title: An optical method for continuous monitoring of the dissolution rate of pharmaceutical powders.
abstract: Monitoring systems providing fast and reliable, even on-line data, from a distinct process stage or final product are needed in drug development, from the early stages of drug discovery until the drug product manufacturing procedures. This includes also processes involving solid particles, such as drug dissolution. However, the existing in vitro drug dissolution test methods suffer limitations, such as long sampling times of 30-60s and thus the inability to be adapted to continuous monitoring, time consuming sample preparation and consumption of large amounts of reagents. In this study, an optical method for monitoring the dissolution rate of pharmaceutical powders was evaluated with model drugs having different dissolution rates. The measuring system consisted of a laser source, light detector, oscilloscope, magnetic stirrer and sample vessel. The intensity of laser light transmitted through the dissolution medium was recorded and displayed by the oscilloscope. Dissolution curves were produced by fitting the raw data with mathematical functions. The optical method was found to be resource-saving, reliable and capable of detecting differences in even rapid dissolution rates of drug compounds. This technique might have targets of application in real-time monitoring of processes in many different sectors, including the pharmaceutical industry.
authors.affiliation: School of Pharmacy, University of Eastern Finland, PO Box 1627, FI-70211, Kuopio, Finland. riikka.laitinen@uef.fi
authors.forename: Riikka
authors.initials: R
authors.lastname: Laitinen
authors.forename: Jani
authors.initials: J
authors.lastname: Lahtinen
authors.forename: Pertti
authors.initials: P
authors.lastname: Silfsten
authors.forename: Erik
authors.initials: E
authors.lastname: Vartiainen
authors.forename: Pekka
authors.initials: P
authors.lastname: Jarho
authors.forename: Jarkko
authors.initials: J
authors.lastname: Ketolainen
mesh_terms: D002626:Chemistry, Pharmaceutical / Q000379:methods*; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D007834:Lasers; D008027:Light; D004364:Pharmaceutical Preparations / Q000737:chemistry*; D011208:Powders / Q000737:chemistry*; D012542:Scattering, Radiation; D012995:Solubility; D013678:Technology, Pharmaceutical / Q000379:methods*; D013997:Time Factors
chemical_list: D004364:Pharmaceutical Preparations; D011208:Powders