Bioavailability and in-vivo transdermal delivery of haloperidol

ABSTRACT

Sustained blood level with effective therapeutic blood level in psychotic patients in the range of usual therapeutic dose is favorable. To investigate where this sustained and effective therapeutic blood level and improve in bioavailability could be achieved by using haloperidol/transdermal gel formulation. In-vivo transdermal delivery of haloperidol was studied in rabbits comparing transdermal gel formulation containing 1, 8-cineole as penetration enhancer and oral tablet. Concentrations of haloperidol in plasma were measured by reverse phase HPLC. The pharmacokinetic parameters generated from this study were evaluated statistically using one-way analysis of variance [ANOVA]. The results showed that transdermal gel formulation increased rate and extent of absorption and improve bioavailability of haloperidol. The plasma concentrations of haloperidol were declined in biexponential fashion where the area under the curves and absorption rate C[max]/AUC elimination rate constant K[el], T[max], mean residence time [MRT], mean absorption time [MAT], and total clearance [CL[total]] were significantly different p < 0.05, but volume of distribution [V[d]] did not differ significantly p >0.05.The absolute bioavailability from the oral tablet, and the transdermal formulation was 38% and 57% respectively and highly significant P < 0.01. This study suggest that it is possible to achieve significant sustained therapeutic blood levels for longer time and also suggest that further human investigations of the transdermal dosage are warranted