Using Alligations in the Real World: Re: Hi

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Dear Wrap!

You have been doing these problems in class using the alligation

method. We recently did a lab with them diluting a strong solution

using a weaker solution.

Unlike Dora I have used alligation method till I am blue in the face

making

1. Lugol's solution

2. Schol's solution

3. Dakin's solution

When we had orders for varying concentrations we would use what was on

the shelf to dilute another strong solutio of the same on the shelf so

that we coulduse up what was there and not waste it, rather than star

from scratch with new material.

A History of Lugol's (from memory so

Lugol's solution (also called " Lugol's Iodine " ) was first developed by

the French physician, Lugol, about 1829 or 1830. It is a brown

or amber like fluid made up of 10 parts potassium iodide (KI) to 5

parts iodine to 85 parts of (distilled) water. It is an effective

bactericide and fungicide and was for a long time a common antiseptic.

In chemistry it has laboratory uses separate and apart from

pharmaceutical applications. Lugol's and other iodine solutions lost

popularity during the last half of the 20th century due to combination

of reasons:

1.It is so cheap to make that it cannot compare to newer, antiseptics

with more marketing power.

2.It stains clothes and temporarily stain skin when used topically to

treat a wound.

3. High amount of allergies to iodine have croped up.

YOU may be familiar with Betadine Solution which is a direct outgrowth

of Lugol's.

Schol's Solution:

http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve & db=PubMed & list_uids=1\

6305106 & dopt=Abstract

" One half of the patients with primary Sjogren's syndrome has

extraglandular manifestations, including renal involvement. The most

frequent renal lesion is tubulo-interstitial nephritis, which

manifests clinically as distal tubular acidosis and may result in the

development of osteomalacia. CASE REPORT: In a 29-year-old female

patient, with bilateral nephrolithiasis, the diagnosis of primary

Sjogren's syndrome, tubulo-interstitial nephritis, distal renal

tubular acidosis, and hypokalemia were established. She was treated

for hypokalemia. Two years later she developed bone pains and muscle

weakness, she wasn't able to walk, her proximal muscles and pelvic

bones were painful, with radiological signs of pelvic bones osteopenia

and pubic bones fractures. The diagnosis of osteomalacia was

established and the treatment started with Schol's solution, vitamin D

and calcium. In the following two months, acidosis was corrected, and

the patient started walking. CONCLUSION: In our patient with primary

Sjogren's syndrome and interstitial nephritis, osteomalacia was a

result of the long time decompensate acidosis, so the correction of

acidosis, and the supplementation of vitamin D and calcium were the

integral part of the therapy.

Dakin's Solution

" Highly diluted, neutral antiseptic solution for cleansing wounds.

Consists of sodium hypochlorite (0,45 % to 0,5 %) and boric acid (4

%). Its solvent action on dead cells hastens the separation of dead

from living tissue. The solution is unstable and cannot be stored more

than a few days. Developed during World War I. "

I worked in a hospital with many doctor's who just did not give up on

using older recipes. They would change the concentrations like I

change underwear! So we had to continually make fresh or dilute

yesterday's with weaker solution or water in order not to waste

product. Whle the Dakin's is made with a solid and a liquid, we still

had to dilute it. Also we had to make it very strong and then use the

concentrate to dilute it so it would last longer.

If you are at home and want to do some of your own compounding try this:

http://falcon.tamucc.edu/~eduweb/AppliedConnections/HSScience/chemistry/dakinsol\

..html

Hope this helps someone out there.

Jeanetta

>

> >This is my attempt on trying to solve this problem, someone else

please verify whether I got the right answer or not.

> >

> >I believe the amount of sterile water added is 571ml with 429ml of

70% Dextrose to get 1000ml of 30% Dextrose.

> >

> >Here's my calculations:

> >

> >30%/70% = x/1000ml

> >

> >solve for x, x = 429ml of 70% Dextrose needed.

> >

> >1000ml - 429ml 70% Dextrose = 571ml of sterile water needed.

> >

> >I hope I got the answer right!

> >Tingting

> >

> > Hi

> >

> > Hi can you help me with this problem

> > A prescription calls for 1000ml of 30% Dextrose. Your pharmacy stocks

> > Dextrose as a 70% solution. How much sterile water should you mix with

> > 70% Dextrose to get the final product?

> >

> > 375 ml

> > 571 ml

> > 125 ml

> > 288 ml

> >

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