Photolytic Degradation and Its Prevention : Pharmaguideline

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Photolytic Degradation and Its Prevention

Photolytic Degradation is defined as any change or alteration on the main chemical constituent of a drug, food, paints, dyes, inks, pesticides, etc.,
Photolytic Degradation is defined as any change or alteration on the main chemical constituent of a drug, food, paints, dyes, inks, pesticides, etc., due to light or Photon particles. The term photolytic Degradation is coined due to the action of Sunlight and air on a product, causing both oxidation and hydrolysis. In the article, we will be introduced to different factors causing photolytic Degradation. Furthermore, the various consequences of photolytic degradation will be recognized. The article also explains the mechanism of photolytic Degradation. Besides, you will know the different methods by which you can protect a chemical from being degraded due to light and photon particles.

Factors Causing Photolytic Degradation

There are certain factors that are responsible for photolytic Degradation. These factors are essential to determine the degradation rate due to light.

This factor includes:
1. Introduced of Carbonyl group into the chemical constituent of the compound.
2. Introduction of any unsaturated Bond in the chemical constituent of the compound.
3. Use of any catalytic Residue is capable enough to affect the photolytic Degradation
4. Use of solvent catalyst or any additives can easily affect the chemical constituent and photolytic degradation of a compound
5. Introduction of traces of metal such as iron, Nickel or chromium and their oxide can affect the chemical constituent and photolytic degradation of a moiety
6. Use of hydroperoxide prevents the compound from getting degraded from light or Photon particles.
7. Light and Photon particles have a tough time degrading compounds gathered from a dirty or smoggy environment.

Effect of photolytic Degradation

Photolytic degradation Effects both the physical and chemical properties of a compound. The physical changes can be distinguished with naked eyes. The chemical changes are determined by specific tests and observations.

The main effects that are observed in a photolytic degradation include:
1. Photolytic degradation Effect the colour of a chemical moiety.
2. It is capable of affecting the solubility of a compound
3. It can affect the Pka value of the compound
4. It is capable of affecting the order of the compound
5. It can change the viscosity and dissociation constant of a compound

Prevention from photolytic Degradation

Food must be protected from photolytic degradation at all times.

When some nutrients, for example, are exposed to sunshine, they degrade.

In the case of beer, UV light induces the breakdown of bitter hop chemicals to 3-methyl-2-butene-1-thiol, resulting in a change in flavour.

Beer bottles are frequently composed of amber-coloured glass, which has the potential to absorb UV light and so avoid this process. Organic paints, inks, and dyes are more photodegradable than inorganic paints, inks, and dyes. Ceramics are nearly commonly coloured with non-organic origin materials in order for the material to withstand photolytic degradation and retain its colour even under the harshest conditions. Because of the scope of agriculture and the extensive usage of chemicals, the photolytic degradation of pesticides is of major interest.

Pesticides, on the other hand, are chosen in part because they do not photolytic degrade rapidly in the sunshine, allowing them to perform their biocidal function.

To improve pesticide decomposition, additional modalities (e.g., photosensitizers, photocatalysts, and hydroxyl radical-forging reagents) such as hydrogen peroxide are used to form toxic hydroxyl radicals that attack the pesticides.

Pharmaceutical photolytic degradation is of importance since pharmaceuticals are prevalent in many water systems.

Toxicity, endocrine disruption, and genetic damage are all negative consequences on aquatic organisms.

Photolytic degradation of pharmaceuticals must also be avoided in the primary packing material.

Pharmaceuticals are widely protected against UV radiation in this case by amber glasses such as Fiolax amber and Corning 51-L.

A small amount of UV light can pass through the packaging of colloidal silver and iodine (in the form of Lugol's solution) and prevent them from deteriorating.

A common synthetic polymer that can be attacked is polypropylene, in which the tertiary carbon bonds in its chain topology serve as targets.

UV rays combine with these bonds to produce free radicals, which then react with oxygen in the atmosphere to form carbonyl groups in the main chain.

In extreme conditions, surfaces of exposed products may discolour and crack, and the product may disintegrate completely.

Fiber products such as rope used outdoors will have a short product life since abrasion attacks the outer fibers first and they will degrade rapidly.

It is possible to notice a discoloration of the rope as well, indicating an early problem.

UV degradation may also be a problem for polymers with UV-absorbing groups, such as aromatic rings.

Aramid fibres, such as Kevlar, are very UV-sensitive and must be protected from the sun's harmful effects.

The modification of materials caused by light is known as photolytic Degradation. The phrase is commonly applied loosely to the combined action of sunshine and air, which results in oxidation and hydrolysis. In the article, we are introduced to different factors that are responsible for photolytic Degradation. Moreover, we are introduced to the different effects of photolytic Degradation. The article also acknowledges the different preventive measures that will protect a chemical from photolytic degradation.
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Ankur Choudhary is India's first professional pharmaceutical blogger, author and founder of, a widely-read pharmaceutical blog since 2008. Sign-up for the free email updates for your daily dose of pharmaceutical tips.
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