Development, characterization and evaluation of the dissolution profile of sulfasalazine suspensions

This paper reports the development, characterization and in vitrodissolution behavior of sulfasalazine suspensions for treatment of chronic intestinal inflammatory diseases. Three formulations were developed, from powdered sulfasalazine obtained from different suppliers. The sulfasalazine was characterized regarding concentration, Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), X-Ray Diffraction (XRD), particle size distribution, polydispersion and solubility. The suspensions were developed and characterized regarding pH, viscosity, density, particle size, sedimentation volume, concentration and dissolution. The pH values were slightly acidic. The method of preparing the suspensions reduced the particle sizes and made the size distribution more homogeneous. The dissolution studies showed that the sulfasalazine suspensions had low solubility in acidic media, but dissolve quickly, reaching levels of 85%, in neutral media or media containing 0.5% of surfactants such as polysorbate 80. Besides this, the sulfasalazine suspensions were classified as having immediate dissolution because they reached dissolution levels near 100% in 20 minutes.</p

Basic considerations in the dermatokinetics of topical formulations

Assessing the bioavailability of drug molecules at the site of action provides better insight into the efficiency of a dosage form. However, determining drug concentration in the skin layers following topical application of dermatological formulations is a great challenge. The protocols followed in oral formulations could not be applied for topical dosage forms. The regulatory agencies are considering several possible approaches such as tape stripping, microdialysis etc. On the other hand, the skin bioavailability assessment of xenobiotics is equally important for topical formulations in order to evaluate the toxicity. It is always possible that drug molecules applied on the skin surface may transport thorough the skin and reaches systemic circulation. Thus the real time measurement of molecules in the skin layer has become obligatory. In the last two decades, quite a few investigations have been carried out to assess the skin bioavailability and toxicity of topical/dermatological products. This review provides current understanding on the basics of dermatokinetics, drug depot formation, skin metabolism and clearance of drug molecules from the skin layers following application of topical formulations

Workshop report: USP workshop on exploring the science of drug absorption

In October 2018, the United States Pharmacopeia (USP) hosted a two-day workshop to explore the science of drug absorption. Experts from around the globe presented some of the challenges associated with drug product development from the perspective of the physiological attributes of the patient (human or canine) and the body site for drug activity. Included in the discussions were methods and approaches for answering complex questions, providing insights into the strengths and challenges of methods available in our biopharmaceutical tool chest. The following is a synopsis of the presentations and the highlights of the discussions that ensued. Disclaimer: This article reflects the views of the authors and should not be construed as representing the views or policies of the United States Food and Drug Administration. © 2019, Dissolution Technologies Inc. All rights reserved