Currently, there are no simple one-step methods available to remove ribonucleases (RNases) from solution; however, such is imperative for researchers working with ribonucleic acids (RNAs) because RNases can destroy RNA. We report a simple means to remove RNase from solution. The scheme is based on the encapsulation of a new RNase inhibitor, poly[2'-0-(2,4-dinitrophenyl)]poly-(adenylic acid) (DNP-poly(A)), within porous tetramethoxysilane-(TMOS) or tetraethoxysilane-(TEOS) based solgel-derived silica particles that are used to form a small bioaffinity column. We investigate the activity, binding capacity, and stability of the hybrid DNP-poly(A)/sol-gelderived bioaffinity material. Radioactivity and fluorometric assays are used to determine the response of the solgel entrapped DNP-poly(A) to a variety of RNases. The results clearly demonstrate that DNP-poly(A) entrapped within the sol-gel matrix is active and binds to all RNases tested. There is minimal (< 6%) leaching of the DNP-poly-(A) from the column. The DNP-poly(A)-doped sol-gelderived particles do not require hydrated storage conditions. Biocolumn performance and stability are comparable for DNP-poty(A)-doped TMOS-and TEOS-derived materials. Sodium chloride can be used to regenerated the DNP-poly(A) column. The binding capacity of the biocolumn decreases over time; however, the binding capacity of a 2-month-old DNP-poly(A)-doped biocolumn is several orders of magnitude greater than the typical levels of RNase encountered in contaminated solutions.Bioaffinity or bioselective chromatography is a common means to separate a target analyte specifically and selectively.1-3 In order to prepare a bioaffinity column, one must immobilize a biorecognition element such as an enzyme or an antibody onto the solidphase support material. To prepare such materials, it is common to simply physisorb or covalently bind the biorecognition element to some form of "inert" support.4-6 Unfortunately, while these methods work, the final material is prone to leaching, the
Background: Curcumin and resveratrol are naturally occurring polyphenols that are highly effective in inhibiting the growth of cancer cells. A robust reversed-phase HPLC method has been developed for the simultaneous determination of these two natural drugs. Objective: The method was adapted to analyze both drugs in pure forms, in lipidic nanoemulsion formulation as well as in rat plasma. The method was applied to real samples after intravenous (IV) injection of rats. Method: Analysis utilized C18 column using acetonitrile (ACN)–water (pH adjusted to 4.6 by 1% orthophosphoric acid) in the ratio of 55+45 (v/v) at a flow rate of 0.8 mL/min with detection at 425 and 304 nm for curcumin and resveratrol, respectively. Results: Extraction efficiency of curcumin and resveratrol using ACN–methanol was 96.10–101.00% (RSD 2.49) and 95.00–99.87% (RSD 2.59), respectively. The assay was linear from 0.05 to 4.00 μg/mL (correlation coefficient of 0.9989 and 0.9981, respectively) and precise [average interday and intraday precision for curcumin RSD% (0.45, 2.04) and resveratrol RSD% (2.25, 1.71)] in spiked rat plasma. The LOD and LOQ were found to be (0.0085 μg/mL, 0.025 μg/mL) and (0.02, 0.06), respectively. Conclusions: The data presented demonstrate that the method provides rapid, sensitive, and precise determination of curcumin and resveratrol in spiked rat plasma and in nanoemulsion dosage form without tedious cleanup procedure, which was successfully applied for quantitation of both drugs following their IV administration to albino rats. Highlights: Validated chromatographic method has been developed for simultaneous determination of curcumin and resveratrol. Optimization of chromatographic conditions was achieved. Application of the method on nanoemulsion formula, on spiked rat plasma, and pharmacokinetics study.
Dimethyl sulfate (DMS) and monomethyl sulfate (MMS) are potential genotoxic impurities created during synthesis of some active pharmaceutical ingredients.
Background: Acesulfame-K (ACE), butylated hydroxytoluene (BHT), and aspartame (ASP) are a common combination of food additives added to chewing gums. The abuse of these additives results in severe adverse health effects; however, they are still extensively used owing to their
high performance and low cost. Objective: The development and optimization of a simple, cheap, sensitive, and eco-friendly HPLC/UV method for the simultaneous determination of ASP, ACE, and BHT along with aspartame degradation product phenylalanine (PHEN) in chewing gum. Methods:
The method was optimized using a 5 μm C18 column and an eluent consisting of methanol and 0.1 M phosphate buffer (pH 5.0) according to a suitable gradient elution program. Simple sample preparation, consisting of dilution, homogenization, and sonication followed by centrifugation and filtration,
was optimized and used for the extraction of chewing gum. The greenness of the method was evaluated. Results: The proposed method exhibited excellent linearity (R2 > 0.9996), low LOQ (0.08–0.95 μg/mL), and recoveries between 85.3 and 98.83% with relative
SD (RSD) ≤ 2.7%. High resolution was obtained with <25 min run times with excellent precision (RSD: 0.28–1.33%). This method was successfully applied for the simultaneous determination of ACE, ASP, and BHT in commercial chewing gum; PHEN was not detected. Furthermore, our method
is considered to be environmentally acceptable. Conclusions: The results demonstrate that the developed method can be used to detect ACE, BHT, ASP, and PHEN in chewing gum. Highlights: A new sensitive, green HPLC/UV method is developed to be used as a minimal-cost routine analysis
procedure for commercial chewing gum.
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