Article 'Tamiflu Suspension Revisited' dans 'International Journal of Pharmaceutical Compounding'

Editorial: Tamiflu Suspension Revisited

It has been announced that Tamiflu capsules will be manufactured to meet current demands; the nation will depend upon pharmacists for compounding the suspension. The company can mass produce many more capsules in a given time period than the suspension.

However, there is some confusion and misunderstanding about what can be compounded when Tamiflu Suspension is prescribed. The following false statements have been heard:

1. You are required to compound it according to the package insert.
    (Fact: It can be compounded in numerous ways.)
2. You must compound it at a certain concentration.
    (Fact: Different concentrations can be compounded according to the needs of the
    physician/patient. One must consider the stability implications if other concentrations are
    compounded)

There is a shortage of some vehicles, so the following formulations are presented here to enable alternatives for compounding based on vehicle availability. Also, the concentration can be adjusted based upon the desires of the physician and patient to make measuring the dose easier. The important key element is that the physician and pharmacist communicate with each other on the concentration being prescribed and compounded for the patient.

Example formulations are as follows:

Using cherry syrup (Humco) or Ora-Sweet SF (Paddock Labs), these formulas are provided by Roche Laboratories and can be found at: http://www.tamiflu.com/hcp/dosing/extprep.aspx. Additional information can be obtained from this website. The first two formulas provide the information from this website for the 15-mg/mL concentration. We have added the 12-mg/mL column.

Stability of the above two formulations:
Refrigeration: Stable for 5 weeks (35 days) when stored in a refrigerator at 2°C to 8°C (36°F to 46°F).
Room Temperature: Stable for five days (5 days) when stored at room temperature (25°C; 77°F).


IJPC STUDY
The following three formulations were published in the International Journal of Pharmaceutical Compounding 2007; 11(2): 162-174 in a peer-reviewed stability study.

Stability of the above three formulations:
Refrigeration: Stable for 90 days when stored in a refrigerator at 2°C to 8°C (36°F to 46°F).
Room Temperature: Stable for 90 days when stored at room temperature (25°C; 77°F).


OTHER VEHICLES
If the vehicles shown above are not available due to shortage in supply, other suitable oral liquid vehicles can be used, but the stability information may not be available. Therefore, the USP General Chapter <795> standard would be to assign a beyond-use date of 14 days for the preparation when stored in a refrigerator.

Other suitable vehicles are available commercially or the following, from the Pharmacists Pharmacopeia 2nd edition, can be used. They are compounded vehicles using routine compounding ingredients.

• Vehicle for Oral Solution USP
• Vehicle for Oral solution, Sugar Free USP
• Vehicle for Oral Suspension
  
  
  General Preparation Procedure for the Above 
• Separate the capsule body and cap carefully and transfer the contents of the required number of TAMIFLU 75-mg Capsules into a clean mortar.
• Triturate the granules to a fine powder.
• Add about one-third of the specified amount of vehicle to the mortar and triturate the powder until a uniform suspension is achieved.
• Transfer the suspension to an amber glass or amber polyethyleneterephthalate bottle that has been properly calibrated for the final volume.
• Add another approximately one-third of the vehicle to the mortar, rinse the pestle and mortar, and transfer the contents into the bottle.
• Repeat the rinsing (Step 5) with the sufficient vehicle, adding it to final volume in the calibrated container.
• Close the bottle using a child-resistant cap.
• Shake well, package, and label.
  
  
  Loyd V. Allen, Jr., PhD, RPh
  Editor-in-Chief