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Phycochemical screening and standard parameter determination of Spirulina plantesis, Chlorella vulgaris, and Euchema spinosum, cultivated in Indonesia
Published in Ade Gafar Abdullah, Isma Widiaty, Cep Ubad Abdullah, Medical Technology and Environmental Health, 2020
I.T. Maulana, L. Mulqie, K.M. Yuliawati, Y. Sukarman, N.A. Suhara, N.A. Suhara, R. Safira
Determining the water content in the material was done by three methods, namely Karl Fischer titration, azeotropic distillation, and gravimetry. The gravimetric method was done by measuring the amount of compound that evaporates/disappeared after the material was heated within a certain period. Water content could be determined by the gravimetric method if it was certain that there were no other metabolite compounds that could evaporate at 105ºC beside water, such as essential oils and other compounds (Menkes 2009). If there were volatile compounds in the material, then the amount of water content could not be determined by the gravimetric methods but by the azeotropic distillation method.
Measurement Techniques
Published in Marvin C. Ziskin, Peter A. Lewin, Ultrasonic Exposimetry, 2020
Marvin C. Ziskin, Peter A. Lewin
The acoustic radiation force is the time-average force exerted by an acoustic field on an object. The acoustic radiation force may often be of relevance in ultrasonic fields in various circumstances, in biological tissues, and elsewhere. The type of instrument used to accomplish the task is generally referred to as the radiation force balance, although gravimetric balances in the strict sense constitute only one group of the devices. The irrelevance of the additional constant is often referred to as the so-called Langevin condition in the literature and generally attributed to the open-vessel situation typical of usual radiation force measurements. There is a large variety of radiation force devices with which various force-measuring methods are applied. The suspension wire(s) penetrating the water surface may lead to disturbing buoyancy and surface tension forces. The radiation force is obtained by extrapolating the signal back to the moment of switching the transducer.
Physico-Chemical Methods for the Quality Control of Medicinal Plants, Plant Derivatives and Phytomedicines in Brazil
Published in Luzia Valentina Modolo, Mary Ann Foglio, Brazilian Medicinal Plants, 2019
Paula Carolina Pires Bueno, Alberto José Cavalheiro
The determination of the solubility of a dry extract in any given solvent and temperature constitutes another characterization test. This information is important both to assess the quality of the received batch and as a parameter in formulation studies. The analytical procedure is simple and consists adding increasing portions of the sample to constant volumes of solvent in which the extract must be analyzed. The total amount of solute is determined in the supernatant liquid. Results are calculated by gravimetry and usually expressed in mg/g.
Assessing variability of aerosols generated from e-Cigarettes
Published in Inhalation Toxicology, 2022
Darpan Das, Sarah-Marie Alam El Din, Jairus Pulczinski, Jana N. Mihalic, Rui Chen, Joseph Bressler, Ana M. Rule, Gurumurthy Ramachandran
Thus, aerosol dynamics make evaluation between studies done by different investigators using different devices hard to compare. It has been reported that puffing protocol (i.e. duration, frequency and volume), dilution air, and length of time measurement are important parameters that influence the particle dynamics of aerosols generated from e-cigarettes (Ingebrethsen et al. 2012; Mikheev et al. 2016, 2018). Similar observations were also reported by Ruprecht et al. 2014, where they found that nicotine-enriched e-cigarettes produced lower PM levels than similar nicotine-free e-cigarettes. Ruprecht et al. 2014 attributed this phenomenon to the change in the optical properties of the PM such as color, morphology and other physical and chemical parameters. Furthermore, the argument is not limited to optical instruments and may also be applicable to gravimetric measurements. The filter substrate media is not able to capture the semi-volatile aerosols that are present in the environment. Further, adding flavors increases the vapor pressure and thus increases the volatility. Hygroscopicity and volatility of aerosols generated from e-cigs contribute to large extent toward the variability (Ingebrethsen et al. 2012). PG:VG is the main constituent in the e-liquid as well as in aerosol droplet formed in the vaping process (Gillman et al. 2020). Aerosols are generated both in the particle phase as well as the vapor phase (Pankow et al. 2018). For the scope of the present study, aerosols were only measured for the particle phase.
Preparation and evaluation of oral self-microemulsifying drug delivery system of Chlorophyll
Published in Drug Development and Industrial Pharmacy, 2021
Ling Lin, Sajid Asghar, Lin Huang, Ziyi Hu, Qineng Ping, Zhipeng Chen, Feng Shao, Yanyu Xiao
In the intestinal absorption experiment, the intestine also absorbs water to a certain extent that changes the concentration of the perfusate. The measured results might not reflect the true absorption status, so corrections are needed. At present, the most commonly used method is to add markers (such as: phenol red, 14C-PEG) [48] for calibration. However, markers such as phenol red will interfere with the assay of certain drugs. In the long-term experiment, phenol red might also get partially absorbed. Although 14C is not absorbed, the detection is tedious and the safety is poor. According to comparative studies, the gravimetric method can significantly improve the accuracy of experimental data and significantly reduce the experimental error than the phenol red method. Therefore, in this study, we used the weight correction method to correct the absorption of water [49].
Investigational topical anticholinergics in clinical development for the treatment of hyperhidrosis
Published in Expert Opinion on Investigational Drugs, 2021
Stamatios Gregoriou, Anna Campanati, Dimitrios Rigopoulos, Anna Maria Offidani, Alexandros Stratigos, George Kontochristoulos
SB is an ester analog of glycopyrrolate. SB follows the principles of retrometabolic drug design. A recent multicentric, double blind, placebo-controlled phase II trial compared three concentrations of 5%, 10%, 15% of SB gel applied once daily for 42 days in 227 patients with AH. A significantly higher percentage of participants in each SB group exhibited ≥1 and ≥2 points improvement in the Hyperhidrosis Disease Severity Measure-Axillary score (HDSM-Ax) vs the vehicle group. Gravimetry and HDSS also showed statistically significant improvement. Adverse events resulted in 12 participants discontinuing, the study and included dry eyes, dry mouth, blurred vision, mydriasis, urinary retention, constipation, as well as topical erythema, burning or itching sensation and dryness at the application site [12]. A Phase III with the 5% gel in 281 Japanese patients resulted in approval in Japan. Patients who achieved both HDSS of 1 or 2 and a 50% reduction in gravimetric weight of sweat at the end of 6 weeks were 44.0% in the SB group and 30.7% in the vehicle group. SB is contraindicated in patients with angle-closure glaucoma and in those with dysuria due to benign prostatic hyperplasia [13].