AbstractsBiology & Animal Science

Indomethacin (IND) is a potent non-steroidal anti-inflammatory drug used in the treatment of rheumatoid arthritis, osteoarthritis, acute gout and other disorders. IND is available worldwide mostly in the form of capsules and suppositories, however, these formulations usually create side effects. Consequently, an alternate route of administration to avoid or minimize side effects may be found in the form of semisolid dermatological formulations, now available in few countries. The specific goals of this study were: (I) to determine the solubility of IND using different co-solvents: hexylene glycol (HG), propylene glycol (PG), polyethylene glycol 300 (PEG), butylene glycols (1,2 BG; 1,3 BG and 1,4 BG) and ethanol (ETOH). 1% (w/w) Tween® 80 or polyvinyl pyrrolidone (PVP-25) were used as enhancers; (II) to develop suitable topical gel preparations using 20% (w/w) Pluronic® (PF-127) or 1% (w/w) Carbopol ETD® 2001 (C2001) as gelling agents and HG or PEG 300 as solvents (1% (w/w) Tween® 80 and PVP-25 were added as excipients); (III) To evaluate the effect of composition of prepared gel formulations on the following parameters: appearance, crystallization, pH and rheological behaviour and (IV) to investigate the influence of storage time and storage conditions on the characteristics of the gels. These results indicate that all the solvents tested increased the solubility of IND to varying degrees. Tween® 80 and PVP-25 only slightly enhanced the solubility of IND. 1% (w/w) IND was able to form a structural gel with both PF-127 and C2001. Storing the INDPF-127 gels at 6°C resulted in the precipitation of IND. All gels stored at room temperature exhibited good stability. The gels stored at 45°C developed a dark yellow colour. Gels with C2001 and PF-127/PEG had slightly decreased viscosities with increasing storage time, while the gels with PF-127/HG showed increase in viscosities with time. In conclusion, the water solubility of IND was increased by the addition of co-solvents. 1% (w/w) IND gel can be suitable for using as a gel formulation and it is stable at room temperature. The search for suitable gels for IND topical formulation needs to be continued with more stability studies. Moreover, in-vitro and in-vivo experiments will be necessary for providing data on bioavailability.