RESUMO
In this paper we discuss the link between the domain of physical parameters - molecular descriptors of a drug, and terahertz (THz) spectra. We measured the derivatives of the well-known anti-inflammatory drug Piroxicam using THz spectroscopy and employed Principal Component Analysis to build similarity maps in the molecular descriptor and spectral domains. We observed, that the spatial neighborhood on the molecular descriptors map is highly correlated with the spectral neighbourhood within a group of structurally-similar molecules. We built a Partial Least Squares (PLS) predictive model to quantify the relationship between the spectra and the melting point, which can guide the selection of early drug candidates.
Assuntos
Desenvolvimento de Medicamentos/métodos , Espectroscopia Terahertz/métodos , Anti-Inflamatórios/química , Análise dos Mínimos Quadrados , Piroxicam/química , Análise de Componente PrincipalRESUMO
THz-TDS techniques are applied to investigate selected pharmaceutical samples. Investigations were performed on selected pharmaceutical samples with active pharmaceutical ingredients (API)--famotidine, ranitidine, fenofibrate, lovastatin, simvastatin, aspirin, ketoconazole, acyclovir (hydrated and non-hydrated), on excipients--lactose, glucose (hydrated and non-hydrated), Pluronic 127, and on mixtures of selected compounds. Pseudo-polymorphism effects are considered as well. Examples of the terahertz imaging technique are also given. APIs and excipients can be easily recognized in the terahertz band by their specific "fingerprints" as individual components and in mixtures. The hydration process as a variety of polymorphism can also be easily monitored using the THz technique. Moreover, terahertz light can be useful for the penetration of tablets, giving clear pictures of possible defects in tablet coatings.
Assuntos
Preparações Farmacêuticas/análise , Espectroscopia Terahertz/métodos , Excipientes/análise , ComprimidosRESUMO
In the paper, Fourier transform has been used for calculations of a refractive index of dielectric samples measured in the terahertz photomixer arrangement. We considered measurement limitations caused by a sampling frequency and a photomixer bandwidth.
