Polymorphism and kinetic behavior of binary mixtures of triglycerides

Pattarino, Franco; Bettini, Ruggero; Bonda, Andrea Foglio; Bella, Andrea Della; Giovannelli, Lorella

doi:10.1016/j.ijpharm.2014.06.042

Cited by 13 publications

(7 citation statements)

References 24 publications

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“…The DSC thermograms are depicted in Figure S2 . The observed results are in close agreement with previously reported data for pure GMS (see Supplementary Materials for an in-deep analysis) [ 43 , 44 , 45 , 46 , 47 , 48 ]. Addition of a short-chain triglyceride, such as triacetin, can hinder rearrangement into densely packed lattices, thus avoiding premature drug expulsion from the NLC [ 25 , 49 ].…”

Section: Resultssupporting

confidence: 93%

Nanostructured Lipid Carriers for Enhanced Transscleral Delivery of Dexamethasone Acetate: Development, Ex Vivo Characterization and Multiphoton Microscopy Studies

et al. 2023

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Corticosteroids, although highly effective for the treatment of both anterior and posterior ocular segment inflammation, still nowadays struggle for effective drug delivery due to their poor solubilization capabilities in water. This research work aims to develop nanostructured lipid carriers (NLC) intended for periocular administration of dexamethasone acetate to the posterior segment of the eye. Pre-formulation studies were initially performed to find solid and liquid lipid mixtures for dexamethasone acetate solubilization. Pseudoternary diagrams at 65 °C were constructed to select the best surfactant based on the macroscopic transparency and microscopic isotropy of the systems. The resulting NLC, obtained following an organic solvent-free methodology, was composed of triacetin, Imwitor® 491 (glycerol monostearate >90%) and tyloxapol with Z-average = 106.9 ± 1.2 nm, PDI = 0.104 ± 0.019 and zeta potential = −6.51 ± 0.575 mV. Ex vivo porcine sclera and choroid permeation studies revealed a considerable metabolism in the sclera of dexamethasone acetate into free dexamethasone, which demonstrated higher permeation capabilities across both tissues. In addition, the NLC behavior once applied onto the sclera was further studied by means of multiphoton microscopy by loading the NLC with the fluorescent probe Nile red.

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Section: Resultssupporting

confidence: 93%

Nanostructured Lipid Carriers for Enhanced Transscleral Delivery of Dexamethasone Acetate: Development, Ex Vivo Characterization and Multiphoton Microscopy Studies

et al. 2023

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“…To the best of our knowledge, the only paper suggesting the use of additives for stabilizing the stable β-form of solid triglyceride-based formulations was that of Pattarino et al [ 30 ]. In that study, small amounts of medium-chain liquid triglyceride (MCT) added to tristearin-based systems promoted the formation of the stable β-form.…”

Section: Introductionmentioning

confidence: 99%

Liquid Lipids Act as Polymorphic Modifiers of Tristearin-Based Formulations Produced by Melting Technologies

2021

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Despite the growing interest in lipid-based formulations, their polymorphism is still a challenge in the pharmaceutical industry. Understanding and controlling the polymorphic behavior of lipids is a key element for achieving the quality and preventing stability issues. This study aims to evaluate the impact of different oral-approved liquid lipids (LL) on the polymorphism, phase transitions and structure of solid lipid-based formulations and explore their influence on drug release. The LL investigated were isopropyl myristate, ethyl oleate, oleic acid, medium chain trigycerides, vitamin E acetate, glyceryl monooleate, lecithin and sorbitane monooleate. Spray-congealing was selected as an example of a melting-based solvent-free manufacturing method to produce microparticles (MPs) of tristearin (Dynasan®118). During the production process, tristearin MPs crystallized in the metastable α-form. Stability studied evidenced a slow phase transition to the stable β-polymorph overtime, with the presence of the α-form still detected after 60 days of storage at 25 °C. The addition of 10% w/w of LL promoted the transition of tristearin from the α-form to the stable β-form with a kinetic varying from few minutes to days, depending on the specific LL. The combination of various techniques (DSC, X-ray diffraction analysis, Hot-stage polarized light microscopy, SEM) showed that the addition of LL significantly modified the crystal structure of tristearin-based formulations at different length scales. Both the polymorphic form and the LL addition had a strong influence on the release behavior of a model hydrophilic drug (caffeine). Overall, the addition of LL can be considered an interesting approach to control triglyceride crystallization in the β-form. From the industrial viewpoint, this approach might be advantageous as any polymorphic change will be complete before storage, hence enabling the production of stable lipid formulations.

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“…For hydrocarbon systems, studies include measurement and modelling of equilibrium solubilities in alkane mixtures [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21], alkane crystal nucleation and growth kinetics [22][23][24][25] and alkane crystal gel formation [1-3, 26, 27]. Relevant literature on TAG systems includes TAG polymorphism [28][29][30] and relation to solubility [31], TAG crystallisation (reviews [32][33][34] and specific TAG systems [35][36][37][38][39][40]) and fat crystal network and pour point properties [4,5,41]. Most practical applications involve systems containing either mixed hydrocarbon wax solutes in a mixed hydrocarbon solvent or mixed TAG solutes in a mixed TAG solvent.…”

Section: Introductionmentioning

confidence: 99%

“…Figure 2.XRD plots for SSS crystals measured for three samples ("as received", as extracted from a 10 wt% solution upon cooling just below Tcool at 0.5 o C/min (denoted "0.5 o C/min") and as extracted from a 10 wt% solution cooled at 2.0 o C/min to 1.0 o C above Tcool and held for three hours prior to extraction (denoted "Held above Tcool")) and compared to literature data[40,46]. The vertical solid lines indicate the major peak positions for the β polymorph; the vertical dotted line corresponds to the major peak for the α polymorph (absent) and the vertical dashed lines correspond to the β´ polymorph (absent).…”

mentioning

confidence: 99%

Solubility behaviour, crystallisation kinetics and pour point: A comparison of linear alkane and triacyl glyceride solute/solvent mixtures

Fletcher

Roberts

Urquhart

2016

Journal of Industrial and Engineering Chemistry

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Mixtures of either a hydrocarbon wax in a hydrocarbon solvent or a long chain triacyl glyceride (TAG) in a TAG solvent show complex solubility boundary temperature hysteresis and precipitated crystal network formation leading to gelation. For these industrially-important systems, we show how the equilibrium solubility and its hysteresis, crystallisation kinetics and pour point temperature vary with solute concentration for representative examples of both hydrocarbon (n-tetracosane (C24) solute in n-heptane (C7) solvent) and TAG (tristearin (SSS) solute in tricaprylin (CCC) solvent) mixtures. The behaviour is modelled with good accuracy; thereby providing a useful aid to formulation and process optimisation.

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Polymorphism and kinetic behavior of binary mixtures of triglycerides

Cited by 13 publications

References 24 publications

Nanostructured Lipid Carriers for Enhanced Transscleral Delivery of Dexamethasone Acetate: Development, Ex Vivo Characterization and Multiphoton Microscopy Studies

Nanostructured Lipid Carriers for Enhanced Transscleral Delivery of Dexamethasone Acetate: Development, Ex Vivo Characterization and Multiphoton Microscopy Studies

Liquid Lipids Act as Polymorphic Modifiers of Tristearin-Based Formulations Produced by Melting Technologies

Solubility behaviour, crystallisation kinetics and pour point: A comparison of linear alkane and triacyl glyceride solute/solvent mixtures

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