subject: Studies on Formulation and evaluation of Piraoxicam-Solid Dispersion [print this page] Studies on Formulation and evaluation of Piraoxicam-Solid Dispersion
Preparation of Piroxicam Solid dispersions :
Solvent Method: PVP and Piroxicam were dissolved inan adequate amount of chloroform to get a clear solution. Then the solvent was removed by evaporation at 40 deg C while continuous stirring. The mass obtained was crushed, pulverized and sifted through number 60 mesh. The different ratios of drug to polymer were used ( 1:1, 1:2, 1:3, 1:4 &1: 5)
Fusion method: Mannitol as melted in a china dish, then the Piroxicam was added to the melted Mannitol and mixed thoroughly. It was then cooled immediately in an ice batch. The mass obtained was crushed, pulverized and sifted through number 60 mesh. The different ratios of drug to polymer were used (1:2, 1:3, 1:4, 1: 5 and 1: 6). In this case 1: 1 ratio was not prepared due to the amount was tool less to handle in laboratory.
Compatibility studies : The compatibility studies were conducted to confirm that the drug does not react with the components in experimental conditions. Whish was confirmed by TLC, IR and X ray diffraction analysis.
A) Thin layer Chromatography : UV light at 254nm used as visualizing agent. Rf value found for the both formulation 0.93, and for standard Rf value: 0.93 indicating that the samples were unchanged as that of Pure Piroxicam. There were no additional spot were appeared on plate indicating that there was no change in chemical structure.
B) IR Spectral studies: The IR spectra were recorded on Shimadzu FTIR-8300 model. The IR spectra of Pure Piroxicam, Piroxicam-PVP and Piroxicam-Mannitol solid dispersion are compared and found that in formulations shifting of peaks to higher wave number ( peaks of Amide carbonyl, Oh- stretching) were observed, which was due to change in crystalline form of drug to amorphous form, the same was confirmed by x ray diffraction study.
C) X ray diffraction studies: X ray diffraction studies were done for pure drug and formulation. The result observed For Piroxicam Mannitol formulation reduced peak intensity due to reduced crystalline size and for the Piroxicam PVP formulation sharp diffraction peaks for Piroxicam disappeared due to the complete conversion of crystalline form to amorphous form.
Inviro release studies : Piroxicam- PVP and Piroxicam- Mannitol formulations were subjected to invitro release studies by using 0.1 M hydrochloric acid using USP dissolution apparatus. Studies were conducted in dublicate to confirm the consistency in release. Results were plotted by using
Zero order kinetics
First order kinetics
Higuchi's Model
Hixon and Crowell's cube root dissolution rate equation
Dissolution efficiency
In case of PVP Piroxicam formulation as the carrier proportion increased, dissolution rate also increased. But in case of Piroxicam Mannitol formulation, did not exhibit the similar trend although the formulations with this carrier gave higher dissolution rates than pure Piroxicam. This deviation in the trend may be attributed to the tendency of Mannitol to form a sticky mass in higher proportions resulting in pellicle formation.
Conclusion : Solid Dispersion technology with PVP as carrier polymer for Piroxicam dosage form lie tablets/ capsules may prove to be a highly potential means of improving the drug's dissolution and inturn its bioavailability. Such draw backs associated with the basic drug molecule therefore can be overcome.
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