Formulation in Pharmacy Practice   2nd Edition

OMEPRAZOLE
 
Omeprazole (Losec®) is chemically unstable in acidic conditions and the pellets (enclosed in a capsule shell) are enteric coated.
Losec® MUPS® are a dispersible tablet formulation of omeprazole.  This preparation can provide a suitable liquid dispersion of omeprazole "beads".  However caution is needed when it is administered via small diameter delivery devices.  For example, the dispersed "beads" are large enough to block feeding teats and small bore nasogastric tubes.

If the patient can swallow liquids, the pellets can be mixed with an acidic beverage and the patient instructed to drink the mixture without chewing the pellets.1  For administration via a nasogastric tube, a 14F or larger bore tube is required to allow intact pellets to be flushed through without clogging.2  However, this method has recently been demonstrated to provide poor and highly variable delivery of omeprazole and lansoprazole, and may be time consuming for nursing staff.3
A suspension of omeprazole in sodium bicarbonate solution can be prepared.4,5  Previous administration methods have included the preparation of a slurry (by mixing the pellets with sodium bicarbonate solution) followed by administration with sodium bicarbonate solution to buffer gastric pH.
Omeprazole suspensions in sodium bicarbonate solution have now been shown to raise gastric pH sufficiently without the need for co-administration of large volumes of additional bicarbonate.6

Formula 4,5

Omeprazole suspension 2mg/mL
 
Omeprazole Capsules 20mg  
Sodium Bicarbonate Solution 8.4% 50  mL
 
Method
Empty the contents of the capsules into a mortar and triturate gently with about 10mL of the sodium bicarbonate solution.  A smooth paste will be formed when the enteric coating has dissolved and the drug is dispersed.  Make to volume.
 
Expiry:  15 days under refrigeration.
This is a conservative expiry date.  Studies indicate chemical stability for longer periods but stability under in-use conditions was not assessed.
 
Stability:   14 days at 24°C;  30 days at 5°C.4
 
Storage:  Omeprazole is light sensitive and storage in amber plastic or glass containers is recommended.  A colour change (to orange or black) may occur on exposure to light.6  The suspension can also be stored in plastic syringes.4
 
SHAKE THE BOTTLE  This is important as omeprazole is incompletely dissolved and partly in suspension.5
 

 
NOTES
  1. Patients initiated on this suspension are usually given a "loading dose" of 40mg (20 mL) followed by a second 40mg dose 6 - 8 hours later.  The maintenance dose is usually 20mg (10mL) daily.6

REFERENCES
  1. Elliott, R.  Nasogastric administration of omeprazole.  Aust J Hosp Pharm 1998; 28 (3): 174-6.
  2. Peckman, HJ.  Alternative method for administering proton pump inhibitors through nasogastric tubes.
    Am J Health-Syst Pharm 1999; 56: 1020.
  3. Dunn A, White CM, Reddy P, Quercia RA, Chow MSS.  Delivery of omeprazole and lansoprazole granules through nasogastric tube in vitro.  Am J Health-Syst Pharm 1999; 56: 2237-30.
  4. Quercia RA, Chengde F, Xinchun Liu, Chow MSS.  Stability of omeprazole in an extemporaneously prepared oral liquid.  Am J Health-Syst Pharm 1997; 54: 1833-6.
  5. Phillips JO, Metzler MH, Johnson K.  The stability of simplified omeprazole suspension (SOS).
    Crit Care Med 1998; 26 (1) Suppl: A101.
  6. Phillips JO, Metzler MH, Palmieri TL et al.  A prospective study of simplified omeprazole suspension for the prophylaxis of stress related mucosal damage.  Crit Care Med 1996; 24: 1793-800.

 

 
Formulation in Pharmacy Practice
2nd Edition
© 2001 PharmInfoTech
ISBN 0-473-07577-6