Selective analytical determination of cinchocaine hydrochloride in presence of its degradation products or in its binary mixture with hydrocortisone

Cinchocaine HCI was degraded by refluxing with 2N HCI for 4 hr. The degradation products were isolated and their structures were confirmed by IR and mass spectrophotometry. Cinchocaine HCI was then determined in presence of its degradation products by spectrophotometric and spectro-densitometric techniques. For the spectrophotometric methods, cinchocai ne HCI was determined by first derivative spectrophotometry [Dl] at 333.6 nm or by first derivative ratio spectrophotometry [DDI] at 301.6 or 332 nm in concentration ranges 5-80 microg/ml. For the spectro-densitometric method, silica gel plates were used together with benzene: acetone: methanol: 25% NH3 [5:3:0.5:0.1, v/v] as developing solvent and the Rf values were 0.55, 0.12 and zero for cinchocaine HCI and its degradation products, respectively. Cinchocainc HCI and hydrocortisone binary mixture can be determined by the aforementioned densitometric method in concentration ranges 2-20 microg/spot and 2-16 microg/spot for cinchocaine HCI and hydrocortisone, respectively. Alternatively, cinchocaine HCI can be determined spectrophotometrically at 327.8 nm without any interference from hydrocortisone, while hydrocortisone was determined by third derivative spectrophotometry [D3] at 254 and 275.8 nm in concentration ranges 10-100 microg/ml and 5-35 microg/ml for cinchocaine HCI and hydrocortisone, respectively. The proposed methods were successfully applied for the analysis of laboratory prepared mixtures containing cinchocaine HCI and different percentages of its degradation products or cinchocaine HCI and hydrocortisone. These methods were also applied for the analysis of pharmaceutical dosage forms and the results obtained were assessed by the standard addition technique. Local anesthetics produce anesthesia by blocking sodium channels in the axonal membrane, reducing sodium conductance; this in turn reduces the rate and degree of depolarization of the nerve cell and prevents propagation of the action potential.[1] The local anesthetics should be soluble in water and should be effective when injected into tissue or when applied topically to mucous membranesi[2]. Local anesthetics are available as gel, ointments, creams and spray to provide reversible block of conduction along cutaneous nerves[3]. Cinchocaine HCI is a local anesthetic that was formerly used as nerve block and spinal anesthesia, but now, it is available only in topical form[4]. Hydrocortisone is a famous anti-inflammatory agent and it is incorporated with cinchocaine HCI in pharmaceutical preparation for treatment of haemorrhoid[3] Several methods have been described for the determination of cinchocaine HCI. These include spectrophotometric methods [5-15], fluorimetric methods [16-18] HPLC [19-22], TLC [23-27], GC [28-29] NMR [30-31] polarographic methods [32-33] and titrimetric methods [34-37] This work describes spectro-densitometric and spectrophotometric methods for the selective determination of cinchocaine HCI in presence of its two acid degradation products or in combination with hydrocortisone

Spectrofluorimetric determination of bisoprolol fumarate and valsartan in tablets and spiked plasma

Simple, sensitive and rapid spectrofluorimetric procedure is described for the determination of two antihypertensive drugs namely, Bisoprolol fumarate [BSF] and Valsartan [VT]. The effect of solvents was investigated. The fluorescence properties of the two cited drugs showed maximum emission intensity in 0.1N H[2]SO[4] at lambda [em] 298 and 415nm for BSF and VT, respectively, when excited at lambda[ex] 227nm. The calibration graphs were rectilinear from 0.08-1.28 and 0.12-1.6 micro g/ml for BSF and VT respectively. The method, was applied to the determination of the two cited drugs in tablets either single or when co-formulated with hydrochlorothiazide [HZ] with % recoveries of 100.03 +/- 0.57 and 99.70 +/- 0.90 for BSF and VT, respectively. Furthermore, the high sensitivity of the proposed method it allowed its application in spiked human plasma with good % recoveries of 99.73 +/- 2.06 for BSF and 99.94 +/- 1.71 for VT

Spectrophotometric determination of isoniazid nalidixic acid and flumequine through ternary complex-formation with Cd [II] and rose bengal

Simple, sensitive and accurate spectrophotometric procedures for the determination of isoniazid [INH], nalidixic acid [Nx] and flumequine [Fq] are developed. These are based on the reaction of the above mentioned drugs with cadmium [II] to form cationic complexes, which subsequently associate with negatively charged rose bengal to form ion-association ternary complexes. The formed complexes of Nx and Fq are extracted with chloroform, and that of INH with 30% acetone in chloroform to give pink colored solutions with lambda max at 564 nm for Nx and Fq and lambda max at 555 nm for INH. The proposed procedures are applied over concentration ranges of 2.8-5.6 mcg ml-1 of INH, 40-56 mcg ml-1 of Nx and 56-96 mcg ml-1 of Fq. They are successfully applied to the determination of the three drugs in pure and in dosage forms; the relative standard deviations being less than 2%

Spectrophotometric study on the determination of etilefrine hydrochloride in pure from and in some pharmaceutical formulation

A spectrophotometric study on the determination of etilefrine hydrochloride in pure form in some simple pharmaceutical formulations was presented. This study depended upon either direct measurement of the absorbance at 237 nm and at 291 nm, or indirectly by measuring the amplitude height of the first derivative peak at about 245 nm. Both procedures were carried out in alkaline medium of about 0.01 N sodium hydroxide. In compound pharmaceutical formulations containing etilephrine and chlorpheniramine, the direct measurement at 291 nm in alkaline medium is the only successful for the determination of etilefrine. Beer's law is obeyed in the range from 5 to 35 mcg/ml for the direct measurement at 291 nm, and from 5 to 40 mcg/ml for both the direct measurement at 237 nm and for the first derivative technique at about 245 nm

Determination of clorazepate dipotassium via its iodobismuthate complex

A spectrophotometric method and two titrimetric methods for the determination of clorazepate dipotassium via its Iodobismuthate complex are described. These methods depend on, the reaction of clorazepate dipotassium with potassium bismuth iodide which give an orange precipitate. Determination of clorazepate dipotassium in the precipitated complex is done iodometrically using standard potassium iodate solution or complexometrically using standard EDTA solution and xylenol orange indicator. Alternatively, the complex is dissolved in ethyl alcohol and its absorbance is measured at 322 nm. The three methods were successfully applied for the determination of authentic samples of clorazepate dipotassium in the concentration range of 5-25 mg [for the titrimetric method and 40-120 mcg [for the spectrophotometric method]. The mean percentage recoveries were found to be 99.61 +/- 0.81, 99.80 +/- 0.48 - and 99.97 +/- 0.50 for the three methods, respectively. The proposed methods described were successfully applied for the determination of clorazepate dipotassium in tranxene capsules and the validity of the suggested procedures was assessed by applying the standard addition technique

Spectrofluorometric determination of clorazepate dipotassium in presence of its degradation product

A sensitive spectrofluorimetric procedure for the quantitative determination of the intact molecule of clorazepate dipotassium and its degradation product, without separation, was described. The method depends upon the difference of the fluorescence behavior of clorazepate dipotassium and its acidic degradation product; namely, 2-amino, 5-chlorobenzophenone. The concentration of both components are computed from their calculated regression equations. The efficiency of the method has been evaluated by analyzing mixtures of a reference sample of clorazepate dipotassium and controlled, acid-degraded samples; the results obtained are found to concord with both. The method is applied to clorazepate dipotassium bulk powder and to its pharmaceutical formulation, "Tranxene capsules" with an accuracy of 99.7 + 0.58. The proposed procedure is simple, accurate, precise, and less time consuming than the others

Structure of trimethylmethoxysilane and methyl trimethoxysilane

There has been some controversy in the literature concerning the structure 1 of trimethylmethoxysilane, [CH3]3 SiOCH3 [TMS] and of methyltrimethoxysilane, CH3 Si [OCH3]3 [MTS]. Forneris et al. assumed C 3v - geometry for both TMS and MTS and Tanaka performed normal coordinate analysis on MTS assuming also C3v geometry. However, according to [3], the interpretation of the electron diffraction data of MTS seems to speak for C3 geometry of this molecule. During et al. 4 assumed Cs symmetry for the structure of TMS. Two recent studies has presented normal coordinate analysis of TMS. In the present note, Delta v P-R is roughly calculated for both parallel and perpendicular bands of the skeletons of TMS and MTS using C3v geometrical data as a testing procedure to confirm or reject this geometry