5α-Dihydro­vespertilin acetate

In the title compound, C24H36O4 [systematic name: (20S)-3β-acet­oxy-16α-hydr­oxy-22,23-bis­nor-5α,17β-cholano(22-16)lac­tone], the three six-membered rings adopt classical chair conformations, while the five-membered rings are in envelope conformations. The ester group attached to ring A is in an equatorial position. Rings A/B, B/C and C/D are trans-fused, whereas rings D/E are cis-fused. The structure is devoid of any classical hydrogen bonds. However, non-classical inter- and intra­molecular hydrogen-bonding inter­actions of the type C—H⋯O are present in the structure

(E)-2-(2-Nitro­ethen­yl)furan

The title compound, C6H5NO3, was synthesized via condensation of furfural with nitro­methane in the presence of isobutyl­amine. The compound crystallizes exclusively as the E isomer. The angle between the mean planes of the furan ring and the nitro­alkenyl group is 1.3 (2)°

Evaluation of Three Amorphous Drug Delivery Technologies to Improve the Oral Absorption of Flubendazole

AbstractThis study investigates 3 amorphous technologies to improve the dissolution rate and oral bioavailability of flubendazole (FLU). The selected approaches are (1) a standard spray-dried dispersion with hydroxypropylmethylcellulose (HPMC) E5 or polyvinylpyrrolidone-vinyl acetate 64, both with Vitamin E d-α-tocopheryl polyethylene glycol succinate; (2) a modified process spray-dried dispersion (MPSDD) with either HPMC E3 or hydroxypropylmethylcellulose acetate succinate (HPMCAS-M); and (3) confining FLU in ordered mesoporous silica (OMS). The physicochemical stability and in vitro release of optimized formulations were evaluated following 2 weeks of open conditions at 25°C/60% relative humidity (RH) and 40°C/75% RH. All formulations remained amorphous at 25°C/60% RH. Only the MPSDD formulation containing HPMCAS-M and 3/7 (wt./wt.) FLU/OMS did not crystallize following 40°C/75% RH exposure. The OMS and MPSDD formulations contained the lowest and highest amount of hydrolyzed degradant, respectively. All formulations were dosed to rats at 20 mg/kg in suspension. One FLU/OMS formulation was also dosed as a capsule blend. Plasma concentration profiles were determined following a single dose. In vivo findings show that the OMS capsule and suspension resulted in the overall highest area under the curve and Cmax values, respectively. These results cross-evaluate various amorphous formulations and provide a link to enhanced biopharmaceutical performance

3-Deoxy-1,2-O-isopropylidene-3-C-methyl-5-O-(p-tolylsulfonyl)-D-ribofuranose

In the title compound [alternative name: (2,2,6R-trimethyltetrahydrofuro[ 2R,3R-d][1,3]dioxol-5S-yl)methyl 4-methylbenzenesulfonate], C16H22O6S, the ribo-pentofuranose ring is in the T (twisted) conformation, with atom C3 exo and atom C4 endo. The isopropylidene ring is in an envelope conformation. The crystal structure is stabilized by means of van der Waals interactions and weak C—H???O interactions.status: publishe

Polymorphism of alprazolam (Xanax®): a review of its crystalline phases and identification, crystallographic characterization and crystal structure of a new polymorphic form

A new polymorphic form of Alprazolam (Xanax®), 8-chloro-1-methyl-6-phenyl-4H-[1,2,4]triazolo-[4,3-][1,4]benzodiazepine, C17H13ClN4, has been investigated by means of X-ray powder diffraction (XRPD), single crystal X-ray diffraction, and differential scanning calorimetry (DSC). This polymorphic form (form III) was obtained during DSC experiments after the exothermic recrystallization of the melt of form I. The crystal unit cell dimensions for form III were determined from diffractometer methods. The monoclinic unit cell found for this polymorph using XRPD after indexing the powder diffractogram was confirmed by the cell parameters obtained from single crystal X-ray diffractometry on a crystal isolated from the DSC pans. The single crystal unit cell parameters are: a = 28.929(9), b = 13.844(8), c = 7.361(3) Å, = 92.82(3)°, V = 2944(2) Å3, Z = 8, space group P21 (No.4), Dx = 1.393 Mg/m3. The structure obtained from single crystal X-ray diffraction was used as initial model for Rietveld refinement on the powder diffraction data of form III. The temperature phase transformations of alprazolam were also studied using high temperature XRPD. A review of the different phases available in the Powder Diffraction File (PDF) database for this drug is described bringing some clarification and corrections.status: publishe

Characterization of ternary solid dispersions of itraconazole, PEG 6000, and HPMC 2910 E5

In order to reduce the crystallinity of PEG 6000, blends were prepared by spray drying and extrusion with the following polymers; PVP K25, PVPVA 64, and HPMC 2910 E5. The maximal reduction of crystallinity in PEG 6000 was obtained by co-spray drying with HPMC 2910 E5. In the next step the model drug Itraconazole was added to the blend and the resulting ternary solid dispersions were characterized. The results of this study show that the addition of PEG 6000 to the Itraconazole/HPMC 2910 E5 system leads to phase separation that in most cases gives rise to recrystallization of either PEG 6000 or Itraconazole. For all ternary dispersions containing 20% of Itraconazole the drug was highly amorphous and the dissolution was improved compared to the binary 20/80 w/w Itraconazole/HPMC 2910 E5 solid dispersion. For all ternary dispersions containing 40% of Itraconazole, the drug was partially crystalline and the dissolution was lower than the dissolution of the binary 40/60 w/w Itraconazole/HPMC 2910 E5 dispersion. These results show that provided Itraconazole is highly amorphous the addition of PEG 6000 to HPMC 2910 E5 leads to an increase in drug release. (c) 2007 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci.status: publishe