Gastric-resistant isoniazid pellets reduced degradation of rifampicin in acidic medium

Fátima Duarte Freire, Manuela Bernardo Câmara, Monique Gomes Dantas, Cícero Flávio Soares Aragão, Túlio Flávio Accioly de Lima e Moura, Fernanda Nervo Raffin
2014 Brazilian Journal of Pharmaceutical Sciences  
Isoniazid and rifampicin are considered the first-line medication for preventing and treating tuberculosis. Rifampicin is degraded in the stomach acidic environment, especially when combined with isoniazid, factor contributing to treatment failure. In this study, gastric-resistant isoniazid pellets were obtained to physical contact of this drug with rifampicin and to bypass the stomach´s acidic environment. The pellets were fabricated using the extrusion-spheronization technique. The coating
more » ... que. The coating process was conducted in a fluid spray coater using Acrycoat L 100(r) solution as the coating agent. The pellets obtained were submitted to a dissolution test in HCl 0.1 N and phosphate buffer media. The results indicated that optimum gastric-resistance was only attained with the highest amount of coating material, with isoniazid almost fully released in phosphate buffer. The amount of rifampicin released from its mixture with non-coated isoniazid pellets in HCl 0.1 N was less than that released from its mixture with the enteric-coated pellets. Acrycoat L 100(r) was shown to be an effective enteric/gastric-resistant coating since the stability of rifampicin appeared to be enhanced when physical contact of this drug with isoniazid was prevented at low pH.
doi:10.1590/s1984-82502014000400010 fatcat:psokdcovrbexhivyi3u7esxlby