Photolabile drugs

Teroka et al. [88] investigated the effect of grinding on the photostability of tablets incorporating the a- and jS-forms of the photolabile drug, nicardipine. 

Tonnesen HH, Karlsen J. Studies on curcumin and curcuminoids. XL Stabilization of photolabile drugs in serum samples by addition of curcumin. Int J Pharm 1988 41 75. 

Tonnesen HH. Formulation and stability testing of photolabile drugs. Int J Pharm 2001 225 1-14. 

Drugs whose decomposition rates are influenced by the pH include doxorubicin hydrochloride (47), minoxidil (48), menadione sodium bisulfite (67), metronidazole (68), riboflavin (69), colchicine (70), tetracycline hydrochloride (71), phenobarbital (72), dacarbazine (73), furosemide (74), daunorubicin hydrochloride (75), and demeclo-cycline hydrochloride (76). Figures 3 to 6 illustrate how the pH of the solution can influence the degradation rate of some of the reported photolabile drugs. 

Additives incorporated into solutions of photolabile drugs can adversely or favorably affect the photostability of the drug. Heavy metal ions, particularly those possessing two or more valence states with a suitable oxidation-reduction potential between them, e.g., copper, iron, and nickel, can catalyze oxidative decomposition. Their effect is to increase the rate of formation of free radicals. 

In addition to selecting the appropriate solvent system, pH, buffer species and then concentration, ionic strength, dielectric constant, type of container, and storage temperature, the following techniques may be used to enhance the photostability of photolabile drugs. 

The lack of photoprotection for the drug product during administration may lead to increased/decreased efficacy or increased toxicity of photolabile drugs. These episodes may be categorized as preventable medication errors, in particular, as wrong administration-technique errors (2). On the other hand, superfluous photoprotection measurements represent an unproductive use of nurses time and a waste of materials. 

The preparation of DRV multicomponent systems of photolabile drugs is achieved by a similar procedure as the one described earlier (Subheading 3.1.3) (17). For this ... 

The approach to dealing with a drug s instability will clearly depend on the nature of the presentation and its mode of use (Tpnnesen and Moore, 1993). Four case histories are presented here that exemplify an approach to identifying, quantifying, and resolving the issues raised by a photolabile drug substance or formulation. 

The formal labeling requirements for photolabile drug substances and drug products are established by national/regional requirements. 

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