Determination of Isotonicity by Sodium Chloride – PST05208 Pharmaceutics Theory and Compounding
NTA Level 5 • Semester 2 • PST05208 Determination of Isotonicity by Sodium Chloride Pharmaceutics Theory and Compounding • Source Session/Topic 13 Full source-text version: all educational wording from the extracted learning source is retained; only presenter/tutor metadata and web-layout noise are removed, while formatting is improved for readability. Session 13: Determination of Isotonicity by Sodium Chloride Equivalent Method Total Session Time: 120 minutes + 6 hours of Practices Prerequisites • None Learning Tasks By the end of this session students are expected to be able to: • Give overview of sodium chloride equivalent method • Determine the isotonicity by sodium chloride equivalent method Resources Needed: • Flip charts, marker pens, and masking tape • Black/white board, chalk and whiteboard markers • LCD projector and computer SESSION OVERVIEW Activity/ Step Time Content Method 1 05 Minutes Presentation Introduction, Learning Tasks 45 Minutes Presentation Introduction to Sodium Chloride Equivalent 2 Method Brainstorming 60 Minutes Presentation Determining the Isotonicity by Sodium Chloride 3 Method Demonstration 4 05 Minutes Presentation Key Points 5 05 Minutes Presentation Evaluation 98 SESSION CONTENTS STEP1: Presentation of Session Title and Learning Tasks (5 minutes) READ or ASK students to read the learning tasks and clarify ASK students if they have any questions before continuing STEP 2: Sodium Chloride Equivalent Method (45 minutes) • The Sodium Chloride equivalent method (E) is the amount of sodium which has the same osmotic effect (based on number of particles) as 1g of the drug sample calculation • Percentage of sodium chloride for adjustment to isotonicity = 0.9 – ( % of medicament in solution x sodium chloride equivalent of medicament) • When adjustment is to be made with a substance other than sodium chloride first calculate the required percentage of sodium chloride and then divide this by the sodium chloride equivalent of the chosen adjusting substance • Example o Calculate the percentage of anhydrous dextrose required to render a 1% solution of ephedrine hydrochloride iso – osmotic with body fluid o Sodium chloride equivalent Ephedrine hydrochloride = 0.30 Anhydrous dextrose = 0,18 • Therefore percentage of sodium chloride for adjustment = 0.9 – ( 1 x 0.3) == 0.6 • Equivalent percentage of anhydrous dextrose = 0.6 = 6 0.1 STEP 3: Determining the Isotonicity by Sodium Chloride Equivalent Method (60 minutes) • Calculate the amount of NaCl required to make the following ophthalmic solution isotonic. Rx Atropine Sulfate 2% NaCl qs Aqua. dist. qs. ad. 30 ml M.ft. isotonic solution 99 1. Determine the amount of NaCl to make 30 ml of an isotonic solution 2. Calculate the contribution of atropine sulfate to the NaCl equivalent 3. Determine the amount of NaCl to add to make the solution isotonic by subtracting (2) from (1) Other substances may be used, in addition to or in place of NaCl, to render solutions isotonic. This is done by taking the process one step further and calculating the amount of the substance that is equivalent to the amount of NaCl calculated in step 3. For example, boric acid is often used to adjust isotonicity in ophthalmic solutions because of its buffering and anti-infective properties. If E for boric acid is 0.50, then the amount of boric acid needed to replace the NaCl in step 3 can be calculated: Or or, more simply: Thus, 0.38 g or 380 mg of boric acid would be required to render the previous ophthalmic solution isotonic 100 To determine amount of ingredients required making isotonic solution Activity: Small Group Discussion (20 minutes) DIVIDE students in small manageable groups ASK students to discuss in groups on the following questions • Calculate the percentage of sodium chloride needed to make an injection containing morphine sulphate 1%, hyoscine hydrobromide 0.04% and sodium metabisulphate 0.1% iso – osmotic with blood plasma REFER Students to Pharmaceutical Calculation. 13th Edition by HOWARD C. ANSEL: Chapter 11,for reference ALLOW students to discuss for 20 minutes ALLOW each groups to present for 5 minutes CLARIFY and SUMMARIZE by using the contents below • Sodium chloride equivalent o Ephedrine hydrochloride = 0.30 o Anhydrous dextrose = 0,18 • Therefore percentage of sodium chloride for adjustment: = 0.9 – ( 1 – 0.14) + ( 0.04 x 0.12 ) + ( 0.1 x 0.70 ) = 0.9 – (0.14 + 0.0048 + 0.07) = 0.9 – 0.2148 = 0.6852 = 0.69 • Percentage of sodium chloride for adjustment = 0.69% STEP 4: Key Points (5 minutes) • The Sodium Chloride equivalent method (E) is the amount of sodium which has the same osmotic effect (based on number of particles) as 1g of the drug sample calculation • Percentage of sodium chloride for adjustment to isotonicity = 0.9 – ( % of medicament in solution x sodium chloride equivalent of medicament) 101 • When adjustment is to be made with a substance other than sodium chloride first calculate the required percentage of sodium chloride and then divide this by the sodium chloride equivalent of the chosen adjusting substance STEP 5: Evaluation (5 minutes) • What is sodium chloride equivalent method (E) in determining isotonic? • What is the percentage of sodium chloride for adjustment to isotonicity? STEP 6: Take Home Assignment (15 minutes) Activity: Take home Assignment (15 minutes) ASK each individual student to do the following assignment • Calculate the strength of sodium chloride solution which is iso – osmotic with blood serum and tears ALLOCATE time for students to do the assignment and submit REFER students to recommended references 102 References Ansel, H. C &Stocklosa, M. J. (2001). Pharmaceutical Calculations (11th ed.). Philadelphia, United States: LIPPINCOTT WILLIAMS & WILKINS Ansel, H. C (2010) Pharmaceutical Calculations (13rd ed.). Philadelphia, United States: LIPPINCOTT WILLIAMS & WILKINS Senya, S. S, Mwasha, C.Y, Muyinga, A. M, Amiri,R. I. and Mauga E.A.S.K. (2011) Tanzania Pharmaceutical Handbook (2nd ed.). Dar eS Salaam, Tanzania: School of Pharmaceutical Sciences. Zatz, J.L and Teixeira, M.G. (2005). Pharmaceutical Calculation (4th ed.). New Jersey: John Wiley & Sons, Inc 103 ← Previous TopicNext Topic →View all