Microbiological bioassay of erythromycin thiocyanate: optimisation and validation

Brief Overview of Frequently used Macrolides and Analytical Techniques for their Assessment

Background:

Macrolide antibiotics are known as versatile broad-spectrum antibiotics. Macrolides belong to the oldest group of antibacterial agents. The macrolides which are frequently used for clinical purposes are broadly categorized in three classes depending on the number of membered macrocyclic lactone ring. These three classes actually consist of 14, 15 or 16 atoms in macrocyclic lactone ring which are linked through glycosidic bonds. Erythromycin, azithromycin clarithromycin and roxithromycin are frequently used to control against bacterial infections.

Methods:

The quality assurance and quality controls are important tasks in the pharmaceutical industries. Consequently, to check the quality of drugs, there is a strong need to know about alternative analytical methods for the routine analysis. Many methods have been reported in the literature for the quantitative determination of erythromycin, clarithromycin, azithromycin and clarithromycin in pharmaceutical formulations and biological samples.

Results:

This review will cover a brief introduction of erythromycin, azithromycin, clarithromycin and roxithromycin as well as analytical techniques for their assessment. Each developed method has its own merits and demerits.

Conclusion:

Any accurate method could be used for the quality control and quality assurance of macrolide antibiotics according to the availability, performance and procedure of selected instrument as well as skill and expertise of the analyst.

Simultaneous determination of multicomponent of acetylkitasamycin and kitasamycin by LC-MS/MS in swine plasma and its application in a pharmacokinetic study

A simple and reliable LC-MS/MS method was established for simultaneous determination of 12 components from acetylkitasamycin and kitasamycin in swine plasma. The analytes were separated on a Shim-pack VP-ODS column with a 25 min gradient elution using 5 mmol/L ammonium acetate and acetonitrile as the mobile phase at a flow rate of 0.2 mL/min. Identification and quantification were accomplished by electrospray ionization) in positive mode using multiple reaction monitoring. The limits of quantitation of acetylkitasamycin A1 A3 , A13 and kitasamycin A3 , A13 were 3 μg/L, and that of the other eight components was 5 μg/L. The mean recoveries of kitasamycin and acetylkitasamycin ranged from 85.3 to 103.5%. The developed method was successfully applied to a pharmacokinetic study in swine after intravenous (i.v.) and oral (p.o.) administration of acetylkitasamycin. The result showed that the plasma concentrations of acetylkitsamycin components were much higher than that of kitasamycin in swine after i.v. and p.o., in which acetylkitsamycin A4 A5 was the highest component at each time point.

Development and validation of a quantitative cell-based bioassay for comparing the pharmacokinetic profiles of two recombinant erythropoietic proteins in serum

An in vitro cell-based bioassay was developed and validated to assess the pharmacokinetic profiles of two novel therapeutic recombinant proteins (EP1 and EP2) with erythropoiesis stimulating properties in Sprague-Dawley rats. While immunoassays are the standard choice for evaluating the pharmacokinetic parameters of drugs, no immunoassay was available for EP2, necessitating the need for a quantitative bioassay capable of measuring both EP1 and EP2 separately so that appropriate comparisons could be made. The bioassay described here utilizes a sub clone of the murine 32D cell line transfected with the gene encoding for the human erythopoietin (HuEPO) receptor. Erythropoietin (EPO), EP1 and EP2 exert their proliferative effect on the cell line by signaling through the HuEPO receptor. The proliferation induced by the erythropoietic proteins was measured by [methyl-(3)H]thymidine incorporation into the cellular DNA. The assay was conducted in 96-well microtiter plates and had relatively high throughput. The Guidelines of the International Conference on Harmonization (ICH) were followed for the validation of the different assay parameters including robustness, linearity, accuracy, precision, limit of quantitation (LOQ) and specificity. The robustness of the bioassay is demonstrated by the lack of an effect of age of the 32D cell culture on the performance of the EP2 bioassay. The bioassay demonstrated good linearity, yielding a coefficient of determination of 0.99 or higher for both EP1 and EP2. The assay showed reproducible dose-response curves for EP1 in the range of 0.039-2.5 ng/mL and for EP2 in the range of 0.125-8 ng/mL. The accuracy estimates ranged between 98% and 108% for EP1 and between 90% and 110% for EP2 in the reproducible range mentioned above. Intermediate precision (within-plate R.S.D.) in the same range was within 26% and 17% for the EP1 and EP2 bioassays, respectively. The validated bioassays for EP1 and EP2 were utilized to quantitatively analyze serum samples from a pharmacokinetic study conducted to compare the profiles of the two compounds in Sprague-Dawley rats.

Spectrofluorimetric analysis of certain macrolide antibiotics in bulk and pharmaceutical formulations

The macrolides (erythromycin, erythromycin esters, azithromycin dihydrate, clarithromycin and roxithromycin) can be analyzed by a simple spectrofluorimetric method based on the oxidation by cerium(VI) in the presence of sulphuric acid and monitoring the fluorescence of cerium(III) formed at lambda(ex) 255 nm and lambda(em) 348 nm. All variables affecting the reaction conditions as cerium(VI), sulphuric acid concentrations, heating time, temperature and dilution solvents were carefully studied. Linear calibration graphs were obtained in the range of 42.6-1200 ng ml(-1) with a percentage relative standard deviation in the range of 0.014-0.058%. Quantitation and detection limits were calculated. The method was applied successfully for the assay of the studied drugs in pure and pharmaceutical dosage forms as tablets, capsules and suspension. Recovery experiments revealed recovery of 98.3-100.8%. The effect of potential interference due to common ingredients as glucose, sucrose, lactose, citric acid, and propylene glycol was investigated. Applying standard addition method shows a recovery of 97.7-100.9% macrolide antibiotics from their corresponding dosage forms.

Confirmatory method for macrolide residues in bovine tissues by micro-liquid chromatography-tandem mass spectrometry

A new confirmatory method for three macrolides (tylosin, tilmicosin and erythromycin) in bovine muscle, liver and kidney by micro-LC-MS-MS using an atmospheric pressure ionisation source and an ionspray interface has been developed. Roxithromycin was used as internal standard. The molecular related ions, [M+2H]2+, at m/z 435 for tilmicosin, and [M+H]+, at m/z 734 and 916 for erythromycin and tylosin, respectively, were the precursor ions for collision-induced-dissociation and two diagnostic product ions for each macrolide were identified for the unambiguous confirmation by selected reaction monitoring LC-MS-MS. Precision values (relative standard deviations) were all below 14.9%, whereas the overall accuracy (relative error) ranged from -17.7 to -9.8% for tylosin, from -17.5 to -10.7% for tilmicosin and from -19.6 to -13.7% for erythromycin, in all the investigated bovine tissues. The limits of quantification were 30 (muscle) or 40 (liver, kidney) microg kg(-1), 20 (muscle) or 150 (liver, kidney) microg kg(-1), 50 (muscle, liver) or 80 (kidney) microg kg(-1), 20 (muscle, liver) or 50 (kidney) microg kg(-1) for tylosin, tilmicosin, erytromycin and roxithromycin, respectively.

Procedure to evaluate the stability during processing and storage of a medicated premix and medicated farm feed: erythromycin thiocyanate

In this paper, a stability study of a medicated premix and medicated farm feed containing erythromycin thiocyanate was planned. No drug degradation was detected during the medicated farm feed processing. In the medicated premix stability study, significant drug degradation was detected only at 40 degrees C and 75% relative humidity. Because after 2 years of storage at 25 degrees C and 60% relative humidity no degradation of erythromycin thiocyanate was detected, this period of time is proposed as the premix shelf life. In the medicated farm feed stability study, drug degradation was detected under accelerated conditions, but it was not detected under long-term storage conditions for 3 months. Therefore, the proposed shelf life of the medicated farm feed is 3 months, as this is time enough to be consumed. The planned stability study-storage conditions, testing frequency, and proposed data evaluation-allowed an easy and reliable evaluation of veterinary medicine stability.