Prolonged And Floating Drug Delivery System Of Gabapentin For Effective Management Of Pain In Spinal Cord Injury

Gabapentin is an effective drug in post-traumatic spinal injury induced neuropathic pain. But it requires high dosage and frequency in the management of neuropathic pain. As it is typically absorbed from the upper intestine its floating microspheres were prepared in order to improve the drug release with prolonged drug delivery. The floating microspheres of gabapentin were prepared using two polymers polyvinyl alcohol and carbopol 934 and characterized for drug loading, particle size, floating time, in vitro drug release, in vivo analgesic activity and clinical analgesic study. The physicochemical characterization of floating microspheres showed high percentage drug loading ranging from 81.20 +/- 0.04-91.08 +/- 0.86%. The particle size was found to be 415.50 +/- 18.12-524.68 +/- 10.09 mu m in optical microscopy. The floating time in vitro was 5.88 +/- 0.25-9.02 +/- 0.12 h. The microspheres showed prolonged drug release extending to more than 12 h in the in vitro study. The percentage drug release was found to be 79.24, 84.28, 92.24 and 90.12% at the end of 12 h. The formulation MG4 showed best in vivo analgesic activity in rats (by hot plate method). In human MG4 showed better mean pain score at Visual Analogue Scale (VAS) at each time point of observation in 4 week study. The MG4 showed mean pain score of 4.96 +/- 0.45 as compared to that of conventional tablet treatment (5.99 +/- 1.01). The significant improvement in neuropathic pain by the prepared floating microspheres was obtained. It was concluded that the floating microspheres of gabapentin may serve as a potential alternative of conventional dosage forms which require high dosage frequency and still result in effective pain management.