High speed DSC (hyper-DSC) as a tool to measure the solubility of a drug within a solid or semi-solid matrix.
Conventional differential scanning calorimetry (DSC) techniques are commonly used to quantify the solubility of drugs within polymeric-controlled delivery systems. However, the nature of the DSC experiment, and in particular the relatively slow heating rates employed, limit its use to the measurement of drug solubility at the drug's melting temperature. Here, we describe the application of hyper-DSC (HDSC), a variant of DSC involving extremely rapid heating rates, to the calculation of the solubility of a model drug, metronidazole, in silicone elastomer, and demonstrate that the faster heating rates permit the solubility to be calculated under non-equilibrium conditions such that the solubility better approximates that at the temperature of use. At a heating rate of 400 degrees C/min (HDSC), metronidazole solubility was calculated to be 2.16 mg/g compared with 6.16 mg/g at 20 degrees C/min.
Gramaglia
Daniela
D
Department of Pharmaceutical Chemistry, University of Pavia, Via Taramelli 12, 27100 Pavia, Italy.
Conway
Barbara R
BR
Kett
Vicky L
VL
Malcolm
R Karl
RK
Batchelor
Hannah K
HK
D002152:Calorimetry, Differential Scanning / Q000295:instrumentation*; D002626:Chemistry, Pharmaceutical / Q000295:instrumentation*; D005079:Excipients; D007202:Indicators and Reagents; D008567:Membranes, Artificial; D008795:Metronidazole / Q000737:chemistry; D012826:Silicone Elastomers; D012995:Solubility; D013696:Temperature
D005079:Excipients; D007202:Indicators and Reagents; D008567:Membranes, Artificial; D012826:Silicone Elastomers; D008795:Metronidazole