N. Skalko et al., LIPOSOMES WITH NIFEDIPINE AND NIFEDIPINE-CYCLODEXTRIN COMPLEX - CALORIMETRICAL AND PLASMA STABILITY COMPARISON, European journal of pharmaceutical sciences, 4(6), 1996, pp. 359-366
Inclusion complexes of nifedipine with 2-hydroxypropyl-beta-cyclodextr
in (HP beta CD) were formed by the spray- and freeze-drying methods. N
ifedipine or its inclusion complexes (Nifedipine-CD complex I and II)
were incorporated into liposomes prepared by the ethanol injection met
hod. The highest entrapment value (77.7% of the starting material) was
achieved for liposomes with N-CD complex II. The interaction of nifed
ipine with lipid bilayers was measured calorimetrically. DPPC liposome
s mixed with nifedipine or N-CD complex II showed a slight shift of th
e transition temperature of DPPC towards lower temperatures compared t
o DPPC liposomes alone or mixed with HP beta CD. However, with nifedip
ine, an additional transition peak was seen at lower temperatures in t
he second and all subsequent scans which could not be detected for the
N-CD complex. Plasma stability studies showed that liposomes containi
ng N-CD complex II are more stable than liposomes containing nifedipin
e. Encapsulation of drug-cyclodextrin complexes into liposomes can inc
rease the entrapment of the lipophilic drug and reduce its release fro
m the carrier.