Fatty acid polymorph identification by infrared

Bailey, A. V.; Mitcham, Donald; Pittman, Robert A.; Sumrell, Gene

doi:10.1007/bf02582525

Cited by 25 publications

(7 citation statements)

References 6 publications

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“…In Figure 9a, only one pronounced melting point peak of unprocessed SA at 57.3 °C was observed, different from literature of 69.6 °C of pure SA. Of course the same result with our study was presented for thermal behavior and melting point of unprocessed SA by Pawara 34 and by Ribeiro 35 .…”

Section: Dsc Analysis: Differential Scanning Calorimetry Is a Suitablsupporting

confidence: 90%

“…The C polymorphic form shows a single strong IR band at 937 cm -1 corresponding to the OH bending vibration band of the carboxyl group. Consequently, comparison of the FT-IR spectrum and XRD pattern of processed and unprocessed stearic acid ( Figure 6, 7 and 8) with the published FT-IR spectrum of different polymorphic forms of stearic acid 34 indicates that the crystal structure was unchanged and confirmed to be as polymorph form C before and after the RESS process.…”

Section: Fig 7: Ft-ir Analysis Of Unprocessed Stearic Acid Particles mentioning

confidence: 93%

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2014

IJPSR

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Rapid expansion of supercritical solution (RESS) has provided a promising alternative to produce ultrafine particles of heatsensitive materials. Stearic acid is a good lipid for development of solid lipid nanoparticles (SLNs) in drug delivery systems. Therefore, currently, much research on the micronization of stearic acid is going on. In this study, formation of submicron stearic acid was reported by using RESS process. Thanks to high solubility of stearic acid in supercritical CO2, RESS can be used to produce stearic acid nanoparticles and so in this process, extraction temperature and pressure are a bit more than critical point of SC-CO2. The unprocessed and processed stearic acid powders were characterized by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and Fourier transform infrared spectrophotometry (FT-IR). FT-IR analysis and XRD pattern of processed stearic acid showed that the degree of crystallinity was reduced without any chemical structural change. DSC analysis showed a 2.7•C decrease in the melting point from that of bulk stearic acid. Also, the RESS processing of stearic acid leads to spherical particles in the range from40nm to 200 nm which are about 600 times smaller than the unprocessed powder as reflected by SEM observations.

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Section: Dsc Analysis: Differential Scanning Calorimetry Is a Suitablsupporting

confidence: 90%

Section: Fig 7: Ft-ir Analysis Of Unprocessed Stearic Acid Particles mentioning

confidence: 93%

Untitled

2014

IJPSR

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“…Polymorphic forms of stearic acid described in literature are: A form, B form, C form and E form. 6 Among the various polymorphic forms of stearic acid, C form is the most stable one. B form has hydrogen bond distance of 2.4 A whereas C form has 2.6 A. Stearic acid has orthorhombic packing with a molecular packing coefficient of 0.701 for B form and 0.690 for C form.…”

Section: Introductionmentioning

confidence: 99%

“…7 The melting point of stearic acid is 69.6 C. 8 As the melting point of stearic acid is much higher than human body temperature, it could be used as a lipid matrix material in nanoparticles. 6,9,10 SLNs of stearic acid can be prepared by using anionic surfactants such as taurocholate. 9 However, these SLNs cannot be prepared without using a co-surfactant.…”

Section: Introductionmentioning

confidence: 99%

Solid lipid nanoparticles of stearic acid for the drug delivery of paliperidone

Kumar

Randhawa

2015

RSC Adv.

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ABSTRARTPaliperidone is an antipsychotic drug having poor water solubility and bioavailability. Solid lipid nanoparticles of stearic acid loaded with paliperidone was prepared to enhance the bioavailability. Spherical nanoparticles of stearic acid containing paliperidone was prepared with the surfactant, biz. Gelucire® 50/13 forming a stabilizing layer over the nanoparticles. Particle size of the SLNs was found to exponentially decrease with the increase in the surfactant concentration. Dynamic light scattering (DLS), transmission electron 10 microscopy (TEM) and atomic force microscopy (AFM) imaging revealed that the average particle size of SLNs was 230±30 nm. Fourier transform infra-red spectroscopy (FTIR), X-ray diffraction (XRD) and differential scanning calorimetry (DSC) analysis revealed that there was no chemical interaction between the ingredients of the SLNs. However, molecular dispersion of the paliperidone in the stearic acid matrix led to the reduction in crystallinity of stearic acid. The entrapment efficiency of paliperidone in the lipid was calculated as 42.4 (% w/w). The corresponding % drug loading was calculated as 4.1 (% w/w) of the total lipid content. Controlled 15 release pattern was observed in the invitro release kinetics studies. Invitro cell culture studies against RAW 264.7 murine macrophages revealed that the paliperidone loaded SLNs have some cytotoxicity. But the observed toxicity was not concentration dependent as there was at least 60 % viability of the cells in the concentration range of 30 -120 µg/ml.

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“…Bailey et al (2) first pointed out the differences in solubility of the stearic acid polymorphs. In a following paper (3) théy pointed out that the C polymorph is stable above 40 °C and the B polymorph below 40 °C. Below 10 °C they suspect the E form to be stable.…”

Section: Introductionmentioning

confidence: 99%

Solubility of the A, B, and C polymorphs of stearic acid in decane, methanol, and butanone

Beckmann¹,

Boistelle²,

Sato³

1984

J. Chem. Eng. Data

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The solublllty of the A, B, and C polymorphs of stearlc acid Is measured In decane, butanone, and methanol. The experlments were carried out between 6 and 38, -2 and 39, and 8 and 33 OC for decane, methanol, and butanone, respectlvely. The enthalpies and entroples of dlssolutlon for decane and butanone agree well with those derlved from fuslon data. The enthalples check with those dlrectly determlned by calorlmetry. The entroples for the polymorphic transltlons B-C and A-C are found as 4.6 f 0.5 and 1.3 f 0.7 kJ mol-', respectlvely. The stablllty reglons of the polymorphs are deduced wlthln 2 K. The B and C polymorphs coexlst at 29 OC; B Is stable below thls temperature whereas C I s stable above It. The A polymorph Is unstable at all temperatures. As an example, at 25 OC, the solublllty of the B polymorph In 100 g of solvent Is 0.698, 1.608, and 4.575 g for decane, methanol, and butanone, respectlvely. Introductlon I n some respects stearic acid, CH3(CH,),&OOH, is an interesting substance to investigate the solubility of different polymorphic modifications: (i) the different modifications can be separately crystallized; (ii) the heats of polymorphic transformation are sufficiently high to give differences in solubility; (iii) the transitions between the polymorphs occur well below the melting point but are kinetically hindered, so that all polymorphs can be observed at the same temperature.Stearic acid mainly crystallizes from solution in three polymorphic modifications A, B, and C ( 7 ) . The B and C polymorphs are easily crystallized in lozenge-shaped, thin crystals, whereas the A polymorph forms needlelike crystals and is difficult to crystallize. Thus, we drew our attention to the B and C polymorphs, while only a few experiments were carried out with the A polymorph. Bailey et al.(2) first pointed out the differences in solubility of the stearic acid polymorphs. I n a following paper ( 3 ) they pointed out that the C polymorph is stable above 40 OC and the B polymorph below 40 OC. Below 10 OC they suspect the E form to be stable. This latter polymorph has nearly the same macroscopic crystallographic features as the B one. However, its occurrence conditions are not welldefined. No quantitative information about the differences in solubility was given (2, 3 ) .Solubilities for stearic acid are quite abundantly given in the literature. The data are nearly completely accumulated by Singleton (4). However, a closer examination shows a varying accuracy, which is often insufficient. Furthermore, the difference in solubility of the polymorphs is not quantitatively clarified. Since exact solubility data are needed for experiments concerning the crystallization of the B and C forms of stearic acid, we undertook careful measurements of the polymorph-specific solubility and selected decane, methanol, and butanone as solvents. ?On leave from the Institut fur Physikalische und Theoretische Chemie der TU, 0-3300 Braunschweig, West Germany. *On leave from the Faculty of Applied Biological Science, Hiroshima University, 2-17...

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Fatty acid polymorph identification by infrared

Cited by 25 publications

References 6 publications

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Solid lipid nanoparticles of stearic acid for the drug delivery of paliperidone

Solubility of the A, B, and C polymorphs of stearic acid in decane, methanol, and butanone

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