Gabapentin in Elastic Liposomes: Preparation, Characterization, Drug Release, and Penetration Through Porcine Skin

In the outpatient pharmacy compounding, gabapentin, an anti-epileptic agent, has been commonly prescribed to be prepared alone or in combination with other agents in Pluronic lecithin organogel for transdermal pain management and palliative care. The objective of this study was to formulate and characterize gabapentin encapsulated elastic liposomes and then compare the gabapentin-based liposomes with compounded gabapentin-based Pluronic lecithin organogel regarding their efficiency in transdermal delivery of gabapentin. We demonstrated that our small 100-nm unilamellar vesicles of gabapentin encapsulated approximately 6.9 mg/mL Å} 0.2 mg/mL with up to 70% of encapsulation efficiency. Gabapentin released slowly from liposomes over 12 hours while it rapidly released from Pluronic lecithin organogel within 4 hours. We also showed that after 24 hours liposomes significantly accelerated the percutaneous penetration of gabapentin through the porcine skin leading to higher cumulative drug concentrations (~98% of drug permeated with a mean flux of 188.94 µg/cm2/h Å} 42.16 µg/cm2/h) as compared to Pluronic lecithin organogel (~55 % of drug permeated with a mean flux of 56.32 µg/cm2/h Å} 41.93 µg/cm2/h). In conclusion, the elastic liposomal formulation showed higher efficiency than the compounded Pluronic lecithin organogel in the transdermal delivery of gabapentin through porcine skin.