Dosage analysis

Development of protocols for assay and stability determinations of chemical/vehicle mixes and dosage analysis. 

Liquid Dosage Forms. Simple aqueous solutions, symps, elixirs, and tinctures are prepared by dissolution of solutes in the appropriate solvent systems. Adjunct formulation ingredients include certified dyes, flavors, sweeteners, and antimicrobial preservatives. These solutions are filtered under pressure, often using selected filtering aid materials. The products are stored in large tanks, ready for filling into containers. QuaUty control analysis is then performed. 

Cromakalim (137) is a potassium channel activator commonly used as an antihypertensive agent (107). The rationale for the design of cromakalim is based on P-blockers such as propranolol (115) and atenolol (123). Conformational restriction of the propanolamine side chain as observed in the cromakalim chroman nucleus provides compounds with desired antihypertensive activity free of the side effects commonly associated with P-blockers. Enantiomerically pure cromakalim is produced by resolution of the diastereomeric (T)-a-meth5lben2ylcarbamate derivatives. X-ray crystallographic analysis of this diastereomer provides the absolute stereochemistry of cromakalim. Biological activity resides primarily in the (—)-(33, 4R)-enantiomer [94535-50-9] (137) (108). In spontaneously hypertensive rats, the (—)-(33, 4R)-enantiomer, at dosages of 0.3 mg/kg, lowers the systoHc pressure 47%, whereas the (+)-(3R,43)-enantiomer only decreases the systoHc pressure by 14% at a dose of 3.0 mg/kg. 

Torque Rating The choice of torque rating has been discussed earlier. Torque is a function of such factors as quantity and quality of underflow (therefore, of such parameters as particle characteristics and flocculant dosage that affect underflow character), unit area, and rake speed but, in the final analysis, torque must be specified on the basis of experience modified by these factors. Unless one is experienced in a given apphcation, it is wise to consult a thickener or clarifier manufacturer. 

To obtain a meaningful isotherm, as wide a range of carbon dosages as practical should be used. Recommended dosages are 0.05, 0.1, 0.2, 0.5, 1.0, 2.5, 5.0, and 10.0 g of carbon per 100 g of the test liquid. Prior to analysis of the treated liquid, the carbon must be removed from the liquid. Carbon can be removed by filtration. The filtration rate may be increased by using heat or pressure. If the liquid is so viscous that filtration is difficult, centrifugation can sometimes be used as a suitable separation. 

Several randomized trials have demonstrated that leuprolide and goserelin are effective agents when used alone in patients with advanced prostate cancer.19 Response rates around 80% have been reported, with a lower incidence of adverse effects compared with estrogens.19 There are no direct comparative trials of the currently available LHRH agonists or the dosage formulations, but a recent meta-analysis reported that there is no difference in efficacy or toxicity between leuprolide and goserelin. Therefore, the choice between the two usually is made based on cost and patient and physician preference for a dosing schedule. 

In the clinical area, the largest share of analytical methods development and publication has centered on the determination of theophylline in various body fluids, since theophylline is used as a bronchodilator in asthma. Monitoring serum theophylline levels is much more helpful than monitoring dosage levels.44 Interest in the assay of other methylxanthines and their metabolites has been on the increase, as evidenced by the citations in the literature with a focus on the analysis of various xanthines and methylxanthines. 

WJ Westlake. The design and analysis of comparative blood-level trails In J Swarbrick, ed. Current Concepts in the Pharmaceutical Sciences Dosage Form Design and Bioavailability. Philadelphia, PA Lea Febiger, 1973. 

As the list of applications illustrates, the techniques of optimization are not limited to tablets or even to solids. Any dosage form and any process should be amenable to this type of experimentation and analysis. From the most simple formulation to the most complicated one, there are ingredient levels and processing steps that can be varied, and any information on the result of such variation should be useful to the formulator. 

As can be seen from Table 28.7, the required dosage of NaOH does not increase significantly when the limb dosage is more than 20g/1000mL. The mixed wastewater, which was treated with the dosages of lime and NaOH shown in Table 28.7, was then aerated for 15 min after the pH reached 8.5. After aeration, it was allowed to settle for a period of 30-120min. An analysis of the clear phase after settling is shown in Table 28.8.3 The wastewater was treated with 15 g/L of lime... 

Below 200°C, reliable urea thermohydrolysis is very hard to achieve, therefore urea dosage is usually stopped in real-world urea-SCR systems in this temperature regime. Another serious problem connected with the urea injection at low temperatures is the formation of white to yellowish deposits, which are observed when urea solution is injected at very low exhaust gas temperatures or if the urea spray forms a thick film at the walls of the SCR system. The analysis of these deposits [26] showed that they mainly consist of urea and some biuret at low temperatures and of cyanuric acid and some biuret at higher exhaust gas temperatures around 350°C. From laboratory investigations of the urea decomposition, it is known that biuret is easily formed from 150 to 190°C [27], whereas the formation of cyanuric acid is predominant from 200 to 300°C, according to the following reactions [12] ... 

Under contract to the Systems and Strategy Development Division of the OAQPS/EPA, Systems Applications developed and applied modeling methods for the estimation of human exposure and dosage from airborne materials. The model is intended for a screening analysis of the impacts of chemicals under EPA review as potentially hazardous by the definitions of the NESHAPS program. 

Cavrini et al. [32] reported the development of a colorimetric method for the determination of miconazole nitrate in pharmaceutical preparation. The method is based on the formation of a yellow complex between the drug and bromocresol green. The absorption peak of this complex, extracted by chloroform over the pH 2—4 range, was at 424 nm, and linear response was obtained from 3—13 pg/mL. The molar absorptivity of the complex in chloroform was 1.845 x 104. This procedure is suitable for the analysis of miconazole nitrate in commercial dosage forms. 

A specific and sensitive fluorimetric method was proposed by Al-Majed for the determination of (7))-penicillamine in its pure state and in its dosage forms [24], The method is based on the coupling between (/))-penicillamine and 4-fluoro-7-nitroben-zo-2-oxa-1,3-diazole, and analysis of the fluorescent product was measured at an excitation wavelength of 465 nm and an emission wavelength of 530 nm. The fluorescence intensity was found to be a linear function of the drug concentration over the range of 0.6-3 pg/mL, and the detection limit was 2 ng/mL (13 nM). 

Abou-Ouf et al. [16] described a spectrophotometric method for the determination of primaquine phosphate in pharmaceutical preparation. Two color reactions for the analysis of primaquine phosphate dosage form, which are based on 2,6-dichlor-oquinone chlorimide and l,2-naphthoquinone-4-sulfonate, were described. The reactions depend on the presence of active centers in the primaquine molecule. These are the hydrogen atoms at position 5 of the quinoline nucleus and the primary amino group of the side chain. The method was applied to tablets of primaquine phosphate and a combination of primaquine phosphate and amodiaquine hydrochloride. 

Sidhu et al [86] developed a reliable and simple high performance liquid chromatographic method for the routine analysis of pharmaceutical dosage forms using a Cig Bondapak reversed-phase column with a binary solvent system consisting of... 

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