Preparation of a polymeric reservoir naltrexone delivery device: Effect of PEG content of the PLA membrane on drug release

Rassoul Dinarvand, Shadi H Moghadam, Pantea Sayar, Mahsa Alaee and Fatemeh Atyabi

Background: Naltrexone is an orally active opioid agonist that has the potential for use as a t reat ment option for opiat e addict ion. However, in order for the drug to be effective, sufficient blood levels must be maint ained for 4 to 8 months, which t ypically requires self - administ rat ion by the pat ient , resulting in complications.
Aim: The aim of this st udy was to develop a polymeric reservoir device cont aining nalt rexone.
Materials & methods: The reservoir device was prepared using high-molecular-weight poly-L-lactide and the cylindrical device by dipping a stainless-steel rod in a met hylene chloride solut ion of polylactic acid (PLA). High-molecular-w eight PLA w as used to t ake advant age of the low biodegradation rate of the polymer, in order to obtain const ant drug release from the device based on the diffusion mechanism rather than biodegradation of the polymer. The impact of the polymeric device weight and polyethyleneglycol content of the polymeric membrane of the device on the release of nalt rexone f rom the device w as st udied.
Results: Rate of drug release f rom the reservoir device was shown to be successf ully regulat ed by controlling the device w eight as well as the amount of hydrophilic addit ive in the polymeric membrane of the device. The higher the amount of the hydrophilic content of the polymeric membrane, the fast er the rate of drug release from the device.
Conclusion: Prepared reservoir devices released their drug content through the use of a high-molecular-w eight PLA. The presence of NaCl as an osmot ic agent did not af fect the release profile of nalt rexone – an indicator that diffusion is the mechanism of release of nalt rexone f rom the PLA reservoir syst em.