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PubMed1993

Near-infrared spectroscopy as an alternative to assess compliance of ampicillin trihydrate with compendial specifications.

The suitability of near-infrared spectroscopy (NIRs) as an alternative to several compendial test methods such as identification, water content and assay, in the release procedure of drug substances is demonstrated with ampicillin trihydrate as an example. It is also shown that in cases in which a manufacturing process is well under control, a 'standard activity' can be assigned to a batch when its conformity with 'standard quality' is proven by means of its NIR spectrum. For that purpose a new quality parameter--the Conformity Index (CI)--is introduced.

Ampicillin↗
PubMed1994

Chromatographic analysis of selected tetracyclines from dosage forms and bulk drug substance using polymeric columns with acidic mobile phases.

The LC analysis of selected tetracyclines from dosage forms and bulk drug substance using polymeric columns has been studied. Mobile phases containing acetonitrile-0.02 M sodium perchlorate (pH 2.0) were used. The tetracyclines were detected by their absorbance at 280 nm. The columns included: a polystyrene-divinylbenzene (PS-DVB) column and a polymethacrylate column with octadecyl ligands (PM-C18). Performance of the two columns was compared and applicability of the described methods for compendial use has been evaluated. The tetracyclines investigated include: minocycline, oxytetracycline, tetracycline, demeclocycline, chlortetracycline, methacycline, doxycycline and meclocycline.

Acetonitriles↗
PubMedDate not supplied

Eliminating interferences in a compendial test for oxidizable substances in water.

The United States Pharmacopoeia (USP) uses acidified potassium permanganate to test for dissolved organics in pharmaceutical-grade water. In the test, a standard permanganate concentration is added to a boiling, acidified water sample. Visually inspecting the sample for residual permanganate determines whether the sample passes (pink color remains) or fails (pink color disappears) the test. The permanganate redox chemistry is complex, however, and test samples are prone to developing suspended particulate and colors other than pink. Forming hazy or off-colored solutions interferes with the subjective end point determination according to the USP test. We report two alternative end point determinations that essentially eliminate interferences from the compendial test method. The first alternative involves recording a uv-visible spectrum of the reduced permanganate test solution. Residual permanganate shows three distinct absorbance maxima at 510, 526, and 545 nm. It is straightforward to differentiate the characteristic permanganate fingerprint from the broad, lower-wavelength extinction that results from interfering substances. The second alternative involves filtering the reduced permanganate test solution through sintered glass. This filtration step removes manganese oxides and other colloidal particles that contribute to haze and off color formation in test samples. Visually inspecting the filtrate for residual pink color remains the end point determination for the test method. A third alternative method, namely spectrophotometric determination of permanganate loss rate constants is not a suitable alternative owing to a strong dependence of permanganate reduction rate on organic substrate structure.

Filtration↗
PubMed1979

A spectropolarimetric assay of (-)-adrenaline in compendial formulations.

A method is described for the determination of (-)-adrenaline in certain formulations containing adrenaline hydrogen tartrate at concentrations down to 0.18 mg ml-1 (1:10 000 adrenaline). The assay is based upon a spectropolarimetric measurement at 249 nm of sample solutions, suitably treated to remove interfering substances. The rotation of the sample solutions is corrected for the rotation of the tartaric acid species which is determined by a difference rotation measurement on equimolar sample solutions at pH 1.1 and pH 5.6. The concentration of (-)-adrenaline in the sample is calculated from the net rotation at 249 nm due to the (-)-adrenaline and the total concentration of adrenaline (+)-and (-)-isomers) determined by a published spectrofluorimetric method. The assay is specific for (-)-adrenaline in the presence of (+)-adrenaline, (+)-tartaric acid, adrenaline sulphonic acid and low levels of adrenochrome.

Aerosols↗
PubMedDate not supplied

Method evaluation: automated microscopy as a compendial test for particulates in parenteral solutions.

Accurate enumeration and sizing of contaminant particles in parenteral solutions are critical to the assessment of product quality and suitability for patient use. Current manual microscopic and instrumental (light obscuration) methodologies specified by the USP both result in data of high variability. The microscopic assay for large volume parenterals is time consuming and incorporates an undesirable level of subjectivity; light obscuration counters tend to undersize larger particles and fibers and have low detection efficiency for some particle types commonly present in small volume injections. Light microscopic image analysis is proposed as a method which combines the best features of the two present methods and allows an accurate, precise, and cost effective analysis of parenteral contaminant particles. This paper briefly summarizes the principles of microscopic image analysis and discusses its application in concert with optimized sampling and counting techniques as an improved compendial methodology. Instrument performance requirements are discussed with reference to a number of currently available image analysis systems.

Equipment Design↗
PubMedDate not supplied

Liquid chromatographic determination of medroxyprogesterone acetate in tablets.

A reverse-phase liquid chromatographic method is described for the assay of medroxyprogesterone acetate in tablets. An octadecylsilane (C18) column with a mobile phase of methanol-0.01M dibasic ammonium phosphate (80 + 20 v/v, pH 7.2 +/- 0.1) and photometric detection at 254 nm separates medroxyprogesterone acetate from excipients. Detector responses were linear to concentrations of medroxyprogesterone acetate over the range 50-150 micrograms/mL (r = 0.999). Mean recovery of medroxyprogesterone acetate added to tablet excipients was 100.8%. Mean assay results were 101.3% (n = 3). The assay results are comparable to those obtained by the compendial liquid chromatographic method.

Chromatography, Liquid↗
PubMed1999

[High pressure liquid chromatographic methods for compendium of purity tests].

The paper is addressed to the institute of Pharmaceutical Chemistry, Budapest, on the 50th anniversary of its foundation, paying tribute to Prof. Antal Végh, the first director of the Institute and his first deputy dr. László Auber and all the members of the Staff having merit in developing the research activity at the Department. After surveying the early papers published from the fifties through the seventies, concerning the profile of drug purity control, the factors increasing HPLC selectivity are shortly reviewed. In the concluding part of the paper, some recent results, as HPLC purity control methods suitable for compendial purposes (methylxanthines, opium alkaloids, tropane-alkaloids, enantiomer purity control of different drug compounds on glycoprotein and chirelcel columns) are summarized.

Chromatography, High Pressure Liquid↗
PubMed1975

Information chapters in pharmacopoeias.

Pharmacopoeias have been established by governmental authorities to serve three primary purposes: 1) to compile a select list of currently utilized drugs, including the most efficient forms for their application; 2) to distinguish these articles by convenient and definite names; and 3) to publish objective standards and analytical methods suitable for testing the integrity of commercially available preparations. In addition, some pharmacopoeias also offer informational text intended to instruct pharmacists on the compounding, use, storage and labeling of drugs; to advise physicians about dosage regimens and preferred modes of administration; to counsel producers about good manufacturing practices, and to edify drug analysts by explaining the theories underlying methods employed in compendial tests and assays. Examples of informational chapters in USP XIX are those on Pharmaceutical Dosage Forms, Stability Considerations in Dispensing Practice, and Sterilization. Because of the official status of national pharmacopoeias and their use as regulatory instruments in drug control, pharmacopoeial text intended merely for the information of the reader should be identified as such, and should be separated and distinguished from the mandatory, legally enforceable requirements.

Legislation, Drug↗
PubMed1989

Determination of thymol in halothane anaesthetic preparations by high-performance liquid chromatography.

A high-performance liquid chromatographic (HPLC) procedure has been developed for the isolation and quantification of thymol, a stabilizing agent present in halothane anaesthetic preparations. The method offers improvements in specificity and simplicity with respect to a current official procedure for thymol in halothane. Results for commercial preparations obtained by the proposed procedure demonstrate excellent precision and accuracy with RSD values for replicate analysis ranging from 0.11 to 0.74% and recoveries via fortification from 99.6 to 100.1%. The HPLC method was compared to compendial procedures for thymol bulk substance and halothane products. Chromatographic separation of other related phenolic preservatives used in pharmaceuticals suggests a more extensive application of the proposed procedure.

Chromatography, High Pressure Liquid↗
PubMed1990

Rational limits for drug impurities.

The United States Pharmacopeia (USP) has developed policies on drug substance purity and organic volatile impurities. This paper will include the historical background and the scientific basis of these policies and will give several examples of how they are reflected in the tests that are included in USP monographs. Data on the types of analytical methods used in assessing the purity of compendial articles will also be presented.

Chemical Phenomena↗
PubMed1984

Determination of the chemical constituents and spectral properties of commercial and NF reference standard potassium guaiacolsulfonate: implications of the findings on compendial analytical methodology.

HPLC analysis confirmed a difference in the chemical composition of commercial versus NF reference standard potassium guaiacolsulfonate. After separation by fractional crystallization, the two constituents comprising the former sample were identified by 1H-NMR as potassium guaiacol-4- and -5-sulfonate, respectively. The former isomer predominated. The reference standard material was identified as the 4-sulfonate salt by HPLC, NMR, IR, and UV. This difference raises questions concerning the validity of the compendial identification tests and assay procedure for the drug, which are based on methods requiring direct comparison between it and the reference standard. In fact, the IR test has now been shown to be unreliable as a rigorous criterion for identification, in light of significant differences found in the fingerprint regions of the spectra of the two isomers. However, because the two isomers exhibit identical UV absorption characteristics in solutions of pH less than or equal to 7 (but not in alkaline solution), the compendial UV identification test and assay procedure appear to be valid under the conditions specified. The pKa values of the isolated isomers were estimated by a spectrophotometric method to be 8.74 and 9.16 for the phenolic group of potassium guaiacol-4- and -5-sulfonate, respectively.

Acetylation↗
PubMed1998

Evaluation of various dissolution media for predicting in vivo performance of class I and II drugs.

PURPOSE: In this paper we seek to verify the differences in dissolution behavior between class I and class II drugs and to evaluate the suitability of two new physiologically based media, of Simulated Gastric Fluid (SGF) and of milk for their ability to forecast trends in the in vivo performance of class II compounds and their formulations. METHODS: Dissolution behavior of two class I drugs, i.e. acetaminophen and metoprolol, and of three class II drugs, i.e. danazol, mefenamic acid and ketoconazole, was studied with USP Apparatus 2 in water, SGF, milk, Simulated Intestinal Fluid without pancreatin (SIFsp) and in two media simulating the small intestinal contents in the fed (FeSSIF) and fasted (FaSSIF) states, respectively. RESULTS: Class I powders dissolved rapidly in all media tested. Acetaminophen dissolution in milk was slow from one tablet formulation, in all other cases dissolution was more than 85% complete in 15 minutes. The dissolution rate of metoprolol was shown to be dependent on formulation and manufacturing method, and one of the three tablet formulations did not meet compendial specifications (80%/30 minutes). Dissolution behavior of class II drugs was greatly affected by choice of medium. Dissolution from a capsule formulation of danazol proved to be dependent on the concentration of solubilizing agents, with a the 30-fold increase in percentage dissolved within 90 minutes upon changing from aqueous media without surfactants to FaSSIF. Use of FeSSIF or milk as the dissolution medium resulted in an even greater increase in percentage dissolved, 100 and 180-fold respectively. Dissolution of the weak acid mefenamic acid from a capsule formulation is dependent on both pH and bile salt concentration, which leads to an offset between increased bile salt concentration and lower pH in the fed state compared to the fasted state medium. The weak base ketoconazole showed complete dissolution from a tablet formulation in Simulated Gastric Fluid without pepsin (SGFsp) within 30 minutes, 70% dissolution in 2 hours under fed state simulated upper jejunal conditions but only 6% dissolution in 2 hours under fasted state conditions. CONCLUSIONS: As predicted, dissolution of class II drugs proved to be in general much more dependent on the medium than class I drugs. With the array of compendial and physiological media available, it should be possible to design a suitable set of tests to predict the in vivo dissolution of both class I and II drugs from immediate release formulations.

Acetaminophen↗
PubMed1999

Simultaneous high-performance liquid chromatographic analysis for famotidine, ranitidine HCl, cimetidine, and nizatidine in commercial products.

A high-performance liquid chromatographic (HPLC) procedure for the simultaneous determination of famotidine (FMT), ranitidine HCl (RNT), cimetidine (CMT), and nizatidine (NZT) was developed using a two-level, full-factorial design with three variables (volume of methanol, percentage of triethylamine, and concentration of phosphate buffer) to select an acceptable mobile phase. A column (15 cm x 4.6 mm ID) of Inertsil ODS-2 (5 microns) was used, and 0.04 M aqueous sodium dihydrogen phosphate/acetonitrile/methanol/TEA at a proportion of 345/20/35/0.7 (v/v/v/v) was the selected mobile phase (1 ml/min). The detection wavelength was set at 230 nm, and procaine HCl was used as the internal standard. Precision and linearity of the method were assessed. None of the commercial samples was found to be outside the compendial limits of 90.0% to 110.0% of the claim amount.

Algorithms↗
PubMed1979

GLC determination of trihexyphenidyl hydrochloride dosage forms.

A rapid, sensitive, and specific GLC method for the quantitation of trihexyphenidyl hydrochloride in various pharmaceutical dosage forms is described. The procedure involves chloroform extraction of the active ingredient from a weakly acidic solution, followed by GLC determination using a 3% methyl silicone column. The specificity of the system in relation to several compendial drug analogs also is reported.

Capsules↗
PubMed1975

Determination of mercury-containing pharmaceuticals by vapor phase atomic absorption spectroscopy.

A procedure was developed for the determination of mercurials of pharmaceutical interest. Protic acid cleavage of the compound was followed by reduction of the resulting mercuric ion and vapor phase atomic absorption spectroscopy. This procedure was applied to 11 different mercurial compounds in various pharmaceutical preparations and offers excellent sensitivity with respect to presently used compendial assays. Comparative analytical data between this procedure and compendial methodology are presented.

Chemistry, Pharmaceutical↗
PubMed1975

Determination of estrogens in dosage forms by fluorescence using dansyl chloride.

A sensitive, reproducible, fluorometric procedure for the determination of estrogens in pharmaceutical preparations is presented. The estrogens are determined fluorometrically following their reaction with dansyl chloride. The optimum conditions for the reaction such as pH, reaction solvent composition variations, and speed of reaction are discussed. In addition, a linearity study of the relationship between concentration and fluorescence intensity for estrone, estradiol, and ethinyl estradiol is reported. Solvent extraction procedures based on acid-base behavior or column chromatography are used when necessary to isolate the estrogen prior to reaction with dansyl chloride and fluorometric measurement. The recovery of estrogens from spiked samples indicated that the proposed method is efficient and reproducible. Comparison of the dansyl procedure with the official NF method in the analysis of estrone aqueous suspension showed the proposed method to be accurate and more precise than the NF assay. Estrone aqueous suspension, estradiol in sesame oil, estradiol valerate in castor oil and in sesame oil (in the latter case, in the presence of testosterone), estradiol benzoate in sesame oil, and ethinyl estradiol tablets (0.5 mg/tablet) from commercial sources were satisfactorily analyzed, with average results within compendial limits and no coefficient of variation greater than 2%.

Castor Oil↗
PubMed1988

Application of difference spectroscopy to the determination of some pharmaceutically important nitro compounds.

A simple and selective spectrophotometric method for the determination of some pharmaceutically important nitro compounds has been developed. The suggested method depends upon the spectral changes induced by reduction using either Zn/HCl or Zn/NH4Cl. The different experimental parameters were studied and incorporated into the procedure. The mean percentage recovery ranged from 99 to 101. The proposed method was applied to the determination of the studied compounds in dosage forms, and the results obtained were compared favourably with those given with the compendial ones.

Indicators and Reagents↗