Pure meloxicam has a low dissolution profile. The percentage of drug dissolved in 50 min is 38.5%. Formation of PM improves
this value. On the other hand, the profiles of MG and SD show a great increase in drug dissolution compared with the profiles
of pure meloxicam. Reults showed that 80.2% and 90.40% of drug dissolved during the first 15 min in MG and SD prepared with
myrj-52, respectively.
The dissolution enhancement can be attributed to the solubilization effect of myrj-52 and improved wettability and dispersibility
of the drug from MG as well as SD (14).
Figure 9: Dissolution profile of melt granules (MG) prepared with myrj-52 after storage at 30 °C and 60% relative humidity
for 3 months.
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The sample mixture of the components also improves the release of meloxicam, thus suggesting that melt granulation using myrj-52
could be a useful method to improve the dissolution rate of meloxicam.
Figure 10: Permeation profile of meloxicam through hairless mouse skin from saturated solution of pure meloxicam and melt
granules (MG) in myrj-52.
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Stability studies.
To evaluate the stability of the granules, in vitro dissolution tests and X-ray analysis were performed on the samples after three months at 30 °C and 60% RH (see Figure 9).
The dissolution profiles of the melt granules stored for three months were similar to those of freshly prepared ones. In addition,
the authors found no difference in the X-ray graph. These results suggest the physical stability of the samples, at least
for the examined time.
Table IV: Permeation rate and permeation coefficient of meloxicam through hairless mouse skin.
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Permeation study.
Figure 10 shows the total amount of drug permeated (μg/cm2 ) through the hairless mice skin during 360 min. The permeation profiles for individual data were linear, and R ranged from 0.970 to 0.999. The results indicated that the hairless mouse skin was permeable to meloxicam and that the percutaneous
absorption might be described by zero-order kinetics during the time of the study. The permeation rate of the drug from its
saturated solution, in phosphate buffer (pH 7.4), across the membrane was calculated from the slope of the graph as μg.cm–2 h–1 (see Table IV).
The higher permeation rate could be attributed to the increased solubility of meloxicam. Thus, the increased drug availability
at the surface of the mice skin formed a concentration gradient.
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