The main purpose of the present study was to develop ocuserts of Fluconazole
Eye drops and eye ointments are conventional ocular dosage forms. They have certain disadvantages like frequent administration, poor availability, massive and unpredictable doses, and drainage of medication by tear/nasolacrimal fluid [
Fluconazole was gift samples from Waksman and Selman Pharmaceuticals, Anantapur, India.
The preparation of ocuserts involved three different steps [
The polymeric drug reservoir films were prepared by dissolving 1.0, 1.5, and 2.0% of HPMC-K4M in 15 mL of double distilled water. Along with this 26.95 mg of binary mixture containing Fluconazole
After complete mixing the solution was cast in Petri dish (previously lubricated with Glycerin) using a ring of 5.0 cm diameter and with a funnel inverted on the surface (for uniform evaporation of solvent). The cast solution was allowed to evaporate by placing it inside a hot air oven maintained at 37 ± 2°C, 30 ± 0.5% of RH for 24 hours. After drying the medicated films of 8 mm diameter each containing 300 mg of drug were cut using a stainless steel borer, which is previously sterilized.
A weighed quantity of ethyl cellulose was dissolved in 10 mL of acetone to obtain 4, 5, and 6% polymeric solutions. Stirring was continuously maintained until the clear solution was obtained. These solutions were poured in Petri dish (previously lubricated with Glycerin) using a ring of 5.0 cm diameter. The solution was evaporated slowly by inverting a glass funnel on a petri dish at room temperature for 12 hours. The dried films were cut into 9 mm diameter using a stainless steel borer.
A medicated reservoir disc was sandwiched between two rate controlling membranes. Then this whole unit was placed for 4-5 min over a wire mesh inside the desiccator. Desiccator was previously saturated with ethanol/acetone (60 : 40). This procedure resulted into successful sealing of the medicated reservoir film between two rate controlling membranes. The sealed ocuserts were stored in an airtight container under ambient conditions.
Plasticizer weight was based on the weight of the polymer. All the above experimentation was carried out under laminar airflow to maintain the sterility conditions of ophthalmic products. The composition of ocusert formulations was represented in Table
Composition of various polymers in different formulations per ring.
Formulation | HPMC-K4M (%w/v) | EC (%w/v) | Dibutyl phthalate (%v/w) | Fluconazole |
---|---|---|---|---|
F-1 | 1.0 | 4.0 | 10.0 | 300 |
F-2 | 1.0 | 5.0 | 10.0 | 300 |
F-3 | 1.0 | 6.0 | 10.0 | 300 |
F-4 | 1.5 | 4.0 | 10.0 | 300 |
F-5 | 1.5 | 5.0 | 10.0 | 300 |
F-6 | 1.5 | 6.0 | 10.0 | 300 |
F-7 | 2.0 | 4.0 | 10.0 | 300 |
F-8 | 2.0 | 5.0 | 10.0 | 300 |
F-9 | 2.0 | 6.0 | 10.0 | 300 |
12 mL of the cast solution was poured into petri dish to prepare circular cast film.
Various formulations of ocuserts.
The compatibility of drug with the excipient used was studied by Fourier transform infrared (FTIR) spectroscopy. The FTIR spectrums of Fluconazole and Formulation (F-5) blend were studied by using FTIR spectrophotometer (Perkin Elmer, spectrum-100, Japan) using the KBr disk method (5.2510 mg sample in 300.2502 mg KBr). The scanning range was 500 to 4000 cm−1, and the resolution was 1 cm−1. This spectral analysis was employed to check the compatibility of drugs with the polymers used.
The ocuserts were evaluated for their physical characters such as shape, colour, texture, and appearance.
Films were evaluated for the thickness using a vernier caliper (For-bro Engineers, Mumbai, India). The average of 5 readings was taken at different points of film, and the mean thickness was calculated. The standard deviations (SDs) in thickness were computed from the mean value [
For drug content uniformity, the ocuserts were placed in 5 mL of pH 7.4 phosphate buffer saline and were shaken in orbital shaker incubator at 50 rpm to extract the drug from ocuserts. After incubation for 24 h, the solution was filtered through a 0.45
The weight variation test was carried out using electronic balance (Sartorius GmbH, Gottingen, Germany), by weighing three patches from each formulation. The mean value was calculated, and the standard deviations of weight variation were computed from the mean value.
A small strip of ocusert was cut evenly and separately folded at the same place till it breaks. The number of times the ocusert could be folded at the same place without breaking gave the folding endurance [
The percentage moisture absorption test was carried out to check physical stability or integrity of ocular films. Ocular films were weighed and placed in a dessicator containing 100 mL of saturated solution of aluminium chloride, and 79.5% humidity was maintained. After three days the ocular films were taken out and reweighed. The percentage moisture absorption was calculated using the following equation [
The percentage moisture loss was carried out to check integrity of the film at dry condition. Ocular films were weighed and kept in a dessicator containing anhydrous calcium chloride. After 3 days, the ocuserts were taken out and reweighed; the percentage moisture loss was calculated using the following equation [
The ocuserts were coated on the lower side with ethyl cellulose (to avoid sticking to the dish) then weighed (
The ocuserts from each batch were taken and placed in 15 mL vials containing 10 mL of pH 7.4 phosphate buffered saline. The vials were placed in an oscillating water bath at 32 ± 1°C with 25 oscillations per minute. 1 mL of the drug releasing media was withdrawn at various time intervals of 1, 2, 4, 8, 12, 16, and 20 hours and replaced by the same volume of phosphate buffer saline pH 7.4. These samples were filtered through 0.45
Out of 5 batches of formulations F-5 and F-8 were taken for
Albino rabbits of either sex (New-Zealand strain), weighing between 2.5–3.0 kg, were used for the experiment. The animals were housed on individual cages and customized to laboratory conditions for one day (received free access to food and water).
The ocuserts containing Fluconazole were taken for
Ocuserts were removed carefully at 1, 2, 4, 8, 12, 16, and 20 hours and analyzed for drug content as dilution mentioned in drug content uniformity. The drug remaining was subtracted from the initial drug content of ocuserts that will give the amount of drug released in the rabbit eye. Observation for any fall out of the ocuserts was also recorded throughout the experiment. After one week of the washed period the experiment was repeated for two times as before.
The potential ocular irritation and/or damaging effects of the ocusert under test were evaluated by observing them for any redness, inflammation, or increased tear production. Formulation was tested on five rabbits by placing the inserts in the cul-de-sac of the left eye. Both eyes of the rabbits under test were examined for any signs of irritation before treatment and were observed up to 12 hours [
Stability testing has become an integral part of formulation development. It generates information on which, proposed for shelf life of drug or dosage forms and their recommended storage conditions are based.
In the present study, the formulation F-5 was selected for the study, and ocuserts were packed in amber-colored bottles tightly plugged with cotton and capped. They were exposed to various temperatures (60°, 40°, 20°, 10°, and 0°C) for 30 days. At regular intervals, the ocuserts were taken in 5 mL of pH 7.4 phosphate buffer saline and were shaken in orbital shaker incubator at 50 rpm to extract the drug from ocuserts. After incubation for 24 h, the solution was filtered through a 0.45
The compatibility of Fluconazole with the polymer used (
Fluconazole pure drug.
Fluconazole and
Fluconazole with HPMC.
Fluconazole with EC.
Fluconazole ocusert.
The thickness of the formulated ocuserts was uniform and ranged from 0.16 ± 0.001 to 0.17 ± 0.005 mm. The little variation observed with formulation F-5 might be due to the more concentration of rate controlling membrane. The values of uniformity of weight were found to vary from 15.89 ± 0.028 to 18.48 ± 0.153 mg. All formulations (F-1 to F-9) showed good uniformity in weight. After the moisture loss the ocuserts showed no change in integrity, and it ranged from 6.29 ± 0.109 to 9.68 ± 0.045% and the moisture absorption ranged from 4.78 ± 0.222 to 9.84 ± 0.148%. The highest moisture absorption was marked from formulation F-6 (9.84 ± 0.148%); this may be due to the presence of larger concentration of hydrophilic polymer HPMC-K4M. The folding endurance ranged from 74 ± 6.681 to 98 ± 5.621, and no cracks were observed. Formulations F-9, F-3, and F-8 showed maximum folding endurance. The formulated ocuserts were found to have uniformity in drug content: formulation F-4 showed the least drug content (85.65 ± 9.657%) and formulation F-9 showed the highest drug content (97.26 ± 2.255%). The surface pH values of all films were in the range 4.5–6.5. All these values were represented in Table
Physicochemical evaluation of different formulations.
Formulation | Thickness (mm) | Weight uniformity (mg) | Moisture loss (%) | Moisture absorption (%) | Folding endurance | Drug content (%) |
---|---|---|---|---|---|---|
F-1 | 0.16 ± 0.002 | 17.55 ± 0.107 | 7.84 ± 0.015 | 4.78 ± 0.222 | 74 ± 6.681 | 89.51 ± 4.568 |
F-2 | 0.16 ± 0.001 | 16.37 ± 0.109 | 8.54 ± 0.084 | 5.35 ± 0.155 | 85 ± 5.847 | 91.16 ± 6.593 |
F-3 | 0.16 ± 0.004 | 18.35 ± 0.045 | 9.68 ± 0.045 | 6.28 ± 0.169 | 91 ± 6.656 | 90.26 ± 2.658 |
F-4 | 0.16 ± 0.005 | 15.89 ± 0.028 | 6.29 ± 0.109 | 7.84 ± 0.184 | 68 ± 5.517 | 85.65 ± 9.657 |
F-5 | 0.17 ± 0.003 | 16.89 ± 0.116 | 7.57 ± 0.227 | 8.94 ± 0.167 | 74 ± 8.594 | 89.51 ± 7.215 |
F-6 | 0.16 ± 0.004 | 18.48 ± 0.153 | 8.52 ± 0.024 | 9.84 ± 0.148 | 85 ± 6.849 | 95.21 ± 4.123 |
F-7 | 0.16 ± 0.006 | 15.98 ± 0.117 | 7.94 ± 0.087 | 7.51 ± 0.153 | 85 ± 6.598 | 88.32 ± 6.597 |
F-8 | 0.16 ± 0.005 | 16.84 ± 0.157 | 8.54 ± 0.247 | 8.15 ± 0.048 | 91 ± 2.955 | 95.84 ± 5.648 |
F-9 | 0.17 ± 0.005 | 17.97 ± 0.148 | 9.19 ± 0.028 | 9.84 ± 0.058 | 98 ± 5.621 | 97.26 ± 2.255 |
All values were expressed as mean ± S.D; number of trials
Water uptake studies were performed for optimized formulations (F-5 and F-8). The water uptake was gradually increasing with time indicating the good wetting nature of the ocuserts. Water uptake values of the formulated ocuserts were shown in Table
Water uptake and swelling behavior.
Time (hours) | Water uptake (mg) | |
---|---|---|
F-5 | F-8 | |
0 | 4.51 ± 0.037 | 4.59 ± 0.253 |
1 | 6.29 ± 0.017 | 5.54 ± 0.214 |
2 | 8.45 ± 0.158 | 7.68 ± 0.314 |
3 | 9.79 ± 0.012 | 10.15 ± 0.168 |
4 | 11.54 ± 0.268 | 12.35 ± 0.247 |
5 | 13.57 ± 0.232 | 16.18 ± 0.658 |
All values were expressed as mean ± S.D; number of trials
Based on the highest regression value
Kinetic values obtained from zero-order release profile.
Formulation | Slope | Regression coefficient | |
---|---|---|---|
F-1 | 3.5491 | 0.9056 | 4.4564 |
F-2 | 4.2156 | 0.9035 | 5.3535 |
F-3 | 4.6656 | 0.9725 | 5.2641 |
F-4 | 4.2471 | 0.8946 | 5.4849 |
F-5 | 4.7592 | 0.9721 | 5.3749 |
F-6 | 4.5875 | 0.9365 | 5.5367 |
F-7 | 4.5088 | 0.9358 | 5.0569 |
F-8 | 4.3654 | 0.9064 | 5.2698 |
F-9 | 4.4845 | 0.9861 | 4.8976 |
Kinetic values obtained from first order release profile.
Formulation | Slope | Regression coefficient | |
---|---|---|---|
F-1 | 0.0287 | 0.9851 | −0.0721 |
F-2 | 0.0265 | 0.9638 | −0.1231 |
F-3 | −0.0659 | 0.9691 | −0.1251 |
F-4 | −0.0535 | 0.9947 | −0.1168 |
F-5 | −0.0059 | 0.8446 | −0.2059 |
F-6 | −0.0735 | 0.9646 | −0.1464 |
F-7 | −0.0651 | 0.8945 | −0.1443 |
F-8 | −0.0655 | 0.9259 | −0.1498 |
F-9 | −0.0559 | 0.9548 | −0.1053 |
Kinetic values obtained from Higuchi-matrix release profile.
Formulation | Slope | Regression coefficient | |
---|---|---|---|
F-1 | 18.026 | 0.9964 | 15.105 |
F-2 | 21.854 | 0.9934 | 49.534 |
F-3 | 21.489 | 0.9816 | 19.779 |
F-4 | 20.175 | 0.9946 | 19.549 |
F-5 | 21.816 | 0.9847 | 20.765 |
F-6 | 22.168 | 0.9916 | 20.146 |
F-7 | 22.016 | 0.9894 | 20.149 |
F-8 | 21.534 | 0.9916 | 20.146 |
F-9 | 21.146 | 0.9679 | 19.243 |
Kinetic values obtained from Korsmeyer Peppa’s release profile.
Formulation | Slope | Regression coefficient | ||
---|---|---|---|---|
F-1 | 0.4998 | 0.9995 | 16.489 | 0.5652 |
F-2 | 0.5334 | 0.99749 | 18.754 | 0.5329 |
F-3 | 0.7649 | 0.9967 | 10.325 | 0.7126 |
F-4 | 0.5502 | 0.9969 | 17.984 | 0.5984 |
F-5 | 0.7449 | 0.9895 | 10.987 | 0.7687 |
F-6 | 0.6194 | 0.9946 | 16.028 | 0.6295 |
F-7 | 0.7743 | 0.9685 | 14.987 | 0.6985 |
F-8 | 0.5764 | 0.9765 | 17.961 | 0.5987 |
F-9 | 0.7716 | 0.9962 | 8.9986 | 0.7748 |
Kinetic values obtained from Hixson Crowell’s release profile.
Formulation | Slope | Regression coefficient | |
---|---|---|---|
F-1 | 0.0709 | 0.9749 | −0.0215 |
F-2 | −0.1527 | 0.9369 | −0.0248 |
F-3 | −0.1029 | 0.9854 | −0.0268 |
F-4 | −0.1016 | 0.9785 | −0.0351 |
F-5 | −0.1546 | 0.9359 | −0.0246 |
F-6 | −0.1239 | 0.9547 | −0.0346 |
F-7 | −0.1129 | 0.9358 | −0.0392 |
F-8 | −0.1326 | 0.9847 | −0.0246 |
F-9 | −0.1264 | 0.9958 | −0.0385 |
Zero-order plots.
First-order plots.
Higuchi’s plots.
Korsmeyer Peppa’s plots.
Hixson Crowell’s plots.
For
Plots of
Rabbit with ocusert.
Stability data indicates that the formulations were stable, no major degradation was found (Table
Data obtained from stability studies.
Temp. (°C) | Ab. Temp ( | Rec | D.R.C. ( | Log |
---|---|---|---|---|
60 | 333 | 0.00305 | 0.00164 | −2.78516 |
40 | 313 | 0.00319 | 0.00179 | −2.74715 |
20 | 293 | 0.00341 | 0.00059 | −3.22915 |
10 | 283 | 0.00353 | 0.00036 | −3.44369 |
0 | 273 | 0.00366 | 0.00028 | −3.55284 |
25 | 298 | 0.00335 | 0.00019 | −3.72125 |
Temp: Temperature; Ab. Temp = Absolute Temperature; Rec
In the present study an attempt was made to develop ocuserts of Fluconazole with improved bioavailability, avoidance of repeated administration and dose reduction. From the experimental finding, it can be concluded that Hydroxy Propyl methyl cellulose is a good film forming hydrophilic polymer and is a promising agent for ocular delivery. Ethyl cellulose was a satisfactory polymeric ingredient to fabricate the rate controlling membrane of the ocusert system. Incorporation of dibutyl phthalate enhances the permeability of Fluconazole, and thus therapeutic levels of the drug could be achieved. Complexation of Fluconazole with