Moisture sorption, compressibility and caking of lactose polymorphs

Y Listiohadi, J A Hourigan, R W Sleigh, R J Steele
International Journal of Pharmaceutics 2008 July 9, 359 (1): 123-34
The aim of this study was to conduct storage studies on the moisture sorption and caking properties of lactose powder containing different polymorphs (i.e. alpha-monohydrate, alpha-anhydrous unstable, alpha-anhydrous stable, beta-anhydrous) and spray-dried lactose. The dry sample was compacted using a texture analyzer in paper cylinders and stored at relative humidity (RH) of 33%, 43%, 57% and 75% (25 degrees C, for 3 months). The samples were monitored for weight gain, moisture content, alpha/beta balance and hardness. A simple new method of powder compression for measuring the degree of hardness of caked lactose was developed using a texture analyzer. Clear distinctions were found in the storage behavior of the five different samples. Storage at various RHs caused severe caking to beta-lactose anhydrous and spray-dried lactose. The beta-lactose anhydrous was hygroscopic at 75% RH. The spray-dried lactose, which contained some amorphous lactose, was hygroscopic at all RHs studied. Its moisture sorption behavior differed from that of its major component, alpha-lactose monohydrate, by initially absorbing moisture then desorbing. alpha-Lactose monohydrate was less hygroscopic at 75% RH and it formed friable cakes. The alpha-lactose anhydrous stable was hygroscopic at 75% RH and initially formed hard cakes which became friable during storage. The unstable form of anhydrous alpha-lactose was hygroscopic at all levels of RH studied but did not cake.

Full Text Links

Find Full Text Links for this Article


You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read

Save your favorite articles in one place with a free QxMD account.


Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"