Table 1.
Composition of polymeric solutions (in grams).
| Formulation | C940 | PCP | CHL | CHM | PW | AA 1% |
|---|---|---|---|---|---|---|
| C940-0.10 | 0.100 | - | - | - | 99.900 | - |
| C940-0.70 | 0.700 | - | - | - | 99.300 | - |
| C940-1.30 | 1.300 | - | - | - | 98.700 | - |
| PCP-0.200 | - | 0.200 | - | - | 99.800 | - |
| PCP-0.225 | - | 0.225 | - | - | 99.775 | - |
| PCP-0.250 | - | 0.250 | - | - | 99.750 | - |
| PCP-0.300 | - | 0.300 | - | - | 99.700 | - |
| PCP-0.400 | - | 0.400 | - | - | 99.600 | - |
| PCP-0.600 | - | 0.600 | - | - | 99.400 | - |
| PCP-1.000 | - | 1.000 | - | - | 99.000 | - |
| CHL-3000 | - | - | 3.000 | - | - | 97.000 |
| CHL-3.50. | - | - | 3.500 | - | - | 96.500 |
| CHM-200. | - | - | - | 2.000 | - | 98.000 |
| CHM-2.50 | - | - | - | 2.500 | - | 97.500 |
| CHM-30.0 | - | - | - | 3.000 | - | 97.000 |
[i] C940: carbomer 940, PCP: polycarbophil, CHL: chitosan low molecular weight, CHM: chitosan medium molecular weight, PW: purified water, AA 1%: acetic acid water solution 1% (1%)
Table 2.
Process parameters of preparation for individual polymers.
| Polymer | Primary stirring (rpm) | Secondary stirring (rpm) | Homogenization time (min) |
|---|---|---|---|
| Carbomer | 300 | 330 | 30 |
| Polycarbophil | 300 | 350 | 45 |
| Chitosan | 500 | 700 | 45 |
Table 3.
Appearance of polymeric solutions and gels, pH of polymeric solutions, and pH of the gelation.
| Formulation | Appearance | pH | ||
|---|---|---|---|---|
| polymeric solution | gel | polymeric solution | gelation | |
| C940-0.10 | ++ | +++ | 3.57 ± 0.05 | 6.74 ± 0.47 |
| C940-0.70 | ++ | +++ | 2.93 ± 0.10 | 3.01 ± 0.14 |
| C940-1.30 | ++ | +++ | 2.66 ± 0.03 | 2.81 ± 0.02 |
| PCP-0.200 | + | − | 3.68 ± 0.02 | − |
| PCP-0.225 | + | +++ | 3.59 ± 0.05 | 6.61 ± 0.21 |
| PCP-0.250 | + | +++ | 3.56 ± 0.03 | 6.02 ± 0.06 |
| PCP-0.300 | + | +++ | 3.39 ± 0.03 | 5.36 ± 0.30 |
| PCP-0.400 | + | +++ | 3.35 ± 0.04 | 4.19 ± 0.33 |
| PCP-0.600 | + | ++ | 3.26 ± 0.04 | 4.03 ± 0.08 |
| PCP-1.000 | + | + | 3.32 ± 0.24 | 3.36 ± 0.37 |
| CHL-3000 | + | np | 4.62 ± 0.09 | 7.00 ± 0.00 |
| CHL-3.50. | + | np | 5.05 ± 0.02 | 6.50 ± 0.00 |
| CHM-200. | ++ | np | 4.33 ± 0.02 | 9.00 ± 0.00 |
| CHM-2.50 | + | np | 4.52 ± 0.01 | 6.00 ± 0.00 |
| CHM-30.0 | + | np | 4.85 ± 0.01 | 6.00 ± 0.00 |
[i] (+): turbid, (++): transparent, (+++): glassy, (−): the gel was not formed, np: not provided, AA 1%: acetic acid water solution 1% (1%)
Figure 1.
Appearance of formulation C940-0.1 (a) solution, (b) gel, PCP-0.225 (c) solution, (d) gel, CHM-2.5 (e) solution.
Table 4.
Injectability of polymeric solutions.
| Formulation | Injection needle diameter | |||
|---|---|---|---|---|
| 0.5 | 0.6 | 0.7 | 0.8 | |
| C940-0.10 | + | + | + | + |
| C940-0.70 | − | − | − | − |
| C940-1.30 | − | − | − | − |
| PCP-0.200 | + | + | + | + |
| PCP-0.225 | + | + | + | + |
| PCP-0.250 | + | + | + | + |
| PCP-0.300 | + | + | + | + |
| PCP-0.400 | + | + | + | + |
| PCP-0.600 | + | + | + | + |
| PCP-1.000 | + | + | + | + |
| CHL-3000 | − | − | − | − |
| CHL-3.50. | − | − | − | − |
| CHM-200. | − | − | − | − |
| CHM-2.50 | − | − | − | − |
| CHM-30.0 | − | − | − | − |
[i] (+): injectable, (−): not injectable
Table 5.
Calculated adjusted coefficient of determination (R2adj) of different mathematical models, fitted to released data in whole dissolution time (0–60 min).
| Formulation | R2adj of mathematical models | ||
|---|---|---|---|
| Zero order | First order | Korsmeyer–Peppas | |
| C940-0.10 | 0.741 ± 0.046 | 0.975 ± 0.003 | 0.999 ± 0.001 |
| PCP-0.225 | 0.637 ± 0.077 | 0.993 ± 0.002 | 0.990 ± 0.003 |
| CHM-2.50 | 0.792 ± 0.032 | 0.956 ± 0.008 | 0.969 ± 0.004 |
Figure 2.
Dissolution profiles and Korsmeyer-Peppas fitting lines of formulations C940-0.1 (○, – • –), PCP-0.225 (▲, ‒‒‒) and CHM-2.5 (□, - - -).
Table 6.
Dissolution parameters of the Korsmeyer–Peppas model and released amount of the drug after 60 min dissolution.
| Formulation | kKP | n | Tlag | T50 | Q60 |
|---|---|---|---|---|---|
| C940-0.10 | 22.98 ± 4.95 | 0.31 ± 0.03 | 2.72 ± 0.21 | 16.54 ± 05.37 | 77.04 ± 5.94 |
| PCP-0.225 | 19.70 ± 2.86 | 0.24 ± 0.04 | 4.04 ± 0.27 | 61.01 ± 20.48 | 48.85 ± 5.74 |
| CHM-2.50 | 16.52 ± 3.42 | 0.39 ± 0.04 | 1.45 ± 0.61 | 19.29 ± 04.88 | 77.35 ± 4.98 |
[i] kKP is the Korsmeyer–Peppas release constant, n is the diffusional exponent, Tlag is the lag time before drug release, T50 is the time (min) when 50% of the drug is released, Q60 is the quantity (%) of drug released after 60 min of dissolution