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Drug Substance and Excipient Characterization
Published in Dilip M. Parikh, Handbook of Pharmaceutical Granulation Technology, 2021
Parind M. Desai, Lai Wah Chan, Paul Wan Sia Heng
A calibrated pycnometer is used to determine the true volume of the test sample. The true density is obtained by dividing the mass of the sample by its true volume. Samples used for true density measurements should be very dry as the vapor pressure of volatiles at low pressure can introduce measurement errors [42,43].
Glycerine Analysis
Published in Eric Jungermann, Norman O.V. Sonntag, Glycerine, 2018
Several styles of pycnometer are in use, and are quite satisfactory if they are calibrated carefully and used with a water bath capable of good temperature control. One such pyenometer is pictured in Figure 7.3. The bottle is filled completely with glycerine at room temperature, being careful to avoid air bubbles. It is then equilibrated in a constant-temperature bath at 25°C + 0.1°C, with the sidearm cap removed. This permits glycerine to expand out of the bottle as it warms. The bottle is removed from the bath, and the sidearm cap is placed on the bottle. The outside of the bottle is dried carefully and the bottle is weighed. The weight is compared with the weight of water prepared the same way. AOCS method Ea 7–50 reports that duplicate determinations made in two different laboratories should be within 0.00025 units of each other.
Solid State Testing of Inhaled Formulations
Published in Anthony J. Hickey, Sandro R.P. da Rocha, Pharmaceutical Inhalation Aerosol Technology, 2019
Philip Chi Lip Kwok, Hak-Kim Chan
Density equals mass divided by volume. However, there are several types of densities with regards to solids, depending on what volume is included in the measurement. True density of a compound is the mass divided by the volume of the atomic or molecular unit cell in a crystal, without voids. It can be derived from X-ray diffraction data on the composition and volume of a unit cell (British Pharmacopoeia 2017, European Pharmacopoeia 2017). Pycnometric density is obtained by measuring the volume occupied by a powder in a gas displacement pycnometer (British Pharmacopoeia 2017, European Pharmacopoeia 2017, United States Pharmacopeia 40-National Formulary 35 2017). There are two chambers in the gas pycnometer, namely, a calibrated test chamber with volume Vc and an expansion chamber with volume Vr. They are connected by a valve in between. A known mass of powder is first put into the test chamber. After closing the pycnometer and with the valve open between the two chambers, the reference pressure (Pr) is recorded. That valve is then closed and the test chamber is filled with a gas to an initial pressure Pi. Helium is usually used because it can fill small pores due to its high diffusivity. Then the valve between the two chambers is opened and the final pressure within the two connected chambers becomes Pf. The volume occupied by the sample (Vsample) can be calculated as below (British Pharmacopoeia 2017, European Pharmacopoeia 2017, United States Pharmacopeia 40-National Formulary 35 2017):
Mechanics of tablet formation: a comparative evaluation of percolation theory with classical concepts
Published in Pharmaceutical Development and Technology, 2019
Saurabh M. Mishra, Bhagwan D. Rohera
True density of the powder materials was determined using a gas pycnometer (AccuPyc® II 1340, Micromeritics Instruments Corp., Norcross, GA). The pycnometer allows nondestructive measurement of volume and density of powder and solid materials, and uses a gas displacement technique to determine the volume of the sample under test. An inert gas (helium) was used as the displacement medium. Pycnometer was calibrated with an iron sphere of known mass prior to each measurement. For the determination, a known weight of powder sample was transferred into an aluminum sample container of 3.5 cm3 volume, and helium gas was passed through the sample from the reservoir. The determinations were carried out at room temperature. The instrument automatically purges moisture and volatile materials from the powder sample and repeats the analysis until successive measurements yield consistent results. The determination of sample density was repeated for up to 10 cycles. The average reading of 10 cycles was recorded as the true density of the material.
Effect of Rose Syrup and Marigold Powder on the Physicochemical, Phytochemical, Sensorial and Storage Properties of Nutricereals and Milk-Based Functional Beverage
Published in Journal of the American College of Nutrition, 2021
Ashwani Kumar, Amarjeet Kaur, Vidisha Tomer, Kritika Gupta, Kamaljit Kaur
Total soluble solids (TSS) were measured using a hand-held refractometer. To measure total solids the moisture was evaporated from a weighed sample at a temperature of 70 °C and the weight of dried residue was noted. The pH was measured using Oakton digital pH meter, USA, after calibration. Titratable acidity and ash content were determined as per the method described by Ranganna (25). Water activity was measured by a portable water activity meter (Decagon devices, USA). Density was measured with the help of pycnometer (26). To measure viscosity a Brookfield viscometer, fitted with ultra-low adapter spindle was used. The temperature of the sample during measurement was kept constant at 20 °C and the speed of spindle was 20 RPM. Starting from 30 to 180 seconds, six observations with a time interval of 30 seconds were taken. The final viscosity was represented as the average of six values. Dietary fiber and β-glucan were measured using total dietary fiber and β-glucan kit (Megazyme, Bray, Ireland). Cholesterol estimation involved four major steps i.e. extraction, saponification, derivatization and analysis. The sample was extracted with hexane, followed by saponification with KOH, re-extraction with toluene and derivatization with hexamethyl disilane and trimethyl chlorosilane. This was further mixed vigorously and centrifuged. The upper layer was collected and injected to gas chromatograph (Varian 3800 cP, Palo Alto, California) fitted with flame ionization detector. During the analysis, the detector was maintained at a temperature of 300 °C and the flow of nitrogen, hydrogen and zero air were maintained 29 ml/min, 30 ml/min and 300 ml/min, respectively. The cholesterol concentration in the sample was determined by comparison with a standard curve of the cholesterol standard solutions (3,27).
Ethanol content in traditionally fermented ayurvedic formulations: Compromised Good Manufacturing Practice regulations – compromised health
Published in The American Journal of Drug and Alcohol Abuse, 2019
Mukesh Maithani, Harpreet Grover, Richa Raturi, Vikas Gupta, Parveen Bansal
The literature reveals that numerous analytical methods based on gas chromatography, UV spectrophotometry, and density measurements of distillates by pycnometer or aerometer have been reported for the determination of ethanol in ayurvedic formulations. The most popular method based on the density measurements of distillates by pycnometer or aerometer (44–48) has been recommended by the European Pharmacopoeia (49). Pycnometer or aerometer methods have many disadvantages like low sensitivity, less accuracy, less specificity, and nonapplicability for actual samples like syrup formulations because of the lengthy and difficult sample preparation as compared to GC method developed in present study. At the same time, GC method is more accurate, precise, reproducible, and sensitive as compared to UV method due to smaller injection volume, simplicity, and wider applicability (1,50,51). Few GC methods have also been reported for estimation of ethanol content (52–57). The method is simple because the mode of separation is isothermal in the present method as compared to gradient mode in traditional method. In present method, even the quality of ethanol peak generated is sharp, well defined with clear baseline and minimized errors that normally creep in quantitative analysis as compared to reported method which shows tailing (52). Furthermore, the traditionally used GC methods require time-consuming complex sample pretreatment procedures involving solid-phase extraction, solvent extraction, and distillation to improve the volatility and avoid column interactions (53–56), whereas in present study, a simple, user-friendly, and rapid method without any sample pretreatment procedure has been developed. In newly developed method, the sample pretreatment procedure has been avoided as the samples were mixed with diluent and are ready to be injected into a GC for determination of ethanol content. The developed method is less time-consuming as it excludes the incubation time, injection time, pressurize time, and withdrawal time. The method is economic as it saves manpower and instrument working hours, thus giving a long life to costly GC equipment and columns as compared to conventional headspace method (57).