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Traditional eye drops used for topically administering drugs have poor ocular bioavailability due to the biological barriers of the eye. There is an interest to design and develop novel drug delivery systems that would extend the precorneal residence time, reduce the frequency of administration and decrease dose-related toxicity. This study aimed to prepare Nanoparticles of Gemifloxacin Mesylate and incorporate them into an in situ gel. The nanoparticles were prepared by ionic gelation technique, using 32 factorial design. Sodium tripolyphosphate (STPP) was used to crosslink Chitosan. The optimized formulation of the nanoparticles (GF4) contained 0.15% Gemifloxacin Mesylate, 0.15% Chitosan and 0.20% STPP, producing 71 nm particle size and 81.11% entrapment efficiency. The prepared nanoparticles showed biphasic release, with an initial burst release of 15% in 1.0 hr and a cumulative drug release of 90.53% at the end of 24 hrs. After that, the prepared nanoparticles were incorporated into an in situ gel, using Poloxamer 407, producing a sustained drug release with efficient antimicrobial activity against gram-positive and gram-negative bacteria as confirmed by the cup plate method. [ABSTRACT FROM AUTHOR]

A drug-excipient interaction impurity associated with the degradation process of pramipexole was isolated. The impurity was detected during the stability study of pramipexole extended-release tablets. It was found at a relative retention time of 0.88 with respect to pramipexole, using the pramipexole gradient HPLC-UV detection method described in the USP. The structure of the impurity was identified and fully characterized using high resolution mass spectrometry, IR and NMR techniques, as presented herein. The degradation impurity was identified as (S)-N2-(methoxymethyl)-N6-propyl-4,5,6,7-tetrahydro-1,3-benzothiazole-2,6-diamine. The drug-excipient interaction mechanism of its formation was proposed. An efficient and straightforward synthetic approach was developed to prepare the degradation impurity to confirm its proposed degradation pathway and structure. [ABSTRACT FROM AUTHOR]