Student Doctor Network Forums > Pharmacy Forums [ PharmD ] > Pharmacy > Can you come up with the answer to this question? Pharmaceutical Calculation PDA View Full Version : Can you come up with the answer to this question? Pharmaceutical Calculation kwakster92809-30-2004, 04:13 PMA 1:750 (w/v) solution of benzalkonium chloride diluted with purified water in a ratio of 3 parts of the benzalkonium solution and 77 parts of purified water is recommended for bladder and urethral irrigation. what is the ratio strength of benzalkonium chloride in the final dilution? is it just me or all of you think this is a bad question. can anyone come up w/ solution? bananaface09-30-2004, 05:32 PMHere is my stab at it... If you dilute it and put 3 parts solution with 77 parts water, you are making it 3/80 as concentrated as before. So 1/750*3/80 should give you your answer of 1/20000 (w/v). chitowngyrl09-30-2004, 05:37 PMA 1:750 (w/v) solution of benzalkonium chloride diluted with purified water in a ratio of 3 parts of the benzalkonium solution and 77 parts of purified water is recommended for bladder and urethral irrigation. what is the ratio strength of benzalkonium chloride in the final dilution? is it just me or all of you think this is a bad question. can anyone come up w/ solution? Is the answer 1:200 (w/v). bananaface09-30-2004, 06:26 PMIs the answer 1:200 (w/v). Originally there was 1 g of benzalkonium chloride per 750 mL of water. (1/750 w/v). A 1/200 w/v solution would be more concentrated, with 1g of benzalkonium chloride per 200mL of water. You would not get a more concentrated solution by diluting, so 1/200 w/v would not make sense as an answer. WilkesRx09-30-2004, 07:17 PMI agree with bananaface for the answer 1:20,000. If you divide 1g by 750ml, you'll find that there is 0.0013333333g of benzalkonium per 1ml of solution. You take 3mL of that solution (0.004g of benz) and add 77mL of water for a final concentration of 0.004g/80ml, which you set equal to 1 g/x(to find the w:v ratio.) hope we helped! Caverject09-30-2004, 07:58 PMI agree with bananaface for the answer 1:20,000. If you divide 1g by 750ml, you'll find that there is 0.0013333333g of benzalkonium per 1ml of solution. You take 3mL of that solution (0.004g of benz) and add 77mL of water for a final concentration of 0.004g/80ml, which you set equal to 1 g/x(to find the w:v ratio.) hope we helped! Hey look!! I found a picture of WilkesRx and Bananaface!!! ;) http://www.finalesimpsons.de/content/fanart/des/frinkfamily.jpg bananaface09-30-2004, 09:37 PMWhen am I getting my lowercase b back? :p WilkesRx10-01-2004, 04:11 AMI could only wish I was as smart as Prof. Frink. Glayvin! ;) :p MountainPharmD08-18-2007, 12:59 PMI am really disappointed that school has started and no one has posted a kinetics question yet. So I thought I would pull one up from the archives to get it started.:laugh::laugh::laugh: sdn197708-18-2007, 09:32 PMI am really disappointed that school has started and no one has posted a kinetics question yet. So I thought I would pull one up from the archives to get it started.:laugh::laugh::laugh: Mountain - you have too much time on your hands!!!!!!:meanie: MountainPharmD08-18-2007, 09:47 PMMountain - you have too much time on your hands!!!!!!:meanie: It was really slow at work today.......sorry. We only did a 110 scripts and I had three techs because we were training one. Very boring....