264
bioavailability. Hydrophilic polymers have been used in the past for
enhancing the complexation efficiency of β-CD. With a similar
rationale copolyvidonum was used to enhance the complexation
efficiency of a β-CD nanosponge. Three formulations were prepared by solid dispersion technique to incorporate drug in the
nanosponge: two binary systems of drug-nanosponge and
drug- copolyvidonum and one ternary system of drug–nanosponge–copolyvidonum. The solubility was enhanced over 55-fold
in the case of ternary complex and over 27-fold in the case of
binary complex drug-nanosponge. PXRD studies showed maximum amorphousness of the drug in the case of ternary complex.
This can explain the enhanced dissolution and solubility of the itraconazole dispersed in the ternary complex. Thus, the bioavailability of itraconazole can be expected to be more compared to plain
drug [70].
Clotrimazole (CTZ) is a BCS class II drug having a limited
therapeutic potential because of its poor aqueous solubility and
relatively short half-life. Hydroxypropyl β-cyclodextrin (HP-β-CD)
nanosponges were prepared using dimethyl carbonate as a crosslinker and suitably gelled. They have been used to enhance the
solubility and efficacy of CTZ by forming a complex with NSs.
Nine formulations were prepared based on a 3
2
full factorial design
using different Pluronic F-127: Pluronic F-68 ratios, characterized
and assessed for in vitro release, in vitro bioadhesion, in vivo antifungal activity, and in vivo irritation using female Wistar albino
rats. The optimized CTZ-NS in situ gel (F-10) demonstrated prolonged drug release up to 15 h (considerably longer than that of
the conventional in situ gel). The CTZ-NS gel was nonirritant in
vivo and showed higher in vivo antifungal activity and in vitro bioadhesion than did the conventional in situ gel. These results signified the promising applicability of the formulated CTZ-NS gel as a
novel delivery system for the local treatment of vaginal candidiasis
and other similar infections [71].
Quercetin is a flavonoid widely distributed in vegetables and fruits
and exhibits strong antioxidant activity, but the poor solubility and
stability of quercetin limit its function and application. It has been
shown to have a variety of biological activities and pharmacological
actions, such as anti-oxidation, anti-inflammation, anticancer, antiplatelet aggregation, antianemic action, and antianaphylaxis effects.
However, pharmaceutically, quercetin is a challenging molecule to
be delivered due to its poor solubility 7.7 μg/mL in water, <2%
bioavailability in humans, low hydrophilicity with logP value of
1.81, gastrointestinal instability, extensive first-pass metabolism,
and minimal absorption in gastrointestinal track [72]. An improved
oral formulation of quercetin is required for better bioavailability
and higher efficacy of quercetin. Cyclodextrin-based nanosponges
were prepared using diphenyl carbonate for the cross-linking.
2.5 Cyclodextrin
Nanosponges
for Antioxidants
Maria Tannous et al.
bioavailability. Hydrophilic polymers have been used in the past for
enhancing the complexation efficiency of β-CD. With a similar
rationale copolyvidonum was used to enhance the complexation
efficiency of a β-CD nanosponge. Three formulations were prepared by solid dispersion technique to incorporate drug in the
nanosponge: two binary systems of drug-nanosponge and
drug- copolyvidonum and one ternary system of drug–nanosponge–copolyvidonum. The solubility was enhanced over 55-fold
in the case of ternary complex and over 27-fold in the case of
binary complex drug-nanosponge. PXRD studies showed maximum amorphousness of the drug in the case of ternary complex.
This can explain the enhanced dissolution and solubility of the itraconazole dispersed in the ternary complex. Thus, the bioavailability of itraconazole can be expected to be more compared to plain
drug [70].
Clotrimazole (CTZ) is a BCS class II drug having a limited
therapeutic potential because of its poor aqueous solubility and
relatively short half-life. Hydroxypropyl β-cyclodextrin (HP-β-CD)
nanosponges were prepared using dimethyl carbonate as a crosslinker and suitably gelled. They have been used to enhance the
solubility and efficacy of CTZ by forming a complex with NSs.
Nine formulations were prepared based on a 3
2
full factorial design
using different Pluronic F-127: Pluronic F-68 ratios, characterized
and assessed for in vitro release, in vitro bioadhesion, in vivo antifungal activity, and in vivo irritation using female Wistar albino
rats. The optimized CTZ-NS in situ gel (F-10) demonstrated prolonged drug release up to 15 h (considerably longer than that of
the conventional in situ gel). The CTZ-NS gel was nonirritant in
vivo and showed higher in vivo antifungal activity and in vitro bioadhesion than did the conventional in situ gel. These results signified the promising applicability of the formulated CTZ-NS gel as a
novel delivery system for the local treatment of vaginal candidiasis
and other similar infections [71].
Quercetin is a flavonoid widely distributed in vegetables and fruits
and exhibits strong antioxidant activity, but the poor solubility and
stability of quercetin limit its function and application. It has been
shown to have a variety of biological activities and pharmacological
actions, such as anti-oxidation, anti-inflammation, anticancer, antiplatelet aggregation, antianemic action, and antianaphylaxis effects.
However, pharmaceutically, quercetin is a challenging molecule to
be delivered due to its poor solubility 7.7 μg/mL in water, <2%
bioavailability in humans, low hydrophilicity with logP value of
1.81, gastrointestinal instability, extensive first-pass metabolism,
and minimal absorption in gastrointestinal track [72]. An improved
oral formulation of quercetin is required for better bioavailability
and higher efficacy of quercetin. Cyclodextrin-based nanosponges
were prepared using diphenyl carbonate for the cross-linking.
2.5 Cyclodextrin
Nanosponges
for Antioxidants
Maria Tannous et al.