Stabilization of supersaturated solutions of a lipophilic drug for dermal delivery

Citation
K. Moser et al., Stabilization of supersaturated solutions of a lipophilic drug for dermal delivery, INT J PHARM, 224(1-2), 2001, pp. 169-176
Citations number
22
Categorie Soggetti
Pharmacology & Toxicology
Journal title
INTERNATIONAL JOURNAL OF PHARMACEUTICS
ISSN journal
03785173 → ACNP
Volume
224
Issue
1-2
Year of publication
2001
Pages
169 - 176
Database
ISI
SICI code
0378-5173(20010814)224:1-2<169:SOSSOA>2.0.ZU;2-G
Abstract
The stability of supersaturated solutions of a model lipophilic drug (LA-P, a lavendustin derivative) in propylene glycol-water mixtures prepared usin g the method of mixed cosolvents was investigated. The solutions had a fixe d degree of saturation (DS = 4), but contained different ratios of propylen e glycol-water. The absolute concentrations of LAP in these solutions varie d by approximately a factor of 40, but the solutions at lower concentration s were no more stable than the more concentrated solutions, This shows that stability is primarily a question of the degree of saturation and not of t he absolute drug concentration. Solutions of up to 5 degrees of saturation in 7:3 propylene glycol-water mixture were stable when stored for several h ours; those at higher degrees of saturation recrystallized immediately. Whe n the solutions were stirred, recrystallization occurred more rapidly. The influence of various polymeric additives on the stability of the supersatur ated solutions showed that only sodium carboxymethyl cellulose had a stabil izing effect; however, the solution was very viscous and it is not clear wh ether the stabilizing effect was due to this high viscosity or to a specifi c interaction between drug and polymer. (C) 2001 Elsevier Science B.V. All rights reserved.