A novel approach for discriminating lipophilic bisphosphonate-based pharmaceuticals using a potentiometric array.

Bisphosphonates are pharmaceutical compounds commonly used in the treatment of osteoporosis, Paget's disease, and multiple myeloma. Their lipophilicity was evaluated using a sensor array composed of poly(vinyl chloride) (PVC)-based ion-selective membranes (ISMs), modified with a polyaniline (PANI) layer that affects surface properties and acts as an anion-exchanger. The lipophilicity of bisphosphonates including ibandronate, clodronate, risedronate, and alendronate was analyzed in both standard and commercial samples. The influence of membrane composition (presence or absence of an anion-exchanger) and PANI deposition conditions (monomer form and/or salt content) on membrane surface properties (lipophilicity and signal stability) was investigated and confirmed using surface-wetting characterization, SEM-EDS mapping and potentiometry. Principal component analysis (PCA) enabled discrimination among the bisphosphonates based on their lipophilicity and revealed distinct contributions of individual ISMs in both standard and commercial samples.