Acetous Perchloric Acid Research Articles

Development of non-aqueous titrimetric and spectrophotometric methods for the determination of valganciclovir hydrochloride in bulk drug and tablets

Two non-aqueous titrimetric and one visible spectrophotometric methods were developed and validated for the determination of valganciclovir hydrochloride (VLGH) in pure drug and tablets. The titrimetric methods were carried out by titrating the VLGH solution in glacial acetic acid with acetous perchloric acid (HClO4) in the presence of mercuric acetate and the end point of this titration was being located either visually (method A) or potentiometrically (method B). The spectrophotometric method (method C) was based on the addition of p-dimethylaminobenzaldehyde (DMAB) solution to VLGH solution and the formed yellow condensation product was measured at 420nm. In titrimetric procedures, both the methods A and B were applicable over the range of 4-20mg VLGH, and the calculations were based on a 1:1 reaction stoichiometry (VLGH:HClO4). In a spectrophotometric method, Beer's law was valid in a concentration range of 5-50 μg/mL VLGH with the corresponding value of molar absorptivity of 4.43×103L/mol cm for method C. The limits of detection (LOD) and quantification (LOQ) for method C were 0.3 and 0.92μg/mL, respectively. The developed methods were successfully applied to the determination of VLGH in tablets, and the results were statistically compared with those of a reference method by applying Student's t-test and F-test. Further, the validity of the developed methods was confirmed by recovery studies via standard addition technique.

Non-Aqueous Titrimetric Assay for Determination of Loratadine in Pharmaceutical Preparations

Non-aqueous titrations is the most titrimetric procedure used in pharmacopoeial assays and serves a double purpose, as it suitable for the titration of weak acids and bases and provides a solvent in which organic compounds are soluble. A simple, cost-effective, rapid, and precise method for determination of loratadine (LOR) in pure and pharmaceutical dosage forms was developed. The method based on non-aqueous titration using acetous perchloric acid as a titrant and acetous crystal violet as indicator. All measurements are carried out by running simultaneous blank determinations and the final titer values are subtracted from blank to get actual amount of acetous perchloric acid equivalent to LOR. The method was successfully applied for determination of LOR in pure and some pharmaceutical preparations. The percentage recoveries of the proposed method were ranged from 84.8 ± 0.1% to 100.9 ± 0.1%. The method showed an acceptable precision and accuracy as it able to determine LOR in presence of the different excipients present in some commercial preparations without any significant interference.

Titrimetric assay of isoniazid with perchloric acid in non-aqueous medium

A rapid, simple, cost-effective, accurate and precise direct titrmetric method for the determination of isoniazid (INH) in pharmaceutical preparations has been developed and validated. The method is based on the titration of INH with 0.02 M acetous perchloric acid in glacial acetic acid using crystal violet as indicator. The method is applicable over the range of 1.5–15.0 mg INH. The validation of the method yielded good results that included precision (RSD < 3% for intra- and inter-day precision), and accuracy (relative error ≤2.6%). It was also found that the excipients in the commercial tablet preparation did not interfere with the assay and the results were comparable with the official method.

Non-aqueous titrimetric assay of gabapentin in capsules using perchloric acid as titrant

Two simple, rapid, accurate and inexpensive methods using visual and potentiometric titrimetric techniques are described for the determination of gabapentin (GBP) in bulk drug as well as in capsules. The methods are based on the neutralization reaction of the primary amino group of GBP with acetous perchloric acid as titrant in anhydrous acetic acid medium. The end point was detected either visually using crystal violet as indicator or potentiometrically using modified glass electrode SCE electrode system. Both methods are applicable over the range 1.0-16.0 mg of GBP and the titration reaction follows a 1:1 stoichiometry. The methods were successfully applied to the determination of GBP in capsules. The validity of the proposed methods was further ascertained by parallel determination by a reference method and by recovery studies via standard-addition technique.

Titrimetric and sensitive spectrophotometric methods for the assay of quetiapine fumarate in pharmaceutical formulations

Quetiapine fumarate (QTF) is a selective monoaminergic antagonist with high affinity for the serotonin Type 2 (5HT2), and dopamine type 2 (D2) receptors. Titrimetric and spectrophotometric assay of quetiapine fumarate (QTF) using perchloric acid and acetic acid as reagents are described. The first method (method A) is a non-aqueous titrimetric method and is based on the titration of QTF in glacial acetic acid with 0.01M acetous perchloric acid using crystal violet as indicator. In the second method (method B), QTF has been measured in 0.1M acetic acid spectrophotometrically at a wavelength of 222 nm. The titrimetric method was applicable over the range of 2.0 - 20.0 mg of QTF. The reaction stoichiometry of 1:3 is obtained which served as the basis for calculation. In spectrophotometry, Beer?s law was obeyed over the concentration range of 1.25 - 15.0 ?g mL-1. The linear regression equation of the calibration graph was A = 0.0115 + 0.0673 C with a regression coefficient (r) of 0.9986 (n=7). The apparent molar absorptivity was calculated to be 4.25 ? 104 L mol-1cm-1 and the Sandell sensitivity was 0.0145 ?g cm-2. The limits of detection (LOD) and quantification (LOQ) calculated as per the ICH guidelines were 0.07 and 0.21 ?g mL-1, respectively. Accuracy and precision of the assays were determined by computing the intra-day and inter-day variations at three different levels of QTF. The intra-day and inter-day relative standard deviation (%RSD) were in the range of 0.99 - 2.88 and 1.65 - 2.32%, for method A and method B, respectively, with an acceptable percentage relative error (%RE) &lt; 2%. The methods were successfully applied in the determination of QTF in two different brands of tablets with good accuracy and precision and without detectable interference by excipients. The methods have demonstrated to be simple and easy to apply in routine usage and do not need any costly instrumentation. Therefore, the reported procedures are advantageous and can be adopted in routine quality control laboratories in the developing or under developed countries.

Microtitrimetric determination of a drug content of pharmaceuticals containing olanzapine in non-aqueous medium

Two simple, rapid, reliable and cost-effective methods based on titrimetry in non-aqueous medium are described for the determination of olanzapine in pharmaceuticals. In these methods, the drug dissolved in the glacial acetic acid was titrated with the acetous perchloric acid with visual and potentiometric end point detection, crystal violet being used as the indicator for visual titration. The methods are applicable over 1-15 mg range of olanzapine. The procedures were applied to determine olanzapine in pharmaceutical products and the results were found to be in a good agreement with those obtained by the reference method. Associated pharmaceutical materials did not interfere. The precision results, expressed by inter-day and intra-day relative standard deviation values, were satisfactory, higher than 2%. The accuracy was satisfactory as well. The methods proved to be suitable for the analysis of olanzapine in bulk drug and in tablets. The accuracy and reliability of the methods were further ascertained by recovery studies via a standard addition technique with percent recoveries in the range 97.51-103.7% with a standard deviation of less than 2%.

ChemInform Abstract: Synthesis of 2‐Arylidene Cycloalkane Carboxylates by Lead(IV) Acetate Perchloric Acid Assisted Ring Contraction of 2‐Arylidene Cycloalkanones in Triethyl Orthoformate.

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Synthesis of 2-Arylidene Cycloalkane Carboxylates by Lead(IV) Acetate Perchloric Acid Assisted Ring Contraction of 2-Arylidene Cycloalkanones in Triethyl Orthoformate

Synthesis of 2-Arylidene Cycloalkane Carboxylates by Lead(IV) Acetate Perchloric Acid Assisted Ring Contraction of 2-Arylidene Cycloalkanones in Triethyl Orthoformate

New methods for the determination of aspartame

New titrimetric and spectrophotometric methods are proposed for the determination of aspartame. N-bromosuccinimide (NBS), acetous perchloric acid and sodium methoxide are used as titrants, employing some internal indicators in a titrimetric assay. NBS-metol-sulphanilamide is used for the indirect spectrophotometric determination of aspartame. The charge-transfer complexes formed between aspartame and quinones, namely, chloranilic acid and chloranil, are explored for their spectrophotometric determination. Experimental conditions and recoveries in commercial samples and foods are reported.

Non-Aqueous Titrimetric Determination of Sulphadimidine Sodium and Sulphadiazine Sodium in Injections

Abstract The behaviour of sodium salts of two heterocyclic sulphonamide derivatives (Sulphadimidine and sulphadiazine) in non-aqueous titrimetry was studied. Accordingly a simple and accurate procedure for their determination, based on their titration in acetic anhydride-acetic acid solvent system (5:1) with acetous perchloric acid solution is proposed. Results obtained agreed with those of a pharmacopoeial method.

High-Performance Liquid Chromatographic Determination of Indenolol Hydrochloride and Its Pharmaceutical Formulation

Abstract A high-performance liquid chromatographic assay was developed for the analysis of the beta-adrenergic blocking agent indenolol as a bulk material and in tablet dosage form (Pulsan(R)). Chromatography was done on a reversed-phase system using a Micropak CN-10 column. The mobile phase consisted of 66.7% v/v methanol and 33.3% v/v aqueous acetate buffer of pH 7.0. Detection was performed at the peak maximum of 250 nm utilizing a variable U.V. wavelength detector. Authentic indenolol hydrochloride was employed to establish the calibration curve; and linearity between peak area and concentration proved to be in the concentration range of 2.0 μg/ml to 20 μg/ml. The purity of authentic indenolol hydrochloride powder was checked by non-aqueous potentiometric titration using standard acetous perchloric acid in presence of mercuric acetate.

Diarylmethane formation in the reaction of various metal acetates with alkylbenzenes in the presence of perchloric acid

Treatment of alkylbenzenes with various metal acetates (MnIII, FeIII, CoIII, CuII, and PbIV) in acetic acid containing perchloric acid at reflux temperature affords diarylmethanes as main products: MnIII and FeIII acetates are found to be better reagents than the others, and have comparable activity for diarylmethane formation. Reactions with MnIII acetate–perchloric acid differ from those with FeIII perchlorate (reported previously) in the following ways: the presence of oxygen increases the amount of benzylic aldehyde produced in the former and of diarylmethane produced in the latter reaction; both disproportionation and polymerization, which occur in the latter reaction, are minimized in the former case, making the work-up procedure easier.

Comparison of Analysis of Isoniazid and its Dosge Forms by Several Methods

Four assay procedures for dtrmining soniazid as th powdr and in its dosage forms ae compard. These include iodometric titration, bromometric titration, nitrite titration, and nonaqueous titration with acetous perchloric acid. The presence of reducing sugars nterferd with the iodomeric titration. The fou methods do not distinguish isoniazid and its hydraone derivative. However, he presence of hydraone may be a serious poblem since i may interfe wih the bioavilability of isoniazid. Ferocyphen was found suitable as an inernal indicaor in th nitrie titration method.

Differential Nonaqueous Titration of Isoniazid and Sodium p-Aminosalicylate Mixtures

Isoniazid and sodium p-aminosalicylate are estimated potentiometrically in nonaqueous media. Their mixtures are amenable to differential nonaqueous titrimetry. The titration solvent consists of a mixture of equal volumes of acetonitrile and acetic anhydride, the titrant is acetous perchloric acid, and electrode system is the glass-calomel electrode pair. Satisfactory resolution of end points is obtained with the ratio of sodium p-aminosalicy-late-to-isoniazid as high as 4:1. Both of these components in mixtures can be determined in a single titration by the proposed method without resorting to preliminary separation.

Nonaqueous Titration of Theophylline Combinations with Acetous Perchloric Acid

Synthetic mixtures of theophylline and sodium acetate, salicylate, and glycinate are titrated with acetous perchloric acid using a potentiometer for the detection of the end points. Differentiation of the equimolecular mixtures could be realized in the solvent mixture containing benzene-acetic anhydride-acetic acid (18:4:1). The method is applied to assay theophylline combinations and their tablets. The results are compared to those obtained by official methods. Synthetic mixtures of theophylline and sodium acetate, salicylate, and glycinate are titrated with acetous perchloric acid using a potentiometer for the detection of the end points. Differentiation of the equimolecular mixtures could be realized in the solvent mixture containing benzene-acetic anhydride-acetic acid (18:4:1). The method is applied to assay theophylline combinations and their tablets. The results are compared to those obtained by official methods.

Steroids. Part XXXI. Attempted modification of the 14α-methyl group in 4,4,14α-trimethyl steroids

5α-Lanost-8-en-3β-yl acetate was converted by way of 3β-acetoxy-5α-lanost-8-en-7-one into 3β-acetoxy-7α-hydroxy-5α-lanost-8-ene, which as the 7α-nitrite did not undergo the Barton reaction, and which with lead tetra-acetate–iodine gave 3β-acetoxy-5α-lanosta-7,9(11)-diene. 3β-Acetoxy-5α-lanost-9(11)-en-7-one, when hydrogenated over platinum in ethyl acetate–perchloric acid gave only 3β-acetoxy-5α-lanosta-7,9(11)-diene, whilst use of sodium borohydride yielded mainly 3β-acetoxy-7β-hydroxy-5α-lanost-9(11)-ene. Reductive cleavage of the 7β,8β-epoxide of 3β-acetoxy-5α-lanosta-7,9(11)-diene also yielded a 7β-hydroxy-5α-lanost-9(11)-ene; the 7α,8α-epoxide of 3β-acetoxy-5α-lanosta-7,9(11)-diene could not be prepared.

Determination of Some Mercurials via Acetolysis and Nonaqueous Acidimetric Titration

An analytical method for certain mercurials is based upon their solvolysis in acetic acid to yield either mercuric acetate or a monosubstituted mercuric acetate. When an excess of methylamine hydrochloride is added, an amount of strong base is released which is equivalent to the mercury-bound acetate. The solution is titrated with standard acetous perchloric acid to complete the analysis. The method is applicable to many mercurials containing a mercury-nitrogen, mercury-oxygen, or mercury-sulfur bond.

Determination of Piperazine in Formulations by Nonaqueous Titration

Abstract A new method is presented for the nonaqueous titration of piperazine in formulations in which the piperazine base is first brought into aqueous solution, and the solution is made strongly alkaline and extracted with chloroform. The chloroform solution of piperazine is then titrated with acetous perchloric acid to alpha-naphthol benzein indicator. The procedure is rapid, shows good agreement with other methods, and is applicable to most kinds of piperazine formulations. An alternative procedure for piperazine adipate, citrate, or tartrate in powders is given, in which the compound is dissolved and titrated directly in glacial acetic acid.

The assay of sodium citrate and sodium potassium tartrate by cation exchange and non-aqueous titrimetry

Sodium citrate and sodium potassium tartrate are assayed by passing aqueous solutions of the salts through cation exchange resin columns, concentrating the effluents from the columns, and then titrating the effluents with standard sodium hydroxide solution. Sodium citrate is assayed by titrating a solution of the salt in glacial acetic acid with standard acetous perchloric acid, the end-point being detected potentiometrically; sodium potassium tartrate is assayed by stirring the salt in excess standard acetous perchloric acid, and then backtitrating the excess acetous perchloric acid with standard acetous potassium acetate, the end-point being detected potentiometrically.

A Study of the Titration of Organic bases in chlorobenzene with acetous perchloric acid

Potentiometric titrations can be carried out in chlorobenzene by using glass and sleeve-type calomel electrodes and a Beckman Model GS pH Meter. Acetous perchloric acid is the most suitable titrant. Galvanometer response is rapid and no erratic galvanometer needle deflections are noted when this titrant is used. The optimum concentration of titrant at the end point appears to be approximately 20 parts titrant for every 100 parts of solution. Bases as weak as caffeine can be determined in this solvent but only with a limited degree of accuracy. A mixed solvent containing 20 per cent glacial acetic acid in chlorobenzene can be used for the duration of organic bases insoluble in chlorobenzene. Bromophenol blue is a suitable indicator for use in chlorobenzene. Neutral red, brilliant green, and methyl red can also be used in this solvent but indicator changes are not as satisfactory as with bromophenol blue.