatibility, volatility, thermal stability, and interactions with other additives and fillers are other items that must be considered. When used in food wrappings, Food and Drug Administration approval must be obtained. While one or more of these considerations may rule out a given stabilizer or influence llie choice of one class over another, the final selection must await the results of extensive accelerated and long-term tests. 

The term plasticity has been used to emphasize the brain s responsiveness and ability to adapt to changing environmental input. The brain creates new brain cell synapses and prunes old ones in response to experience (Greenough et al., 1992 Weiler et al., 1995). Caged animals with limited opportunities for spontaneous activity will not develop as many neuronal interconnections as more free-ranging animals. It is doubtful that the brains of children would be any less responsive to the environment than those of rats. If environmental influences, such as the frequency and quality of communication, can influence brain development, chronic drug exposure should be viewed as potentially dangerous. In addition, the stimulants make children less spontaneous, reducing their interactions with the environment and hence their brain development. 

Since there is a chemical industry that serves a major portion of all industrialized economies, providing in the end synthetic drugs, polymers and plastics, fertilizers, textiles, building materials, paints and coatings, colorants and pigments, elastomers, and so on, there is also a subject, chemical economics, and it is this subject, the economics of the chemical industry, that is the concern of this chapter. Of course, the chemical industry does not exist alone, rather it interacts with many aspects of the global economy. 

Interactions with Closure Systems. Elastomeric and plastic container and closure systems release leachable compounds into the liquid dosage form, such as nitrosamines, monomers, plasticizers, accelerators, antioxidants, and vulcanizing agents [44], Each type of container and closure with different composition and/or design proposed for marketing the drug or physician s samples has to be tested and stability data should be developed. Containers should be stored upright, on their side, and inverted in order to determine if container-closure interactions affect product stability [6,45]. 

Possible priming procedures for available plastic spacers should be studied with respect to stability, toxicity, drug interactions, and impact on patient compliance. 

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