A stability-indicating HPLC method to determine cyproterone acetate in tablet formulations

Mini Review on Forced Degradation Studies on Anti-Epileptic Drugs and Beyond

In this review on the forced degradation studies on anti-epileptic drugs and the development of validated stability-indicating assay methods for drug substances and products at a condition more severe than accelerated condition (i.e. 40 ± 2°C, 75 ± 5% relative humidity), the drug substance and drug product undergo degradation is known as forced or stress degradation. To know about the impurities developed during the storage of drug products in various environmental conditions. The limit of degradation allowable is 5-20%. More than 20% of degradation is abnormal and must be investigated. Any regulatory guidelines do not mention the pH conditions for acid or base hydrolysis, the temperature for thermal degradation or the concentration of the oxidation agent. Only International Conference on Harmonization (ICH) guidelines Q1B photostability stability and states that light sources must be a combination of UV and visible light. The shortcomings of mentioned techniques with appreciation to regulatory necessities are highlighted. A systematic method for the forced degradation studies on anti-epileptic drugs such as "Topiramate, Vigabatrin, Lacosamide, Tiagabine, Levetiracetam and Zonisamide" is discussed. This review helps researchers to get an idea about stability-indicating methods of development and validation for newer antiepileptic drugs and the characteristics of drug products that degrade under specific degradation conditions.

A molybdenum disulfide-reduced graphene oxide nanocomposite as an electrochemical sensing platform for detecting cyproterone acetate

Based on the synergistic effect of MoS2 and rGO, a MoS2-rGO nanocomposite film shows a wide linear range and high sensitivity towards cyproterone acetate.

Evaluation of an eucalyptus oil containing topical drug delivery system for selected steroid hormones

In the present study the permeation and the chemical stability of 17-beta-estradiol, progesterone, cyproterone acetate and finasteride incorporated in an eucalyptus oil containing microemulsion system have been investigated. The formulations contained 1% (w/w) of the steroid hormones. Self diffusion coefficients determined by pulsed-field-gradient spin echo NMR spectroscopy were used to characterise the microemulsion. From these results a bicontinuous structure is proposed for the multicomponent system. However a correlation between the self diffusion of the hormones in the vehicle and the transdermal flux was not indicated. Explanations for this were self assembling, formation of aggregates between the components of the microemulsion and drugs and different effects because of different solubility of the drugs. By addition of certain polymers the skin permeation rates could be improved with exception of cyproterone acetate. Beside standard diffusion experiments, the residual drug content in the skin was investigated. Drug stability was monitored by analysing the steroid hormone content in the different formulations over an observation period of 6 weeks and could be improved by polymers. In addition, viscosity measurements were performed. They indicated an influence of the polymers and drugs on the viscosity in all formulations.

Skin permeation of different steroid hormones from polymeric coated liposomal formulations

In this study, the effect of various polymers (polycarbophil, chitosan-EDTA, polymeric emulsifier and carrageenan) on the permeation, the chemical and microbial stability of 17-beta-estradiol, progesterone, cyproterone acetate (cpa) and finasteride incorporated in DPPC (1,2-dipalmitoyl-sn-glycero-3-phosphocholine) liposomes has been investigated. The liposomes contained 1% (w/w) of the steroid hormones. Standard diffusion experiments were performed. Drug stability was monitored by analysing the steroid hormone content in the different formulations over a time period of 8 weeks and visually inspecting for microbial contamination. In addition, viscosity measurements were performed. The permeation rate could be improved by addition of polymeric agents depending on their type and drug. In all tested formulations, finasteride exhibited the highest diffusion. Both the chemical and the microbial stability of the hormones were significantly improved by the polymers in comparison to the pure liposomes after an observation period of 8 weeks. After that time microbial stability was still evident for all semisolid formulations. In contrast to this in the pure liposomes already after 2 weeks the steroid drugs showed complete insufficient chemical stability and microbial contamination. Additional rheological measurements indicated an influence of the polymers and drugs on the viscosity in all formulations. The elasticity predominated in nearly all polymeric formulations.

Recent Advances in the Analysis of Steroid Hormones and Related Drugs

The development during the last 15 years and the state-of-the-art in the analysis of bulk steroid hormone drugs and hormone-like structures and pharmaceutical formulations made thereof are summarized. Other steroids (sterols, bile acids, cardiac glycosides, vitamins D) as well as biological-clinical aspects and pharmacokinetic and metabolic studies are excluded from this review. The state-of-the-art is summarized based on comparisons of monographs in the latest editions of the European Pharmacopoeia, United States Pharmacopoeia and the Japanese Pharmacopoeia. This is followed by sections dealing with new developments in the methodology for the fields of spectroscopic and spectrophotometric, chromatographic, electrophoretic and hyphenated techniques as well electroanalytical methods. The review is terminated by two problem-oriented sections: examples on impurity and degradation profiling as well as enantiomeric analysis.

Fully automated method for the liquid chromatographic determination of cyproterone acetate in plasma using restricted access material for sample pre-treatment

A new fully automated method for the quantitative analysis of an antiandrogenic substance, cyproterone acetate (CPA), in plasma samples has been developed using on-line solid-phase extraction (SPE) prior to the determination by reversed-phase liquid chromatography (LC). The automated method was based on the use of a precolumn packed with an internal-surface reversed-phase packing material (LiChrospher RP-4 ADS) for sample clean-up coupled to LC analysis on an octadecyl stationary phase using a column-switching system. A 200-microL volume of plasma sample was injected directly on the precolumn packed with restricted access material using a mixture of water-acetonitrile (90:10, v/v) as washing liquid. The analyte was then eluted in the back-flush mode with the LC mobile phase which consisted of a mixture of phosphate buffer, pH 7.0-acetonitrile (54:46, v/v). The elution profiles of CPA and blank plasma samples on the precolumn and the time needed for analyte transfer from the precolumn to the analytical column were determined. Different compositions of washing liquid and mobile phase were tested to reduce the interference of plasma endogenous components. UV detection was achieved at 280 nm. Finally, the developed method was validated using a new approach, namely the application of the accuracy profile based on the interval confidence at 90% of the total measurement error (bias+standard deviation). The limit of quantification of cyproterone acetate in plasma was determined at 15 ng mL(-1). The validated method should be applicable to the determination of CPA in patients treated by at least 50 mg day(-1).

Development of validated stability-indicating assay methods--critical review

This write-up provides a review on the development of validated stability-indicating assay methods (SIAMs) for drug substances and products. The shortcomings of reported methods with respect to regulatory requirements are highlighted. A systematic approach for the development of stability-indicating methods is discussed. Critical issues related to development of SIAMs, such as separation of all degradation products, establishment of mass balance, stress testing of formulations, development of SIAMs for combination products, etc. are also addressed. The applicability of pharmacopoeial methods for the analysis of stability samples is discussed. The requirements of SIAMs for stability study of biotechnological substances and products are also touched upon.

Characterization of an unknown component in Noscapine using liquid chromatography-mass spectrometry and proton nuclear magnetic resonance spectroscopy

Analytical and semipreparative LC methods were used to quantitate and isolate an unknown component (Impurity A) found in samples of bulk Noscapine. This component was also examined by LC-ESI-MS and 1H-NMR. It was concluded that the structure of Impurity A only differed from Noscapine in that it possessed a hydroxyl group at position 21 of the isobenzofuranone moiety.