Samples equivalent to 15 mg of meloxicam were added to 900 mL of dissolution medium in a 1000-mL cylindrical beaker. The paddle
speed was 100 rpm. At intervals of 5, 10, and 15 min, 10-mL samples were withdrawn during a period of 90 min. The same volume
of preheated dissolution medium was infused into the medium after each sample was taken, to maintain a constant volume of
the dissolution medium throughout the test. The samples were filtered using filter paper (41, Whatmann International, Maidstone,
UK), and the meloxicam content was determined spectrophotometrically at λmax 363.5 nm using a Shimadzu UV-1700 spectrophotometer (Shimadzu). Data were analyzed with PCP-Disso software (Poona College
of Pharmacy, Pune, India).
Permeation study.
Female hairless mice (8–10 weeks old) were killed by cervical dislocation, and their full-thickness skins removed. The adhering
fat and visceral tissue were removed. To remove extraneous debris and leachable enzymes, the dermal side of the skin was put
in contact with a saline solution for 2 h. The dermal side was then treated with 1-mL phosphate buffer for 6 h to equilibrate
the membrane before starting the diffusion experiment. The skin was stretched over the end of an open-ended glass tube. The
tube was immersed in a 400-mL beaker containing 100-mL phosphate buffer (pH 7.4) and kept in a vertical position so that the
membrane was below the surface of the buffer solution. The surface area available in diffusion was 2.5 cm2. The tube (donor) and beaker (receptor) were maintained at 37 °C and shaken in a thermostatically controlled shaker. A 3-mL
aliquot of saturated buffer solutions (pH 7.4) of meloxicam as a pure drug and melt granules prepared with myrj-52 were inserted
one by one into the tube. For 6 h, 5-mL samples were removed from the receptor at intervals and analyzed spectrophotometrically
at 363.5 nm. The experiment was repeated three times, and the average of the readings was calculated.
Stability studies.
For stability studies, about 200 mg each of pure drug, melt granulation, solid dispersion, and physical mixture were weighed
into glass vials. The samples were monitored for three months at 30 °C and 60% relative humidity (RH). Samples were removed
periodically and characterized by dissolution-rate measurement and the presence of crystallinity.
Preparation and characterization of tablets.
Melt granules equivalent to 15 mg of meloxicam with 5% Ac-Di-Sol (FMC BioPolymer, Philadelphia, PA) were geometrically mixed
and lubricated with 1% w/w magnesium stearate, which was manufactured according to Indian Pharmacopoeia standards. Formulations
were passed through a #30 mesh sieve and directly compressed with a 12-station tablet machine (Minipress II MT, Karnawati
Rimek, Ahmedabad, India) with an 8-mm punch diameter and circular punches with flat faces. The machine setting was adjusted
to produce 160-mg tablets with a hardness of 3.5 6 0.25 kg/cm2 .
Table I: Studies of various tablet parameters.
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The tablets' friability (n = 10) was determined with a friabilator (Roche, Veego Scientific, Mumbai, India). A hardness tester (Monsanto, LabHosp, Mumbai,
India) determined the hardness of tablet samples (n = 10). The disintegration of tablets (n = 6) was determined using a disintegration-test apparatus (Veego Scientific) in distilled water at 37 ± 0.5 °C (see Table
I).
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