Assessing the permeability of a potent antipsychotic drug (Risperidone) through human cadaver skin: Effect of permeability enhancers and formulation variables

The novel approaches of drug delivery are continuously being introduced, which help for minimizing the drug doses and maximizing the biological availability of drug. Transdermal delivery of drug is a very interesting phenomenon as the drug avoids first pass metabolism, therefore the direct entry of drug into the systemic circulation will take place with increased biological availability. The system that release drug at zero order rate, for it frequency of dosing is not much important than the capacity of the system i.e. the quantity of drug for transdermal system. There are very less chances of over or under dosing with transdermal delivery as the result of prolonged preprogrammed delivery of drug at the required therapeutic rate. Such delivery is easily accessible for self medication, and hence it is well acceptable by the patients. Administration and even termination of drug both can be possible whenever desired.;In this study, a transdermal formulation of a potent antipsychotic drug Risperidone was developed and optimized using different gelling agents and permeability enhancers. Risperidone is mainly used to treat schizophrenia (including adolescent schizophrenia), schizoaffective disorder, the mixed and manic states associated with bipolar disorder, and irritability in people with autism. It is available in forms of tablets, orally disintegrating tablets and oral solution. An HPLC method for the drug Risperidone was developed and validated, which was used to carry out the assay of a formulation. In-vitro permeability studies were carried out using modified Franz cells with cellulose membrane as a barrier to optimize the gelling agents and their concentrations. Furthermore, to assess the in-vivo drug release/permeation of the drug the formulation exhibiting optimum drug release was evaluated using human cadaver skin as a barrier. Here, permeability enhancers were incorporated in formulations to analyze the effect of enhancers on the permeability of the drug.;Mass balance and accelerated stability studies of the formulations were carried out including stability assays; viscosity and pH of the formulations were studied.;From the studies it was found that drug permeation depends on the type and concentration of the gelling agents. Incorporation of permeability enhancers creates the physiological changes to the human cadaver skin and it changes the drug permeation. Accelerated stability studies data helped to determine the long term stability of a product. It is concluded that effect of temperature and relative humidity modifies the viscosity and pH of the formulation as well as the change in drug concentration was also altered.