Methods for reduction of cohesive forces between carrier and drug in DPI formulation

Abstract

Dry powder inhaler (DPI) has become a well accepted drug delivery for pulmonary system to treat many related diseases including symptomatic and life threatening diseases. Successful delivery of dry powder to the lung requires careful consideration of powder production process, formulation and inhaler device. The formulation of DPI mostly comprises of lactose as a carrier for drug delivery. In DPI formulation, particulate interactions within the formulation govern both the drug dissociation from carrier particles and the disaggregation of drug into primary particles with a capacity to penetrate deep into lung. Two contradictory requirements must be fulfilled for this type of dry powder formulation. On one hand, adhesion between carrier and drug must be sufficient for the blend drug/carrier to be stable. On the other hand, adhesion drug/carrier has to be weak enough to enable the release of drug from carrier during patient inhalation. Thus the carrier use restricted due to detachment problem. Different methods are proposed to reduce the cohesive forces between drug and carrier to desired level. Various studies conducted for understanding the mechanism of deposition into lungs and making formulation with optimum carrier drug cohesive force. This review provides information on various processes involved in reducing the cohesive forces between drug and carrier, to a required level.