Publications by authors named "Maciej Gajda"

Mathematical models that treat the fed stomach content as a uniform entity emptied with a constant rate may not suffice to explain pharmacokinetic profiles recorded in clinical trials. In reality, phenomena such as the Magenstrasse or chyme areas of different pH and viscosity, play an important role in the intragastric drug dissolution and its transfer to the intestine. In this study, we investigated the data gathered in the bioequivalence trial between an immediate-release tablet (Reference) and an orally dispersible tablet (Test) with a poorly soluble weak base drug administered with or without water after a high-fat high-calorie breakfast.

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Novel calcium phosphate-based starter pellets were used to develop a biphasic-release multiple-unit pellet system (MUPS) with diclofenac sodium as a model drug in the form of hard gelatin capsules. For comparative purposes, corresponding formulations based on the inert cores made of microcrystalline cellulose, sucrose and isomalt were prepared. The developed system consisted of two types of drug-layered pellets attaining different release patterns: delayed-release (enteric-coated) and extended-release.

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The crystallisation of metastable drug polymorphs in polymer matrices has been reported as a successful approach to enhance the solubility of poorly water-soluble drug molecules. This can be achieved using different polymers, drug to polymer ratios and formulation techniques enabling the formation of stable nuclei and subsequent growth of new or metastable drug polymorphs. In this work we elucidated the polymorphism behaviour of a model compound fluconazole (FLU) embedded in solid dispersions with amorphous Soluplus (SOL) obtained using spray drying and fusion methods.

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Article Synopsis
  • Polymer-assisted cocrystallisation using hot melt extrusion (HME) enhances cocrystal yield compared to processing cocrystal components on their own, making it an effective one-step method for pharmaceutical synthesis.
  • This study investigates the influence of different types of polymers, specifically semicrystalline Poloxamer P407 (PXM) and amorphous Soluplus® (SOL), on the cocrystallisation of theophylline-nicotinamide (TP:NA) cocrystal that has distinct melting points.
  • Adding PXM during HME resulted in a more efficient cocrystal formation within the polymer matrix, while processing with SOL led to cocrystal formation either within an amorphous polymer matrix or as partially amorph
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Use of hot melt extrusion (HME) as continuous manufacturing process in the cocrystal synthesis is of increasing interest from both industrial and academic perspective and it is seen as a newly developing branch of mechanochemistry with possible broad application in single step synthesis and formulation of pharmaceutical cocrystals. Furthermore, one-step formulation of pharmaceutical products results in combined processing of pharmaceutical cocrystal mixtures with polymers using HME, which may result in phase change or formation of amorphous solid dispersions during the material processing. The manuscript aims at providing selection guidelines and understanding of processing parameters and instrumental setup of importance to design the HME process for cocrystal synthesis.

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Solid-state synthesis of pharmaceutical cocrystals is of contemporary interest as it offers an efficient way to modify the physicochemical properties of Active Pharmaceutical Ingredient (API) including its melting point, solubility, compressibility or physical stability, without compromising its structural integrity and bioactivity. Therefore, research of novel and emerging techniques for solvent-free, continuous and scalable methods for cocrystal formation is of paramount importance for further industrial development. In this work we form a basis for knowledge-based synthesis and formulation of model pharmaceutical cocrystal (flufenamic acid, FFA: nicotinamide, NA; 1:1) via matrix-assisted cocrystallisation (MAC) using Hot Melt Extrusion (HME).

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The thermal decomposition and kinetic parameters of synthetized imatinib mesylate α form α form were determined by thermogravimetry (TGA/DTG) under non-isothermal conditions. The experiments were performed at a 25-940°C temperature range at five different heating rates: 2.5Kmin(-1), 5Kmin(-1), 10Kmin(-1), 15Kmin(-1) and 20Kmin(-1) per minute in a nitrogen atmosphere.

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This paper describes hitherto developed drug forms for topical ocular administration, that is, eye drops, ointments, in situ gels, inserts, multicompartment drug delivery systems, and ophthalmic drug forms with bioadhesive properties. Heretofore, many studies have demonstrated that new and more complex ophthalmic drug forms exhibit advantage over traditional ones and are able to increase the bioavailability of the active substance by, among others, reducing the susceptibility of drug forms to defense mechanisms of the human eye, extending contact time of drug with the cornea, increasing the penetration through the complex anatomical structure of the eye, and providing controlled release of drugs into the eye tissues, which allows reducing the drug application frequency. The rest of the paper describes recommended in vitro and in vivo studies to be performed for various ophthalmic drugs forms in order to assess whether the form is acceptable from the perspective of desired properties and patient's compliance.

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