Statistical Approaches for Dissolution Profile Comparisons of Metformin Film-Coated Tablets

The objective of this work was to apply several statistical approaches to profile comparison on dissolution data of Metformin immediate release film-coated tablets to assure that the developed formulation of the test product that is similar to the reference product (Glucophage film-coated tablets). The evaluated medicinal product belongs to BCS Class III (high solubility, low permeability). The similarity testing of the dissolution profile was performed on the highest strength of the dosage form, following the regulatory requirements for bioequivalence study. The obtained results showed that the simple standard difference and similarity (f1 and f2)-factors are not applicable and therefore practically not useful for comparison of dissolution profiles because one of the regulatory requirements that the relative standard deviation or coefficient of variation of any product should be less than 20% for the first point and less than 10% from second to last time point, which was not achieved in the present case. Therefore, more advanced multivariate methods such as model-dependent approaches coupled to multivariate statistics, the multivariate model-independent approach based on generalized statistical distance (such as e.g. Mahalanobis distance) have been applied for evaluation of dissolution profiles. This approach appeared to provide extra arguments when deciding if two profiles are similar, as it allows for a better description of the dissolution processes (in the sense of e.g. the rate and amount of the active substance dissolved) and thus a better prediction of in vivo performance. Comparison with traditional methods such as those based on fit-factors is made, and their shortcomings pinpointed out. Dissolution profiles can be tested for differences in both level and shape by multivariate-based methods and these methods provide detailed information about dissolution data, which can be useful also in formulation development to achieve the final goal – match the actual performance of the released test product to the performance of a target reference product.publishedVersio

Green Strategies toward Eco-Friendly HPLC Methods in Pharma Analysis

The global need for changing the processes in order to meet the green analytical chemistry (GAC) criteria is a great challenge for the pharmaceutical industry. High-performance liquid chromatography (HPLC), as one of the most frequently used techniques in various stages in the pharmaceutical industry, generates huge amounts of organic toxic waste. Therefore, the implementation of the GAC principles in pharma analysis is highly required. Although the number of published papers concerning green chromatography approaches is constantly increasing, the use of eco-friendly HPLC methods in the pharma industry has not been widely implemented. The reasons for this mainly include the need for adaptation of the conventional HPLC instruments, lack of time, lack of experience, or uncertainty of the analysts regarding fulfillment of the method criteria. In this chapter, an overview of green strategies that can be easily applied to conventional instruments for liquid chromatography (LC) in developing eco-friendly HPLC methods in pharma analysis is given. The aim is to emphasize that the green method development in pharma analysis can be easily accomplished and to encourage the analytical community in the pharmaceutical industry not only to develop but also to transfer the already established conventional HPLC methods into green ones

Proučavanje stvaranja agregata rekombinantnog humanog granulocitnog faktora stimulacije kolonija (rHuG-CSF), lenograstima, pomoću kromatografije isključenjem prema veličini i SDS-PAGE

The stability of proteins is a subject of intense current interest. Aggregation, as a dominant degradation pathway for therapeutic proteins, may cause multiple adverse effects, including loss of efficacy and immunogenicity. In the present study, the formation of aggregates in lenograstim under physiological conditions was monitored. For this purpose, a simple and selective size-exclusion high-performance liquid chromatography method for detection and separation of aggregates from intact protein was developed. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis was performed under reducing and non-reducing conditions to determine the nature of aggregate bond formation. Using both techniques, the presence of a low aggregate content attached via disulfide bonds was detected.Stabilnost proteina vrlo je aktualna problematika. Agregacija, kao dominantni put razgradnje terapijskih proteina, može uzrokovati različite nuspojave, koje uključuju i gubitak učinkovitosti imunološkog sustava. U ovom radu praćeno je stvaranje agregata u lenograstimu pod fiziološkim uvjetima. Razvijena je jednostavna i selektivna tekućinska kromatografija visoke djelotvornost s isključenjem prema veličini za detekciju i razdvajanje agregata od intaktnog proteina. Pomoću natrij-dodecil sulfat poliakrilamidne gel elektroforeze u reducirajućim i nereducirajućim uvjetima utvrđen je način stvaranja agregata. Pomoću obje tehnike moguće je detektirati prisutnost malih količina agregata koji su spojeni disulfidnim vezama

Development and validation of RP-HPLC assay of chlorhexidine in gingival crevicular fluid

A reversed - phase HPLC method with UV detection for determination of chlorhexidine in gingival crevicular fluid (GCF) was optimized and validated, using chlorpheniramine as an internal standard. The chromatographic separation was performed on Discovery C18 HPLC column with 0.01 mol L-1 phosphate buffer (pH=3.0), triethylamine and acetonitrile (66:1:33, V/V/V), as mobile phase. Under the optimized HPLC conditions, linearity was obtained in the range of 0.5-5.0 μg mL-1 with LOD 0.07 μg mL-1 and LLOQ 0.5 μg mL-1. The described method can be successfully applied for determination of chlorhexidine concentrations in GCF obtained from patients with chronic periodontal disease treated with PerioChipTM

RP-HPLC method with indirect UV detection for determination of sodium ibandronate in pharmaceuticals

Ibandronate sodium (IBN) [(1-hydroxy-3- (methyl pentyl amino) propylidene bisphosphonic acid monosodium monohydrate)] is the sodium salt of ibandronic acid, a synthetic nitrogen-containing bisphosphonate drug. The aim of this study was to develop a sensitive and accurate RP-HPLC method for determination of IBN in pharmaceutical formulations. Chromatographic separation was performed on a Waters Bridge column C18 (250 mm x 4,6 mm I. D.; particle size 5 µm) in an isocratic mode with a mobile phase was consisted of 90 % buffer: 10 % ACN (v/v). The buffer was made using 1.5 ml ortho-phosphoric acid, 990 mg 1-hexanesulfonic acid sodium salt 98%, 140 mg EDTA in 1000 ml flask diluted with HPLC grade water. The elution was carried out at a flow rate of 1.0 mL/ min. A diode array detector measured the UV absorbance at 198 nm, in inverse mode. The method was validated for specificity/ selectivity, linearity, LOD, LOQ, accuracy, precision, and robustness according to ICH validation guidelines. The limits of detection and quantification were calculated at 0.0163 µg/ml and 0.0495 µg/ml, respectively. The method was effectively used for determination of IBN from commercial tablets and provided good results without any interference from commonly used excipients

Optimization of method for simultaneous multi-element determination of trace elements by Inductively Coupled Plasma-Optical Emission Spectrometry: Chemometric approach

Two objective functions for multi-element optimization in ICP-OES were used and compared using signal-to-background ratios as a figure of merit. Three dimensional response surfaces were generated for a number of elements (Fe, Zn, Cu, Se, Mn, Cr, Ni and Co) to evaluate the performance of both objective functions in locating the optimum compromise instrumental operating conditions in multielement determinations. IEC technique was used for correction of spectral interferences. Validation of the applied method was carried out by determination of linearity (1 to 100 μg/l), accuracy, precision, detection and quantification limit for each element. Detection limit was calculated using SBR-RSD approach. Both objective functions gave the same set of instrumental operating conditions for simultaneous multi-element determination as the best compromis

Quantitative determination of glycyrrhizinic acid by square-wave

Novel adsorptive stripping square-wave voltammetric method as well as a new high-pressure liquid chromatographic method for direct determination of glycyrrhizinic acid in dosage pharmaceutical preparation, used against virus infections, have been developed. Glycyrrhizinic acid is an electrochemically active compound, which undergoes irreversible reduction on a mercury electrode surface in an aqueous medium. Its redox properties were studied thoroughly by means of square-wave voltammetry, as one of the most advanced electroanalytical technique. The voltammetric response depends mainly on the pH of the medium, composition of the supporting electrolyte, as well as the parameters of the excitement signal. It was also observed that the voltammetric properties strongly depend on the accumulation time and potential, revealing significant adsorption of glycyrrhizinic acid onto the mercury electrode surface. Upon this feature, an adsorptive stripping voltammetric method for quantitative determination of glycyrrhizinic acid was developed. A simple, sensitive and precise reversed phase HPLC method with photodiode array UV detection has also been developed, mainly for comparison and conformation of the results obtained with the voltammetric method