Both the research papers detailed here attempt to formulate alternatives to parenteral delivery, which is inconvenient when repeat administration is required.
Pulmonary delivery shows promise
A poster detailing the investigation into pulmonary delivery of low molecular weight heparin (LMWH) was displayed by researchers at Texas Tech University, US and Barr Pharmaceuticals.
The researchers believe that formulating LMWH into a dry powder inhaler (DPI) would confer significant advantages over current methods. These include enhanced drug stability, greater accuracy in dosing and an overall improvement in patient compliance.
However, to establish DPI as a viable method of administration the researchers needed to study the interaction between LMWH and the lactose carrier. In addition the pulmonary absorption was compared to an aerosolised aqueous solution of the drug.
The results suggest that lactose is a suitable carrier for pulmonary delivery of LMWH, with no strong interaction witnessed between the two elements. There was also an increase in bioavailability over aerosolised aqueous solution when a particle size of 33μm was used.
Rats were used to research this and further work is needed but it does suggest that pulmonary administration may be a route worth exploring.
Details of the research can be found here.
Breaching the transdermal barrier
A different route of administration was investigated by researchers from the College of Pharmacy and Health Sciences, Georgia and California Northstate College of Pharmacy.
Their work, published earlier this year in the International Journal of Pharmaceutics, investigates ways to get LMWH across the stratum corneum (SC).
LMWH is a hydrophilic molecule and consequently does not naturally cross the SC barrier. The researchers found that enhancement strategies had limited value owing to interaction with the SC and epidermal components.
Consequently the researchers investigated the viability of using microneedles and had more success.
This proved particularly effective when used in conjunction with iontophoresis, which suggests that further development may lead to the creation of an effective, minimally invasive administration route.