Friday, September 14, 2012

Pediatric Compounding

Today, I spent the day with Dr. Dong, the only compounding pharmacist at the Pediatric Inpatient Pharmacy.  Before beginning the process of compounding, Dr. Dong stressed the importance of consistency.  What it all boiled down to was the fact that uniform medication doses leads to appropriate drug levels in the blood, which leads to efficacy while minimizing toxicity.  The second point of emphasis was sterile technique.  In 1676, Leeuwenhoek discovered the existence of bacteria, which as we know now, is invisible to the naked eye.  In 1881, the concept that bacteria can lead to illness was born and, in 1905, the concept that isolated bacteria can infect differet hosts and cause the same illness was born (Koch's postulates).  All of these microbiological advancements lead to sterile technique, which is the standard of practice for compounding at NTUH.

When compounding, Dr. Dong follows three rules:  1) The drug cannot be wrong 2) the dose cannot be wrong 3) amount of drug dispensed cannot be wrong.  At the same time, he understands that "to err is human."  The attitude that mistakes are embarrassing and should be swept under the rug is the exact attitude that will lead to more errors in the future.  Rather, mistakes should be brought to the forefront and corrected to prevent future errors of the same nature. 

We started out by thoroughly washing our hands with soap and scrubbing every fold/nail/crease.  We then sprayed our hands with 75% alcohol, a concentration that has been shown to effectively penetrate the bacterial cell membrane and cause cells the shrivel.  Once our hands were dry, we put on gloves, hair nets, and carbon face masks.  Dr. Dong explained that the carbon masks are designed to prevent dust inhalation, whereas the surgical masks used elsewhere in the hospital are designed to protect against disease transmission.  The medication we were compounding was Aldactone 3.1 mg/dose.  The standard tablet comes in 25 mg, and therefore, our job was to take 1/8 of each tablet and package them into unit doses packages in powder form.  Since the medication would be administered to children, flavoring would need to be added as well.  For liquid formulations, flavoring agents consist of syrups.  For powder formulations, flavoring is done by adding lactose monohydrate for two reasons:  1) When the disaccharide is broken down to a monosaccharide, it tastes sweet 2) The lactose increases the volume so it is easier to ingest.  The first step was to weigh the appropriate amount of lactose.  Next, we ground up the Aldactone tablets using an automatic grinder, shown below.

Before combining the two powders, we put the Aldactone powder through a sift to ensure all of the particles were of uniform size.  To minimize wasting, we ground the large particles remaining with a mortar and pestle and sifted those particles once again.  At this point, we were ready to combine the lactose and Aldactone.  We first ground up the Aldactone with 1/2 of the preweighed lactose using the mortar and pestle.  The second 1/2 was added subsequently to ensure consistency.  Now that the medication and lactose were combined, the final step was the separate them into 3.1 mg unit packages.  Luckily, NTUH has a Japanese made autmoatic package divider, which, in addition to separating the powder and packaging them, also prints the label so that the product is in its final form.  

 As with any pharmacy practice, the final check had to be done.  Dr. Dong does a "recheck" with every order, meaning he checks his own work.  Afterwards, he has another pharmacist do a "double check" to verify his work.  At NTUH, the standard considered adequate for patients to take is a variance in weight of <6%.  In industry, where everything is automated, the standard is 3-5%.  Our batch of Aldactone 3.1 mg ended up having a variance of <5%!

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