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Open AccessArticle

Fluoroquinolone Amorphous Polymeric Salts and Dispersions for Veterinary Uses

1
School of Pharmacy and Pharmaceutical Sciences, Trinity College Dublin, College Green, 2 Dublin, Ireland
2
SSPC, Synthesis and Solid State Pharmaceutical Centre, Limerick, Ireland
3
MINT, UNIV Angers, INSERM 1066, CNRS 6021, Universite Bretagne Loire, 4 rue Larrey, CEDEX, 49933 Angers, France
*
Author to whom correspondence should be addressed.
Pharmaceutics 2019, 11(6), 268; https://doi.org/10.3390/pharmaceutics11060268
Received: 18 May 2019 / Revised: 3 June 2019 / Accepted: 6 June 2019 / Published: 9 June 2019
(This article belongs to the Special Issue Recent Progress in Solid Dispersion Technology)
Enrofloxacin (ENRO) is a poorly soluble drug used in veterinary medicine. It differs from the more widely used fluoroquinolone ciprofloxacin (CIP) by the presence of an ethyl substituent on its piperazine amino group. While a number of recent studies have examined amorphous composite formulations of CIP, little research has been conducted with ENRO in this area. Therefore, the main purpose of this work was to produce amorphous solid dispersions (ASDs) of ENRO. The solid-state properties of these samples were investigated and compared to those of the equivalent CIP ASDs, and their water uptake behavior, solubility, dissolution, and antibacterial activity were assessed. Like CIP, X-ray amorphous solid dispersions were obtained when ENRO was ball milled with acidic polymers, whereas the use of neutral polymers resulted in semi-crystalline products. Proton transfer from the carboxylic acids of the polymers to the tertiary amine of ENRO’s piperazine group appears to occur in the ASDs, resulting in an ionic bond between the two components. Therefore, these ASDs can be referred to as amorphous polymeric salts (APSs). The glass transition temperatures of the APSs were significantly higher than that of ENRO, and they were also resistant to crystallization when exposed to high humidity levels. Greater concentrations were achieved with the APSs than the pure drug during solubility and dissolution studies, and this enhancement was sustained for the duration of the experiments. In addition, the antimicrobial activity of ENRO was not affected by APS formation, while the minimum inhibitory concentrations and minimum bactericidal concentrations obtained with the APS containing hydroxypropyl methylcellulose acetate succinate grade MG (HPMCAS-MG) were significantly lower than those of the pure drug. Therefore, APS formation is one method of improving the pharmaceutical properties of this drug. View Full-Text
Keywords: enrofloxacin; ciprofloxacin; amorphous solid dispersion; amorphous polymeric salt; polymer; ball milling; solubility; dissolution enrofloxacin; ciprofloxacin; amorphous solid dispersion; amorphous polymeric salt; polymer; ball milling; solubility; dissolution
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MDPI and ACS Style

Mesallati, H.; Umerska, A.; Tajber, L. Fluoroquinolone Amorphous Polymeric Salts and Dispersions for Veterinary Uses. Pharmaceutics 2019, 11, 268.

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