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

Spectrophotometric determination of mianserin and risperidone

Simple and sensitive spectrophotometric methods were described for the determination of two drugs; namely, mianserin and risperidone, with n-donating groups. The methods were based mainly on charge transfer complexation reactions, with two acceptors 2,3-dichloro-5,6-dicyano benzoquinone [DDQ] and p-chloranilic acid [p-CA], and ion pair complexation reactions with some acidic dyes, namely, bromophenol blue [BPB], bromothymol blue [BTP] and bromocresol green [BCG]. In the first procedure the drugs were treated with DDQ or p-CA in acetonitrile, the colored products were quantified spectrophotometrically at 587 nm and 520 nm for mianserin and 457 nm and 520 nm for risperidone using DDQ and p-chloranilic acid, respectively. In the second procedure drugs were treated with acidic dyes in chloroform, the complexes formed are measured at 411 nm, 411 nm and 414 nm in case of mianserin and 415 nm, 415 nm and 419 nm for risperidone with BPB, BTB and BCG, respectively. The effect of several variables affecting color development was studied and the molar ratio of reactants was established in each case. Linearity ranges were found to be 12-55 mug ml-1, 40-200 mug ml-1, 2-10 mug ml-1, 2.5-12 mug ml-1 and 3-12 mug ml-1 for mianserin and 25-135 mug ml-1, 40-220 mug ml-1, 3.5-15 mug ml-1, 4-18 mug ml-1 and 4-18 mug ml-1 for risperidone using DDQ, p-chloranilic acid, BPB, BTB and BCG, respectively. The proposed methods were applied successfully for the analysis of both drugs in raw material and in pharmaceutical dosage forms with good accuracy and precision. The results were compared statistically with reference methods commonly used for the determination of the drugs

Simultaneous determination of hydrochlorothiazide in combination with amiloride HCI or with spironolactone

Spectrophotometric and spectro-densitometric methods were used for the analysis of mixtures of hydrochlorothiazide with amiloride HCl or with spironolatone. In the spectrophotometric methods, the zero crossing of the second derivative spectrum was used for the determination of hydrochlorothiazide and amiloride HCl mixture at 252 nm and 387 nm, respectively, while, derivative ratio method was used for determination of hydrochlorothiazide and spironolactone mixture at [269 nm and 280 nm] and [237 nm and 246 nm], respectively. The proposed densitometric and spectrophotometric methods were applied to the analysis of laboratory prepared mixtures and pharmaceutical dosages forms containing hydrochlorothiazide with amiloride HCl or with spironolactone, and satisfactory results were obtained

Determination of papaverine hydrochloride through its reaction with iodine

The formation of charge transfer complex by the reaction of papaverine base with iodine in chloroform was studied. The complex showed maximum at about 285 nm suitable for quantitative determination of the concentration 8 - 22 ug/ml. Alkaloidal salts form precipitate when treated with Wagners reagent [iodine/potassium iodide]. Stoichiometric study of the precipitate of papaverine hydrochloride with iodine indicated that, it is formed in the ratio of 1:6, respectively. Solution of the formed precipitate in chloroform absorbs maximally at about 290 nm. Concentrations adhering to Beer's Law are 4-14 mg/100 ml. The proposed methods are specific, accurate and precise as compared with the official non-aqueous titration procedure

Determination of papaverine hydrochloride through its reaction with N.B.S.

Papaverine hydrochloride is allowed to stand with N-bromosuccinimide [NBS] in acid medium for 30 minutes, where an orange color develops, that absorbs maximally at 391 nm. This method is sensitive over concentration 1-6 mg/100 ml. The reaction of papaverine hydrochloride with NBS was further investigated quantitatively. Direct titration of papaverine hydrochloride with NBS was not successful. However, quantitative determination of papaverine hydrochloride was possible under the condition of back titration. It is suggested that papaverine hydrochloride is broken down into smaller fragments associated with the production of orange color. The methods were applied to the analysis of laboratory prepared mixtures, as well as to pharmaceutical preparations

Simultaneous determination of papaverine hydrochloride/anlagen mixture in presence of homatropine methyl bromide in pharmaceutical preparations

In this work, a simple first-derivative [D1] method for the simultaneous analysis of papaverine hydrochloride/analgin [dipyrone] mixture in the presence of homatropine methyl bromide, was described. D1 spectrum of papaverine hydrochloride exhibits at 257 nm a definite peak where analgin and homatropine methyl bromide reads a zero [D1] value. Similarly, analgin exhibits a definite peak at 287 nm without interference from papaverine hydrochloride and homatropine methyl bromide. The method was applied successfully to the analysis of supergine ampoules. The mean percentage recoveries +/- SD were found to be 100.66 +/- 0.43, 100.64 +/- 0.87 for papaverine hydrochloride and analgin, respectively. Analgin was determined iodimetrically followed by spectrophotometric measurement of papaverine hydrochloride in the solution. Oxidation of analgin resulted in a blue shift in its spectrum, this permits direct spectrophotometric determination of papaverine hydrochloride without any interference. The method was applied to the analysis of supergine ampoules. The mean percentage recoveries +/- SD were found to be 100.10 +/- 0.67 and 99.49 +/- 1.71 for papaverine hydrochloride and analgin, respectively. On applying both of the proposed methods the results obtained were verified by the standard addition technique, where good percentage mean recoveries with relatively low deviations were obtained

Simultaneous spectrophotometric determination of papaverine hydrochloride in presence of dyphylline in pharmaceutical preparations

The absorbance of papaverine hydrochloride at 310 nm. was utilized for its direct spectrophotometric determination. The mean percentage recoveries +/- S.D. were found to be 100.16 +/- 0.84 and 100.31 +/- 0.93 in laboratory prepared mixture and sedocardine tablets respectively. Diphylline has been determined in presence of paraverine by derivative spectrophotometry at 287 nm. The mean percentage recoveries +/- S.D. were found to be 100.14 +/- 0.73 and 100.25 +/- 0.44 in sedocardine tablets and laboratory prepared mixture respectively. Moreover, the problem of overlapped peaks in the Ultra-violet spectra of papaverine hydrochloride-diphylline mixture was solved using Vierordt's equation. Both compounds can be determined simultaneously by measuring at 250, 273 nm. In order to obtain accurate results paraverine hydrochloride/diphylline ratio should be in the order of 1:3-1:5 respectively. The method was applied to sedocardine tablets, the validity of the method was ascertained by the standard addition technique. The mean percentage recoveries +/- S.D. were found to be 100.07 +/- 1.19 and 100.06 +/- 0.58 for papaverine hydrochloride and diphylline respectively. The results obtained by adopting the proposed methods showed good percentage mean recoveries and were statistically valid