Pravastatin transdermal patch: Effect of the formulation and length of microneedles on in- vitro percutaneous absorption studies

Transdermal patches loaded with pravastatin was previously characterized in another published study by Serrano-Castañeda et al; 2015. These transdermal patches (TP) were generated by the plate casting technique, the in vitro percutaneous absorption studies of TP were evaluated for three different formulations of TP with different quantities of Pluronic F-127 (PF-127): i) without PF-127 (TP W), ii) 1% of PF-127 (TP 1%), and iii) 3% of PF-127 (TP 3%) and using solid microneedles as a penetration enhancer with two different lengths: i) 0.25mm and ii) 2.25mm and iii) in vitro permeation studies without using microneedles on TP. The fluxes (F), time lag (tLag) and permeability constants (kp) for each formulation were: TP W (F:38.5µg/cm2*h, tLag:18.97h and kp:5.9x10-3cm/h), TP W with microneedles of 0.25 mm (F:103.3 µg/cm2*h, tLag: 20.76 h and kp: 0.0158 cm/h), TP W and microneedles of 2.25 mm (F:105.2µg/cm2*h, tLag: 21.16 h and kp: 0.0159cm/h), TP 1% (F:90 µg/cm2*h, tLag: 19.48 h and kp: 0.0137 cm/h), TP 1% with microneedles of 0.25 mm (F:111.4µg/cm2*h, tLag:19.11h and kp:0.017cm/h), and TP 1% with microneedles of 2.25 mm (F:115.2µg/cm2*h, tLag:16.73h and kp:0.017cm/h), TP 3% (F:40.9µg/cm2*h, tLag:20.45h and kp:0.0062 cm/h), TP 3% with microneedles of 0.25 mm (F:67.1 µg/cm2*h, tLag: 21.79h and kp:0.0102cm/h) and TP 3% with microneedles of 2.25 (F:70.5 µg/cm2*h, tLag:20.44h and kp:0.0107cm/h). Results show that the formulation of TP affects the pravastatina flux and kp parameters, however the length of microneedles only has important effect on time lag (tLag).