Effect of sodium lauryl sulfate in dissolution media on dissolution of hard gelatin capsule shells.
OBJECTIVE
Sodium lauryl sulfate (SLS) is a commonly used surfactant in dissolution media for poorly water soluble drugs. However, it has occasionally been observed that SLS negatively impacts the dissolution of drug products formulated in gelatin capsules. This study investigated the effect of SLS on the dissolution of hard gelatin capsule shells.


METHODS
The USP paddle method was used with online UV monitoring at 214 nm (peptide bond). Empty size #0 capsule shells were held to the bottom of the dissolution vessel by magnetic three-prong sinkers.


RESULTS
SLS significantly slowed down the dissolution of gelatin shells at pH < 5. Visually, the gelatin shells transformed into some less-soluble precipitate under these conditions. This precipitate was found to contain a higher sulfur content than the gelatin control sample by elemental analysis, indicating that SLS is part of the precipitate. Additionally, the slowdown of capsule shell dissolution was shown to be dependent on the SLS concentration and the ionic strength of the media.


CONCLUSIONS
SLS interacts with gelatin to form a less-soluble precipitate at pH < 5. The use of SLS in dissolution media at acidic pH should be carefully evaluated for gelatin capsule products.
Zhao
Fang
F
Biopharmaceutics R&D, Pharmaceutical Research Institute, Bristol-Myers Squibb Company, One Squibb Drive, P. O. Box 191, New Brunswick, NJ 08903, USA. fang.zhao@bms.com
Malayev
Vyacheslav
V
Rao
Venkatramana
V
Hussain
Munir
M
D002214:Capsules; D005780:Gelatin / Q000737:chemistry* / Q000493:pharmacokinetics*; D009994:Osmolar Concentration; D012967:Sodium Dodecyl Sulfate / Q000737:chemistry* / Q000493:pharmacokinetics*; D012995:Solubility / Q000187:drug effects; D013500:Surface Tension / Q000187:drug effects
D002214:Capsules; D012967:Sodium Dodecyl Sulfate; D005780:Gelatin