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SEM, TEM, and dynamic light scattering techniques where the
average particle size was found out to be lower than 500 nm spherical in shape. Nanosponges dissolved and encapsulated paclitaxel
up to 2 mg/mL [23]. The paclitaxel-loaded nanosponges formed
a water-stable colloidal system avoiding the recrystallization of
paclitaxel. The in vitro release studies showed an almost complete
release in 2 h without initial burst effect. Delivery of paclitaxel via
nanosponges increased the amount of paclitaxel entering cancer
cells and lowered paclitaxel IC 50 , therefore enhancing its pharmacological effect [23]. Cytotoxic efficacy was determined against
MCF-7 cells and paclitaxel nanosponge’s complex was found to be
cytotoxic and more effective against this cell line [25].
After oral administration to rats, paclitaxel-loaded nanosponges
showed a relative oral bioavailability RB% of 256; the area under
the plasma concentration time curve was significantly increased
(approximately threefold) in comparison to the control group
(p < 0.05); the plasma concentration of paclitaxel was determined
using liquid chromatography. These results indicated a promising
new formulation with a safe profile being non-hemolytic and noncytotoxic able to enhance the oral bioavailability of paclitaxel while
avoiding the use of cremophor EL [26].
Camptothecin (CAM), a plant alkaloid isolated from the
Chinese tree Camptotheca, shows a wide spectrum of anticancer
activities. Its therapeutic use is limited by poor aqueous solubility
and rapid inactivation due to the opening of the lactone ring at the
physiological pH yielding the carboxylate form and did not reach
clinical use because of its low solubility, high degradability, and
serious side effects. β-Cyclodextrin nanosponges have been
demonstrated to be able to increase the solubility of lipophilic
compounds, protect them from degradation, and control their
release [27].
In early studies, complexes of CAM with β-cyclodextrin NS are
obtained with different cross-linking ratios (1:2, 1:4, and 1:8 on a
molar basis with the cross-linker). NS formulations of crystalline
and paracrystalline were prepared and characterized. Formulations
protected the lactone ring of CAM after their incubation in physiological conditions at 37 °C for 24 h with 80% w/w of intact lactone ring when compared to only around 20% w/w of plain
CAM. Crystallinity of CAM decreased after loading, zeta potentials were high for stable colloidal nanosuspensions, and F1:4 formulation had the most optimal loading percentage (37%). In vitro
studies indicated a slow and prolonged CAM release over a period
of 24 h. Cytotoxicity studies showed that the CAM formulations
were more cytotoxic than plain CAM on HT-29 cells after 24 h of
incubation [27].
Later, β-cyclodextrin nanosponges were found to overcome
CAM chemical disadvantages and improve the in vitro antitumor
efficacy in the androgen refractory models of prostate cancer
Drug-Encapsulated Cyclodextrin Nanosponges
SEM, TEM, and dynamic light scattering techniques where the
average particle size was found out to be lower than 500 nm spherical in shape. Nanosponges dissolved and encapsulated paclitaxel
up to 2 mg/mL [23]. The paclitaxel-loaded nanosponges formed
a water-stable colloidal system avoiding the recrystallization of
paclitaxel. The in vitro release studies showed an almost complete
release in 2 h without initial burst effect. Delivery of paclitaxel via
nanosponges increased the amount of paclitaxel entering cancer
cells and lowered paclitaxel IC 50 , therefore enhancing its pharmacological effect [23]. Cytotoxic efficacy was determined against
MCF-7 cells and paclitaxel nanosponge’s complex was found to be
cytotoxic and more effective against this cell line [25].
After oral administration to rats, paclitaxel-loaded nanosponges
showed a relative oral bioavailability RB% of 256; the area under
the plasma concentration time curve was significantly increased
(approximately threefold) in comparison to the control group
(p < 0.05); the plasma concentration of paclitaxel was determined
using liquid chromatography. These results indicated a promising
new formulation with a safe profile being non-hemolytic and noncytotoxic able to enhance the oral bioavailability of paclitaxel while
avoiding the use of cremophor EL [26].
Camptothecin (CAM), a plant alkaloid isolated from the
Chinese tree Camptotheca, shows a wide spectrum of anticancer
activities. Its therapeutic use is limited by poor aqueous solubility
and rapid inactivation due to the opening of the lactone ring at the
physiological pH yielding the carboxylate form and did not reach
clinical use because of its low solubility, high degradability, and
serious side effects. β-Cyclodextrin nanosponges have been
demonstrated to be able to increase the solubility of lipophilic
compounds, protect them from degradation, and control their
release [27].
In early studies, complexes of CAM with β-cyclodextrin NS are
obtained with different cross-linking ratios (1:2, 1:4, and 1:8 on a
molar basis with the cross-linker). NS formulations of crystalline
and paracrystalline were prepared and characterized. Formulations
protected the lactone ring of CAM after their incubation in physiological conditions at 37 °C for 24 h with 80% w/w of intact lactone ring when compared to only around 20% w/w of plain
CAM. Crystallinity of CAM decreased after loading, zeta potentials were high for stable colloidal nanosuspensions, and F1:4 formulation had the most optimal loading percentage (37%). In vitro
studies indicated a slow and prolonged CAM release over a period
of 24 h. Cytotoxicity studies showed that the CAM formulations
were more cytotoxic than plain CAM on HT-29 cells after 24 h of
incubation [27].
Later, β-cyclodextrin nanosponges were found to overcome
CAM chemical disadvantages and improve the in vitro antitumor
efficacy in the androgen refractory models of prostate cancer
Drug-Encapsulated Cyclodextrin Nanosponges