In Step 2, you mixed up the value you determined in Step 1 which is correctly 0,276 °C. As a result the amount of NaCl in gramm is 0,141 g in the end. Other than that it's a good video and it helped me a lot to learn and understand tonicity. Cheers, keep up the great work.
Hello, the freezing point of NaCl is -0.576 for a 1% solution. So you can use 1% and 0.576 in your calculations. However, 0.9% and 0.52 tends to be used more frequently since 0.9% NaCl solution is isotonic. Hope this helps.
You are required to make a sodium cromoglicate ear drop of 60mL. You are provided with the product formula below BP. Product formula: RX Na cromoglicate 1 %W/V Sodium Chloride q.S Purified water a.d to 60 mL Make isotonic solution. Sig. use in the eye Assuming sodium cromoglicate dissociated by 80% and its Zions compound, Sodium chloride has the dissociation factor, i of 1.8 (RMM of Cromoglicate is 172 and for sodium chloride is 58.5) Isotonicity value of NaCl is 0.9%w/v Instructions: Calculate the quantities of the above ingredients and develop your working formula
Hi there! thank you very much for your video. It has really helped me with my question... HOWEVER, I've encountered a question which gives me the information of BOTH freezing points of a 1% nacl solution as well as an isotonic question. I'm following every step you have said in the video and I assumed that I ignore the 1% nacl information as it was only added to confuse me. Would you agree? thanks!! (If you're interested, the question is below): you are required to make a 50ml dose of a morphine sulfate 2% solution isotonic. 1% w/v morphine sulfate solution freezes at -0.08oC while 1% w/v sodium chloride solution freezes at -0.576oC and isotonic solution freezes at -0.52oC What is the mass of sodium chloride in mg required to make a 50ml dose of morphine sulfate 2% solution isotonic?
You can use either the 1% w/v and -0.576oC or 0.9% and -0.52oC information for the calculation. So you can ignore the 1% nacl information provided if you used the 0.9% and -0.52oC information for your calculations. I hope this helps.
hello thank you sir for very clear explanation. i d like to ask question but i couldnt understand your e mail spelling so i will ask my question here the dr. in the class gave us question which asks: in which concentration procaine HCl will be isotonic? and her answer was 0.52= x.0.122 = % 4.26 i couldn t understand this will please help me sir? thank you so much
1. It is important to recall that the freezing point depression for an isotonic solutions (e.g., plasma) is 0.52. 2. Now, you will find from tables that the freezing point depression for procaine HCl is 0.122. However, this value of 0.122 is for procaine HCl with a concentration of 1% 3. So to determine the concentration of procaine HCl that will be isotonic you can set up a proportion as follows: ( 1%)/0.122=( y)/0.52; where y is the unknown therefore, y = (0.52 x 1%)/0.122 y = 4.26%
We know 0.9% of NaCl is isotonic because it has the same osmolarity as bodily fluids. You can verify this using the osmolarity equation. However, it is generally known that 0.9% of NaCl is isotonic and you can find this information in reference books. Hope this helps. Let me know if you have additional questions.
Hi pharmaceutical calculations, I was wondering whether you please have an email I could email you on regarding some calculation questions. I have some topics I don’t understand at university but I’m unsure what the corresponding videos are on your channel. If I send you the questions would you please be able to direct me towards the correct videos/video titles as I’m finding your channel really helpful. Many thanks
Hello Nayla, you may email questions to profmdanquah@rxcalculations.com . Also, check www.rxcalculations.com/video-tutorials/ for most of the videos. Let me know if there are other topics you would like covered as well.
Yes. The 100 mL comes from the definition of percentage strength (%). See the percentage concentrations calculations video (ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-rThjXRh7Qtg.html) for further clarity if needed. Hope this helps. Let me know if you have additional questions.
Thank you Humanic Genes for watching and for the comment. You could also use the 0.009 in step 3 instead of the 0.9%. When using that approach, then in step 4 you would multiply the answer obtained in step 3 by the volume and not do the proportion at all. Hope this helps.
