title: Mechanistic study of carvacrol processing and stabilization as glassy solid solution and microcapsule.
abstract: Essential oils and other liquid active pharmaceutical ingredients (APIs) are frequently microencapsulated to improve shelf life, handling, and for tailoring release. A glassy solid solution (GSS), a single-phase system, where the excipient is plasticized by the API, could be an alternative formulation system. Thus this study focuses on the investigation of two formulation strategies using carvacrol as a model compound, namely a microcapsule (MC) and a glassy solid solution (GSS). Applying the solubility parameter approach, polyvinylpyrrolidone (PVP) was chosen as a suitable matrix material for a GSS system, whereas maltodextrin and sucrose served as excipients for a microcapsule (MC) system. Differential scanning calorimetry (DSC) measurements of the excipients' glass transition temperatures and the melting point of carvacrol verified plasticizing properties of carvacrol on PVP. Batch mixing processes, as preliminary experiments for future extrusion processes, were performed to prepare GSSs and MCs with various amounts of carvacrol, followed by crushing and sieving. Maximally 4.5% carvacrol was encapsulated in the carbohydrate material, whereas up to 16.3% were stabilized as GSS, which is an outstanding amount. However, grinding of the samples led to a loss of up to 30% of carvacrol.
authors.affiliation: Institute of Process Engineering in Life Sciences, Section I: Food Process Engineering, Karlsruhe Institute of Technology, Karlsruhe, Germany; Institute of Pharmaceutics and Biopharmaceutics, Heinrich-Heine-University, Duesseldorf, Germany. Electronic address: markus.tackenberg@hhu.de.
authors.forename: Markus W
authors.initials: MW
authors.lastname: Tackenberg
authors.affiliation: Institute of Process Engineering in Life Sciences, Section I: Food Process Engineering, Karlsruhe Institute of Technology, Karlsruhe, Germany. Electronic address: carola_geisthoevel@web.de.
authors.forename: Carola
authors.initials: C
authors.lastname: Geisthövel
authors.affiliation: Institute of Pharmaceutical Biology and Biotechnology, Heinrich-Heine-University, Duesseldorf, Germany. Electronic address: andreas.marmann@hhu.de.
authors.forename: Andreas
authors.initials: A
authors.lastname: Marmann
authors.affiliation: Institute of Process Engineering in Life Sciences, Section I: Food Process Engineering, Karlsruhe Institute of Technology, Karlsruhe, Germany. Electronic address: heike.schuchmann@kit.edu.
authors.forename: Heike P
authors.initials: HP
authors.lastname: Schuchmann
authors.affiliation: Institute of Pharmaceutics and Biopharmaceutics, Heinrich-Heine-University, Duesseldorf, Germany. Electronic address: kleinebudde@hhu.de.
authors.forename: Peter
authors.initials: P
authors.lastname: Kleinebudde
authors.affiliation: Institute of Pharmaceutics and Biopharmaceutics, Heinrich-Heine-University, Duesseldorf, Germany. Electronic address: markus.thommes@hhu.de.
authors.forename: Markus
authors.initials: M
authors.lastname: Thommes
mesh_terms: D002152:Calorimetry, Differential Scanning; D002214:Capsules; D002241:Carbohydrates / Q000737:chemistry; D000081007:Cymenes; D004355:Drug Stability; D005079:Excipients / Q000737:chemistry*; D039821:Monoterpenes / Q000737:chemistry*; D011092:Polyethylene Glycols / Q000737:chemistry; D011095:Polyethylenes / Q000737:chemistry; D011109:Polymethacrylic Acids / Q000737:chemistry; D011126:Polypropylenes / Q000737:chemistry; D011205:Povidone / Q000737:chemistry*; D012996:Solutions; D014867:Water / Q000737:chemistry
chemical_list: D002214:Capsules; D002241:Carbohydrates; D000081007:Cymenes; D005079:Excipients; C510078:Lutrol F 127; D039821:Monoterpenes; D011095:Polyethylenes; D011109:Polymethacrylic Acids; D011126:Polypropylenes; D012996:Solutions; D014867:Water; C038300:methylmethacrylate-methacrylic acid copolymer; D011092:Polyethylene Glycols; C073316:carvacrol; D011205:Povidone
keywords: Carbohydrates; Carvacrol; Carvacrol (PubChem CID: 10364); Glassy solid solution; Maltodextrin (PubChem CID: 107526); Methylene chloride (PubChem CID: 66344); Microencapsulation; PVP; Plasticization; Polyvinylpyrrolidone (PubChem CID: 6917); Sodium hydroxide (PubChem CID: 14798); Sucrose (PubChem CID: 5988)