CC1- contamination of medicinal products: preservatives

which type of drugs need to be completely sterile 

• ophthalmic e.g. anti-infectives, anti-inflammatory, lubricants, drugs used to treat manage or diagnose eye diseases 

• parenteral drugs ( drugs administered by injection or infusion )

what type of drug can be non sterile but with few limitation + what are those limitations ?

what are some of the risk factors of sterility

• aqueous have increased risk of bacteria contamination 

what organisms are the most-> least resistant to sterilising agets and processes 

describe the medical relevance of biofilms in terms of sterilisation

they are highly resistant compared to just regular bacteria 

what is bacterial sporulation 

• its a survival strategy when nutrients become exhausted 

• its used by some gram positive bacteria 

• the spores are very resistant to heat, radiation and chemical agents 

• and they can survive for many years 

list the different types of microorganisms/ things that can cause contamination, the common ones 

• bacteria- positive and negative 

• biofilms- clusters of bacteria 

• bacterial spores- very resistant 

• fungi- yeast and moulds 

what are the three rare types of contaminations 

• virus- found in some human or animal derived products 

• protozoa- found in improperly sterilised contact lenses 

• prions-found in blood products or medical equipment after surgery of patients ( very difficult to remove ) 

what are the consequences of microbial contamination 

what are preservatives 

they are substances used to lower the risk of microbial contamination throughout the products shelf life 
they must be integral to the formulation design and and they can t be included to mask poor manufacturing processes 

what are the ideal properties for preservatives 

• broad spectrum 

• rapid antimicrobial action 

• chemically stable 

• compatible with formulation 

• physically undetectable

• cost effective 

what are the two main classes of agents used for preservatives ( oral )

• organic acids e.g. benzoic acid 

• parabens, esters e.g. propyl paraben 

describe organic acids as preservatives 

• they are limited by Ph dependence so they work at pka values up to 4.2 for benzoic acids

• so they are quite effective however their PKa value limits them 

describe parabens as preservatives 

• they are effective preservatives and the overcome Ph dependence as they tend to have a high pka value of around 8-8.5

• but they aren’t very soluble and act quite slowly 

what are some of the positive factors about 

how are preservative tested 

whats another way of testing preservatives aside for the challenge test 

what re the factors that affect the choice of preservative

what’s the most likely contaminating bacteria and fungi in oral products