Influence of Solid Phase and Formulation Processing on Stability of Abbott-232 Tablet Formulations

Research Progress of Raman Spectroscopy and Raman Imaging in Pharmaceutical Analysis

The analytical investigation of the pharmaceutical process monitors the critical process parameters of the drug, beginning from its development until marketing and postmarketing, and appropriate corrective action can be taken to change the pharmaceutical design at any stage of the process. Advanced analytical methods, such as Raman spectroscopy, are particularly suitable for use in the field of drug analysis, especially for qualitative and quantitative work, due to the advantages of simple sample preparation, fast, nondestructive analysis speed, and effective avoidance of moisture interference. Advanced Raman imaging techniques have gradually become a powerful alternative method for monitoring changes in polymorph distribution and active pharmaceutical ingredient distribution in drug processing and pharmacokinetics. Surface-enhanced Raman spectroscopy (SERS) has also solved the inherent insensitivity and fluorescence problems of Raman, which has made good progress in the field of illegal drug analysis. This review summarizes the application of Raman spectroscopy and imaging technology, which are used in the qualitative and quantitative analysis of solid tablets, quality control of the production process, drug crystal analysis, illegal drug analysis, and monitoring of drug dissolution and release in the field of drug analysis in recent years.

Chemometric study of the excipients' influence on polymorphic-behavior. Mefenamic acid as case of study

The assessment of polymorphism is a problematical issue for regulatory agencies, because variations among crystalline forms of active pharmaceutical ingredient (API) can lead to changes in the efficacy and safety of formulated product. Such conversions are very hard to be detected, thus, the development of techniques for the identification, characterization and quantification of polymorphs results essential in all stages of the manufacturing process. The presence of excipients in formulated products may change the crystal stability of an API, by catalyzing a polymorphic transformation or stabilizing the less stable form. As paradox, all suitable analytical techniques (spectroscopies, thermal analysis, NMR and DRX, and others) for polymorphic analysis are affected by excipients. A deep understanding of the polymorphism-excipient relationship is in full accordance with Quality by Design (QbD) paradigm, the systematic approach focused in quality building into a product based in the full understanding of the products and process. In this work, a novel approach based on thermal stress, MIR monitoring, multivariate curve resolution with alternating least squares (MCR-ALS) and kinetic analysis was developed and applied to monitor polymorphism behavior of model API in formulated products. Commercial tablets, physical mixtures and commercial API, were processed and analyzed under the proposed approach. Commercial tablets of MFA revealed a fast conversion to Form II, contrasting to the behavior of the pure API. Physical mixtures showed similar behavior to commercial tablets, thus reduction in transformation times was related to MFA-excipients physical interaction, even at surface level. Calorimetric studies support the conclusion obtained. The developed approach could be extended to others APIs and other stress sources (humidity, solvents, mechanical forces and its combinations), being a valuable tool for QbD environment.

Undesired co-amorphisation of indomethacin and arginine during combined storage at high humidity conditions

The use of co-amorphous systems for solubility enhancement of poorly water-soluble drugs has recently gained interest in the field of pharmaceutical technology. However, undesired co-amorphisation of a drug may lead to an alteration of the performance of the drug product, e.g. the previously observed co-amorphisation of indomethacin and arginine upon storage of tablets containing both components in an initially crystalline form at room temperature (RT) and 75% relative humidity (RH). Therefore, the aim of the present study was to further investigate this unintended co-amorphisation by storing plain crystalline γ-indomethacin and arginine as well as physical mixtures of both components at RT and three different RH levels (28, 58, and 75% RH). After storage for up to 101 days, their properties were analysed by X-ray powder diffraction, infrared spectroscopy, differential scanning calorimetry, thermogravimetric analysis, and HPLC. Results showed that the solid state of plain γ-indomethacin did not change during storage at all three storage conditions. In contrast, arginine was found to form a dihydrate upon storage at RT/58% RH and RT/75% RH. The physical mixtures, stored at RT/28% RH and RT/58% RH, remained crystalline and were chemically stable, while the formation of a co-amorphous salt between indomethacin and arginine as well as basic hydrolysis of indomethacin started already 1 day after exposure to RT/75% RH. Moreover, formation of a crystalline salt of indomethacin and arginine upon storage at RT/75% RH was observed. As neither of these instabilities occurred, if indomethacin was stored separately, the simultaneous effects of arginine and moisture on the solid state properties and chemical stability of indomethacin should be taken into account, if selecting arginine as excipient.

Unintended and in situ amorphisation of pharmaceuticals

Amorphisation of poorly water-soluble drugs is one approach that can be applied to improve their solubility and thus their bioavailability. Amorphisation is a process that usually requires deliberate external energy input. However, amorphisation can happen both unintentionally, as in process-induced amorphisation during manufacturing, or in situ during dissolution, vaporisation, or lipolysis. The systems in which unintended and in situ amorphisation has been observed normally contain a drug and a carrier. Common carriers include polymers and mesoporous silica particles. However, the precise mechanisms by which in situ amorphisation occurs are often not fully understood. In situ amorphisation can be exploited and performed before administration of the drug or possibly even within the gastrointestinal tract, as can be inferred from in situ amorphisation observed during in vitro lipolysis. The use of in situ amorphisation can thus confer the advantages of the amorphous form, such as higher apparent solubility and faster dissolution rate, without the disadvantage of its physical instability.

Polymorph Discrimination using Low Wavenumber Raman Spectroscopy

Characterization of crystalline polymorphs and their quantitation has become an integral part of the pre-clinical drug development process. Raman spectroscopy is a powerful technique for the rapid identification of phases of pharmaceuticals. In the present work we demonstrate the use of low wavenumber Raman vibrational spectroscopy (including phonon measurement) for discrimination among polymorphs. A total of 10 polymorphic pharmaceuticals were employed to conduct a critical assessment. Raman scattering in the low frequency region (10-400 cm-1), which includes crystal lattice vibrations, has been analyzed and the results indicate lattice phonon Raman scattering can be used for rapid discrimination of polymorphic phases with additional discriminating power compared to conventional collection strategies. Moreover structural insight and conformational changes can be detected with this approach.

Effect of laser irradiation on the stability of a photo-sensitive active pharmaceutical ingredient by Raman microscopy

This study was conducted to investigate the effect of laser beam irradiation from a novel non-confocal laser Raman microscope on the stability of a photo-sensitive drug. The non-confocal Raman microscopy, which irradiates a low-power unfocused laser beam on the surface of the samples by controlling of optical system, was applied to characterize the stability of nifedipine as a photo-sensitive drug model. The time-dependent changes in the Raman spectra of nifedipine were monitored in order to evaluate the degradation of nifedipine during laser irradiation. The results were compared with the Raman spectra measured by using the confocal laser Raman microscopy which irradiates a low-power focused laser beam. The intensity of some peaks in the confocal Raman spectra significantly decreased depending on the irradiation-time length, compared to the non-confocal Raman macroscopic analysis. The photodegradation of nifedipine caused by the laser irradiation followed the first-order kinetics. The degradation rate constants of nifedipine with the non-confocal analysis were lower than those of nifedipine with the confocal analysis. Thus, the novel non-confocal laser Raman microscopy can be applied to reduce the degradation of the photo-sensitive drug during laser irradiation, and the results suggest that the non-confocal laser Raman microscopy will be a useful technique for the measuring of Raman spectra of photo-sensitive materials with a long-term exposure.

Structural and Physicochemical Aspects of Dasatinib Hydrate and Anhydrate phases

Crystal structures for the commercial monohydrate form and an anhydrate form of dasatinib, an oral anti-cancer agent, are presented along with characterization by Raman spectroscopy, powder X-ray diffraction, differential scanning calorimetry, and thermogravimetric analysis. Solubility measurements conducted in water reveal the anhydrate has dramatically improved solubility compared to the commercial hydrate form. Finally, dasatinib is a rare example of a promiscuous solvate former and the basis for this behavior can now be understood by examining the poor packing efficiency in the unsolvated form.

Analysis of solid-state transformations of pharmaceutical compounds using vibrational spectroscopy

Objectives

Solid-state transformations may occur during any stage of pharmaceutical processing and upon storage of a solid dosage form. Early detection and quantification of these transformations during the manufacture of solid dosage forms is important since the physical form of an active pharmaceutical ingredient can significantly influence its processing behaviour, including powder flow and compressibility, and biopharmaceutical properties such as solubility, dissolution rate and bioavailability.

Key findings

Vibrational spectroscopic techniques such as infrared, near-infrared, Raman and, most recently, terahertz pulsed spectroscopy have become popular for solidstate analysis since they are fast and non-destructive and allow solid-state changes to be probed at the molecular level. In particular, Raman and near-infrared spectroscopy, which require no sample preparation, are now commonly used coupled to fibreoptic probes and are able to characterise solid-state conversions in-line. Traditionally, uni- or bivariate approaches have been used to analyse spectroscopic data sets; however, recently the simultaneous detection of several solid-state forms has been increasingly performed using multivariate approaches where even overlapping spectral bands can be analysed.

Summary

This review discusses the applications of different vibrational spectroscopic techniques to detect and monitor solid-state transformations possible for crystalline polymorphs, hydrates and amorphous forms of pharmaceutical compounds. In this context, the theoretical basis of solid-state transformations and vibrational spectroscopy and common experimental approaches are described, including recent methods of data analysis.

Advances in solid dosage form manufacturing technology

Currently, the pharmaceutical and healthcare industries are moving through a period of unparalleled change. Major multinational pharmaceutical companies are restructuring, consolidating, merging and more importantly critically assessing their competitiveness to ensure constant growth in an ever-more demanding market where the cost of developing novel products is continuously increasing. The pharmaceutical manufacturing processes currently in existence for the production of solid oral dosage forms are associated with significant disadvantages and in many instances provide many processing problems. Therefore, it is well accepted that there is an increasing need for alternative processes to dramatically improve powder processing, and more importantly to ensure that acceptable, reproducible solid dosage forms can be manufactured. Consequently, pharmaceutical companies are beginning to invest in innovative processes capable of producing solid dosage forms that better meet the needs of the patient while providing efficient manufacturing operations. This article discusses two emerging solid dosage form manufacturing technologies, namely hot-melt extrusion and fluidized hot-melt granulation.