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EVALUATION

All the above formulated ocular films were evaluated for their average weight and weight

variation, thickness, moisture content, drug content and invitro drug release.

determination of average weight and weight variation

as weight variation between the formulated films can lead to difference in drug content and

invitro behaviour, a study was carried out by weighing 5 films in an electronic balance. The

average weight of a film and its standard deviations were calculated by using the following

formulas.

Average weight of each film = total weight of 5 films

5

Standard deviation () =

x = weight of individual film (g)

X = average weight (g)

n = no. of samples

Determination of film thickness

Thickness of the film is an important factor while considering its drug release from ocular

delivery systems. If the thickness varies from one film to another, the drug release from the

film also vary. So it is a must to keep the thickness of the constant to get reproducible results.

In the present study, the thickness of the formulated films were determined by using a dial

calliper (mitutoyo, japan). The thickness was measured at five different places and the mean

value was calculated.

Determination of drug content

A formulated film having 0.65cm2

surface area was dissolved in methanol in a 100ml

volumetric flask. The contents were shaken for 24hrs. The volume was made up 100ml and

thoroughly mixed, 1ml was withdrawn and diluted to 10ml by using pH 7.4 phosphate buffer,

filtered and analysed spectrophotometrically at 276nm. Same procedure was followed forblank ocular insert containing no drug with same additives.

Drug content =

100

A = expression factor

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Dertermination of moisture content

Moisture uptake can influence the mechanical strength and the drug release of the ocular

insert therapeutic systems. Therefore in the present study determination of the moisture

uptake was done at 79.5% RH, which was attained by keeping a saturated of the ammonium

chloride in a closed dessicator. Initially the films were weighed and then kept at 79.5%RH forfive days and reweighed. The percentage moisture content of the film was calculated by the

following formula.

% moisture content =

100

Invitro drug release study

In order to determine the drug release from the formulated ocular films, a study was

conducted using a franz diffusion cell.

Franz diffusion cell

The franz diffusion cell consist of two compartments, the donor and the receptor

compartment. The donor compartment was in contact with ambient condition of atmosphere.

The receptor compartment, has an effective volume of 10ml and an effective surface area for

permeation 0.65cm2. The receptor cell consists of an outer jacket with an outlet and inlet

arrangement to permit the flow of water maintained at 37 1. The solution in receptor

compartment is stirred by a rod shaped magnetic bead driven by a synchronous motor.

Samples can be withdrawn through a sampling port connected to the receptor compartment.

Both these compartments were held together by using an elastic rubber band.

Experimental procedure

Commercial semi permeable membrane of transparent and regenerated cellusose type was

tied to one end of open cylinder which acted as donor compartment. An ocusert was placed

inside this compartment. The semi permeable membrane acted as corneal epithelium. The

membrane was in contact of the receptor compartment was stirred continuously using a

magnetic stirrer. The samples of 1ml were withdrawn from the receptor compartment at

intervals of 1,2,3,4,5,6,8,10,16,20, and 24hrs and automatically replaced by equal volume of

pH 7.4 phosphate buffer. The samples were analysed spectrophotometrically at 276nm for

drug content. The above procedure was used for all the remaining formulations.