Process-induced crystallite size and dissolution changes elucidated by a variety of analytical methods

Surfactant Free Preparation of Celecoxib Microcrystals by a Controlled Precipitation Process

“…XRD patterns show that the peaks of the micronized CLX are broader than those of the untreated CLX. This may be attributed to smaller particle size of the micronized CLX compared to untreated sample, 33 which was confirmed with the SEM photomicrographs. FTIR spectra between untreated and microsized CLX are identical, which demonstrated that the whole preparation process did not influence the chemistry composition of CLX.…”

Physicochemical and Atomic Characterization of Silver Powder after Biofield Treatment

“…Furthermore, it is demonstrated that the rate of dissolution of a drug can be improved by choosing solids which exhibits high solubility due to low crystallinity or high amorphous phase [31]. Torrado et al reported that solids with smaller crystallite size exhibited faster dissolution rate as compared to solids with higher crystallite size [32]. Thus, it is assumed that biofield treated silver powder may exhibit the higher dissolution rate in body fluid as compared to control, which ultimately can improve the bioavailability of dosage form containing silver.…”

Characterization of Physical State of Mannitol after Freeze-Drying: Effect of Acetylsalicylic Acid as a Second Crystalline Cosolute.

“…These processes can lead to modifications of the initial crystalline form of the drug. 4,5,8,9) The effects of freezing rate, temperature and mannitol concentration may also induce crystallographic changes producing a previously known mannitol form.6,7) Yu et al have shown that mixtures of d (major) and b (minor) polymorphs were produced by freeze-drying a 4% w/v pure mannitol solution.7) Nevertheless, other authors when employing a fast freezing process favored the formation of b form when 5% (w/v) mannitol solution was freezedried.6) The difficulties which arise when attending to control these variables (as temperature and cooling rate) during the freeze-drying process are shown by Yu et al,7) who identify several factors that can contribute to the vial-to-vial variation in the amount and stability of the mannitol hydrate.In the current study, acetylsalicylic acid (AAS) is used as model crystalline drug. Possible changes in crystallinity of AAS can be easily detected because its crystallographic characteristics are well known.…”

“…

When two different substances are mixed in a solution and then freeze-dried, some physical changes can affect the crystallographic characteristics of the final product.2,3) Pikal et al have reported the mutual inhibition of crystallization of mannitol and glycine during lyophilization.3) However, there are not many articles which study the effect of a crystalline active substance on the physical state of mannitol forms.Mannitol is an excipient broadly used in the freeze-drying process, [4][5][6][7][8] and its crystalline and amorphous forms have been extensively studied. 4,[6][7][8] The freeze-drying process can produce a partially amorphous and partially crystalline material 6) ; the crystallization of mannitol during this process can lead to different anhydrous polymorphs (a, b, and d).

…”

“…Mannitol is an excipient broadly used in the freeze-drying process, [4][5][6][7][8] and its crystalline and amorphous forms have been extensively studied. 4,[6][7][8] The freeze-drying process can produce a partially amorphous and partially crystalline material 6) ; the crystallization of mannitol during this process can lead to different anhydrous polymorphs (a, b, and d).…”