152
R. Kozakevych et al.
Multicomponent systems, namely, gelatin/chitosan/HEMA (Gel/Chit/HEMA)
and gelatin/chitosan/HEMA composite, cross-linked with mixture of functional
amino- and vinylsilane (Gel/Chit/HEMA/VA) were composed in weight ratio of
polymers 1:1:1.
Then all solutions are left to stand until trapped air bubbles were removed. The
mixtures were poured into a 75 mm petri dish; the dishes were placed in an oven at
70 ◦ C for 4 h.
Loading of Enoxil into the composite films was performed by mixing 0.5 g of
dried films with 3 mL of Enoxil solution (33.0 mg/mL). After impregnation for
24 h, the polymer films were dried at 80 ◦ C for 2 h.
Infrared (FTIR) spectra were collected using a Thermo Nicolet Nexus 450 from
4000 to 500 cm −1 and resolution of 4 cm −1 , using KBr pellets in weight ratio
sample: KBr as 1:20.
The ATR spectra were recorded using spectrometer Bruker (Germany) in the
spectral range of 600–4000 cm −1 with 16 scans per spectrum at a resolution of
4 cm −1 .
Differential scanning calorimetry (DSC) was performed under nitrogen atmosphere in the temperature range from 20 to 450 ◦ C using a NETZSCH DSC 204F1
Phoenix instrument.
The swelling capacity of the composition films was measured at the room
temperature in the distillate water using gravimetric techniques on three replicas.
For this, the hydrogel samples were dried at 70 ◦ C in oven overnight. The drying
procedure was completed upon reaching constant mass loss values.
Then after the samples were immersed in deionized water for 3 days and the wet
weight of each sample was recorded, the percentage of swelling was calculated from
the formula
α = (m−m 0 /m 0 ) × 100%, where m 0 and m are the masses of film before and
after sample swelling.
In vitro Enoxil release test (dissolution test) has been performed according to
the requirements of the State Pharmacopoeia of Ukraine using the rotating basket
method. The distilled water has been used as a dissolution medium; for each
formulation, dissolution test has been conducted on 200 mg of active component
(Enoxil) using 500 mL of dissolution medium. The distance between inside bottom
of dissolution vessel and basket is maintained at 25 ± 2 mm. The release experiment
was performed at 37 ◦ C under stirring rate of 100 r/min. Samples for measurement
of drug release were taken in time intervals (shown in experimental). Samples of
2 mL were taken, and each sampling was followed by addition of 2 mL of fresh
medium into dissolution vessels. Enoxil concentration in aqueous solution was
determined spectrophotometrically. Prior to determination of Enoxil concentration,
samples were filtered.
Different dissolution models (such as Higuchi and Korsmeyer-Peppas) were
applied to active compound release data in order to evaluate release mechanisms and
kinetics. A very frequently used and easy-to-apply model to describe drug release is
the so-called Korsmeyer-Peppas equation or power law:
R. Kozakevych et al.
Multicomponent systems, namely, gelatin/chitosan/HEMA (Gel/Chit/HEMA)
and gelatin/chitosan/HEMA composite, cross-linked with mixture of functional
amino- and vinylsilane (Gel/Chit/HEMA/VA) were composed in weight ratio of
polymers 1:1:1.
Then all solutions are left to stand until trapped air bubbles were removed. The
mixtures were poured into a 75 mm petri dish; the dishes were placed in an oven at
70 ◦ C for 4 h.
Loading of Enoxil into the composite films was performed by mixing 0.5 g of
dried films with 3 mL of Enoxil solution (33.0 mg/mL). After impregnation for
24 h, the polymer films were dried at 80 ◦ C for 2 h.
Infrared (FTIR) spectra were collected using a Thermo Nicolet Nexus 450 from
4000 to 500 cm −1 and resolution of 4 cm −1 , using KBr pellets in weight ratio
sample: KBr as 1:20.
The ATR spectra were recorded using spectrometer Bruker (Germany) in the
spectral range of 600–4000 cm −1 with 16 scans per spectrum at a resolution of
4 cm −1 .
Differential scanning calorimetry (DSC) was performed under nitrogen atmosphere in the temperature range from 20 to 450 ◦ C using a NETZSCH DSC 204F1
Phoenix instrument.
The swelling capacity of the composition films was measured at the room
temperature in the distillate water using gravimetric techniques on three replicas.
For this, the hydrogel samples were dried at 70 ◦ C in oven overnight. The drying
procedure was completed upon reaching constant mass loss values.
Then after the samples were immersed in deionized water for 3 days and the wet
weight of each sample was recorded, the percentage of swelling was calculated from
the formula
α = (m−m 0 /m 0 ) × 100%, where m 0 and m are the masses of film before and
after sample swelling.
In vitro Enoxil release test (dissolution test) has been performed according to
the requirements of the State Pharmacopoeia of Ukraine using the rotating basket
method. The distilled water has been used as a dissolution medium; for each
formulation, dissolution test has been conducted on 200 mg of active component
(Enoxil) using 500 mL of dissolution medium. The distance between inside bottom
of dissolution vessel and basket is maintained at 25 ± 2 mm. The release experiment
was performed at 37 ◦ C under stirring rate of 100 r/min. Samples for measurement
of drug release were taken in time intervals (shown in experimental). Samples of
2 mL were taken, and each sampling was followed by addition of 2 mL of fresh
medium into dissolution vessels. Enoxil concentration in aqueous solution was
determined spectrophotometrically. Prior to determination of Enoxil concentration,
samples were filtered.
Different dissolution models (such as Higuchi and Korsmeyer-Peppas) were
applied to active compound release data in order to evaluate release mechanisms and
kinetics. A very frequently used and easy-to-apply model to describe drug release is
the so-called Korsmeyer-Peppas equation or power law: