Variable Effects of Twenty Sugars and Sugar Alcohols on the Retrogradation of Wheat Starch Gels

Starch retrogradation is desirable for some food textures and nutritional traits but detrimental to sensory and storage qualities of other foods. The objective of this study was to determine the impact of sweetener structure and concentration on the retrogradation of wheat starch gels. The effects of 20 sweeteners selected based on common food usage and stereochemical structures of interest, and ranging in concentration from 10 to 50%w/w, on the retrogradation of wheat starch gels were monitored spectrophotometrically over time. The sweeteners were sucrose, xylose, ribose, glucose, galactose, fructose, mannose, mannitol, L-sorbose, xylitol, tagatose, allulose, maltose, lactose, isomaltulose, isomalt, sorbitol, maltitol, and raffinose. Retrogradation rates and amounts were compared by Avrami equation rate constants (k = 0.1–0.7) and absorbance values measured on day 28 (Abs = 0.1–1.0), respectively. Both sweetener concentration and type significantly affected retrogradation. Gels made with sugar alcohols and high sweetener concentrations (≈≥40%) tended to retrograde more and faster, whereas gels made with sugars and low sweetener concentrations tended to have lower retrogradation rates and amounts. Sweeteners with more equatorial and exocyclic hydroxyl groups (e.g., glucose and maltitol) and those with larger molar volumes (e.g., isomaltulose and raffinose) tended to increase the rate and amount of retrogradation, particularly at higher concentrations. The impact of sweeteners on retrogradation was a balance of factors that promoted retrogradation (intermolecular interactions and residual short-range molecular order) and inhibiting behaviors (interference at crystallization sites), which are influenced by sweetener concentration and structure. Understanding which sweeteners at which concentrations can be used to promote or inhibit retrogradation is useful for product formulation strategies.

Proniosomal Microcarriers: Impact of Constituents on the Physicochemical Properties of Proniosomes as a New Approach to Enhance Inhalation Efficiency of Dry Powder Inhalers

Proniosomes are free-flowing systems with coating carriers, which developed as a method for improving the drug flow and pulmonary delivery. Extensive research on proniosomes was done to enhance the dry powder inhalers (DPI)'s inhalation performance. This research aimed at studying the impact of lactose-mannitol mixture additives on the proniosome's physicochemical properties as a method for improving the inhalation efficiency of DPI. Vismodegib has been employed as a compound model. Box-Behnken design has been employed to prepare different proniosomes formulae by incorporating various (A) span 60 concentrations, (B) lactose concentrations and (C) mannitol: total carrier mixture. The measured responses were vesicle size (R₁), %release (R₂), Carr's index (R₃) and %recovery (R₄). The results displayed that R₁ and R₄ were significantly antagonistic to C and significantly synergistic to both A and B while R₂ and R₃ were significantly synergistic to C and significantly antagonistic to both A and B. The optimal formula was selected for its aerodynamic behaviour, cytotoxic activity and bioavailability assessment. The optimal formula resulted in better Vismodegib lung deposition, cytotoxic activity and relative bioavailability. This novel formula could be a promising carrier for sustained delivery of drugs via the pulmonary route.

The effect of engineered mannitol-lactose mixture on dry powder inhaler performance

PURPOSE

To co-crystallise mannitol and lactose with a view to obtaining crystals with more favourable morphological features than either lactose or mannitol alone, suitable for use as carriers in formulations for dry powder inhalers (DPIs) using simultaneous engineering of lactose-mannitol mixtures.

METHODS

Mannitol and lactose individually and the two sugars with three different ratios were crystallised/co-crystallised using anti-solvent precipitation technique. Obtained crystals were sieved to separate 63-90 μm size fractions and then characterised by size, shape, density and in vitro aerosolisation performance. Solid state of crystallized samples was studied using FT-IR, XRPD and DSC.

RESULTS

At unequal ratios of mannitol to lactose, the elongated shape dominated in the crystallisation process. However, lactose exerted an opposite effect to that of mannitol by reducing elongation ratio and increasing the crystals' width and thickness. Crystallised β-lactose showed different anomers compared to commercial lactose (α-lactose monohydrate). Crystallised α-mannitol showed different polymorphic form compared to commercial mannitol (β-mannitol). Crystallised mannitol:lactose showed up to 5 transitions corresponding to α-mannitol, α-lactose monohydrate, β-lactose, 5α-/3β-lactose and 4α-/1β-lactose. In vitro deposition assessments showed that crystallised carriers produced more efficient delivery of salbutamol sulphate compared to formulations containing commercial grade carriers.

CONCLUSION

The simultaneous crystallization of lactose-mannitol can be used as a new approach to improve the performance of DPI formulations.