Preparation and evaluation of mucoadhesive beads/discs of alginate and algino-pectinate of piroxicam for colon-specific drug delivery via oral route.

BACKGROUND: Targeted drug delivery to colon would ensure direct treatment at the disease site, decrease in dose administration and reduction side effects improved drug utilization.

OBJECTIVE: The purpose of this research was to decrease gastric side effects of piroxicam by formulating microspheres of alginate and algino-pectinate beads of the drug.

MATERIALS AND METHODS: Ionotropic gelation was used to entrap piroxicam into alginate and algino-pectinate mucoadhesive microspheres as a potential drug carrier for oral delivery of piroxicam. Microparticles with different drug to polymers ratio were prepared and characterized by encapsulation efficiency, particle size, DSC (differential scanning calorimetric), mucoadhesive property, gastroretentive time and drug release studies.

RESULTS: The best drug to polymer ratio of microparticles was 1:2.5 (F1) with Na-Alg and 1:7.5 (F4) with Alg-Na with pectin, respectively. The microparticles F1 and F4 showed 28.80%, 50.01% loading efficiency, 82.57%, 82.31% production yield and 945.4, 899.91 µm mean particle size. DSC showed stable character of piroxicam in drug-loaded microparticles and revealed amorphous form. It was found that microparticles (Na-Alg) prepared had faster release and microparticles (Alg-Na and pectin mixture) prepared had slower release than untreated piroxicam (P < 0.05). Microparticles (mixture of Na-Alg and pectin) exhibited very good percentage of mucoadhesion and flowability properties. Mucoadhesion strength and retention time study showed better retention of piroxicam microparticles in intestine. Besides, there was a significant higher retention of mucoadhesive microparticles in upper GI tract.

CONCLUSIONS: Algino-pectinate mucoadhesive formulations exhibited promising properties of a sustained release form for piroxicam and provided distinct tissue protection in stomach.