Application of DSC, IST, and FTIR study in the compatibility testing of nateglinide with different pharmaceutical excipients

Experiments were done to assess the compatibility of nateglinide (NTG) with selected excipients in the development of immediate release tablets of NTG by thermal and isothermal stress testing (IST) techniques. To evaluate the drug excipient compatibility, different techniques such as differential scanning calorimetric (DSC) study, infrared (IR) spectrophotometric study, and IST were adopted. The results of DSC study showed that magnesium stearate exhibited some interaction with NTG. However, the results of IR and IST studies showed that all the excipients used in the formula were compatible with NTG. The optimized formulation developed using the compatible excipients were found to be stable after 3 months of accelerated stability studies (40 ± 2 °C and 75 ± 5% RH). Overall, compatibility of excipients with NTG was successfully evaluated using the combination of thermal and IST methods and the formulations developed using the compatible excipients was found to be stable.     

Compatibility study between ibuprofen and excipients in their physical mixtures

The thermal techniques of analysis were used to assess the compatibility between ibuprofen (IB) and some excipients used in the development of extended released formulations. This study is a part of a systematic study undertaken to find and optimizes a general method of detecting the drug–excipient interactions, with the aim of predicting rapidly and assuring the long-term stability of pharmaceutical product and speeding up its marketing. The thermal properties of IB and its physical association as binary mixtures with some common excipients were evaluated by thermogravimetry/derivative thermogravimetry (TG/DTG) and differential scanning calorimetry. FT-IR spectroscopy and X-ray powder diffraction (XRPD) were used as complementary techniques to adequately implement and assist in interpretation of the thermal results. Based on their frequent use in preformulations nine different excipients: starch; microcrystalline cellulose (PH 101 and PH 102); colloidal silicon dioxide; lactose (monohydrate and anhydre); polyvinylpyrrolidone; magnesium stearate and talc were blended with IB. The samples were prepared by mixing the analyte and excipients in a proportion of 1:1 (w:w). The TG/DSC curves of the IB have shown a single stage of mass loss between 175 and 290 °C, respectively, an endothermic peak at 78.5 °C, which corresponds to the melting (literature T _m = 75–78 °C).     

Compatibility of medroxyprogesterone acetate and pharmaceutical excipients through thermal and spectroscopy techniques

Studies of active drug-excipient compatibility represent an important phase in the preformulation stage of the development of all dosage forms. For the development of conjugation estrogens and medroxyprogesterone acetate (MPA) double-layer tablets, techniques of thermal, isothermal stress testing (IST), and molecular vibrational spectroscopy analysis were performed to access the compatibility. Differential scanning calorimetry (DSC) studies were used as an important and complementary tool during preformulation to determine drug-excipient compatibility. On the basis of DSC results, MPA was found to be compatible with polyethylene glycol 6000. However, the results of Raman and IST studies showed that all the excipients defined in the prototype formula were found to be compatible with MPA. Overall, the compatibility of selected excipients with MPA was successfully evaluated using a combination of thermal and IST methods, and the formulations developed using the compatible excipients were found to be stable.     

Compatibility of sildenafil citrate and pharmaceutical excipients by thermal analysis and LC–UV

The evaluation of sildenafil citrate (SC), the best-selling drug for treatment of impotence, for compatibility with various excipients was investigated using thermal and isothermal stress testing. Differential scanning calorimetry (DSC), hot-stage microscopy (HSM) and liquid chromatography (LC) with ultraviolet detection were successfully employed to investigate the compatibility between SC and various excipients commonly used in solid form in the pharmaceutical industry. The studies were performed using 1:1 (m/m) drug/excipient physical mixtures and samples were stored under accelerated stability conditions (40 °C at 75% relative humidity). All excipients tested (such as colloidal silicon dioxide, croscarmellose sodium, lactose, mannitol and sucrose) showed potential incompatibilities by DSC and LC analysis after accelerated stability testing. However, some incompatibilities were not detected by the DSC method and were observed only when LC analysis was performed. HSM was able to differentiate active pharmaceutical ingredient degradation from solubilisation, supporting the interpretation of DSC in excipients where thermal events either overlapped or disappeared. The combination of both the analytical techniques (DSC and LC) and use of a stability chamber is extremely helpful in detecting incompatibilities and providing more robust and accurate approaches for pre-formulation studies.     

Study of stability and drug-excipient compatibility of diethylcarbamazine citrate

Diethylcarbamazine citrate (DEC) is the main drug used in the lymphatic filariasis treatment. This study aimed to evaluate drug-excipient compatibility of binary mixtures (BMs) (1:1, w/w), initially by differential scanning calorimetry (DSC), and subsequently, if there were any interaction evidence, by complementary techniques, such as thermogravimetric (TG), non-isothermal kinetics, Fourier transform infrared (FT-IR), and X-ray diffraction (XRD). For the analyses of the BMs by DSC, we selected those with Tabletose^®, representing the excipients containing lactose, polivinilpirrolidona (PVP), and magnesium stearate (MgS). The additional analyses by FT-IR and XRD showed no interaction evidence. The TG curves of DEC–Tabletose^® showed no signs of interaction, unlike the TG curves of PVP and MgS, confirming the results of non-isothermal kinetics, in which the BMs with PVP and MgS decreased the reaction activation energy. Thus, it was concluded after evaluation that the excipients, especially the PVP and MgS, should be avoided.     

Compatibility study between indomethacin and excipients in their physical mixtures

Thermal analysis is a routine method for analysis of drugs and substances of pharmaceutical interest. Thermogravimetry/derivative thermogravimetry (TG/DTG) and differential scanning calorimetry (DSC) are thermoanalytical methods which offer important information about the physical and chemical properties of drugs (purity, stability, phase transition, polymorphism, compatibility, kinetic analysis, etc.). This work exemplifies a general method of studying the drug-excipient interactions with the aim of predicting rapidly and inexpensively the long thermal stability of their mixtures. The TG/DTG and DSC were used as screening techniques for assessing the compatibility between indomethacin (IND) and its physical associations as binary mixtures with some common excipients. Based on their frequent use in preformulations eleven different excipients: corn starch, microcrystalline cellulose (PH 101; PH 102), colloidal silicon dioxide, lactose (monohydrate and anhydre), polyvinilpyrrolidone K30, magnesium stearate, talc, stearic acid, and manitol were blended with IND. The samples were prepared by mixing the analyte and excipients in a proportion of 1:1 (w:w). In order to investigate the possible interactions between the components, the thermal curves of IND and each selected excipient were compared with those of their 1:1 (w/w) physical mixtures. FT-IR spectroscopy and X-ray powder diffraction were used as complementary techniques to adequately implement and assist in interpretation of thermal results. On the basis of thermal results, confirmed by FT-IR and X-ray analyses, a possible interaction was found between IND with polyvinylpyrrolidone K30, magnesium stearate, and stearic acid.     

Compatibility study of quetiapine fumarate with widely used sustained release excipients

The drug-excipient compatibility study of quetiapine fumarate, with widely used sustained release excipients, was carried out employing differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR). The selected excipients were HPMC K100M, sodium alginate, xanthan gum, Eudragit RSPO, hydrogenated castor oil, carnauba wax, and PEO WSR 303. Equal proportion of drug and excipients was utilized in the interaction study. FT-IR spectra indicated the absence of interaction between drug and excipients. The DSC curve showed a sharp endothermic melting peak at 173.26 °C for quetiapine fumarate. Post melting interaction was observed for carnauba wax, Eudragit RSPO, and hydrogenated castor oil probably due to solubilization of drug in the melted excipient. No interaction was observed for other excipients. The physical mixtures stored at 30 ± 2 °C/65 ± 5% RH did not show any significant degradation of the drug. The concept of systemically conducted preformulation studies will facilitate dossier submission to the drug control authority.     

Selection of excipients for dispersible tablets of itraconazole through the application of thermal techniques and Raman spectroscopy

For the development of dispersible tablets of itraconazole (ITR), techniques of thermal, Raman spectroscopy, and isothermal stress testing (IST) were used to assess the compatibility of ITR with selected excipients. Initially, differential scanning calorimeter (DSC) was used to evaluate the compatibility. Raman spectrum of drug–excipient mixture was also compared with that of pure drug and excipient. Compatibility of excipients defined in the prototype formula was tested using IST. Based on the DSC results alone, PEG-4000 was found to exhibit interaction with ITR. However, the results of Raman and IST studies showed that all the excipients used in the formula were compatible with ITR. Overall, compatibility of excipients with ITR was successfully evaluated using the combination of DSC, Raman spectroscopy, and IST techniques.     

Physicochemical characterization of dipeptidyl peptidase-4 inhibitor alogliptin in physical mixtures with excipients

Alogliptin (ALG) is a hypoglycemic drug used in diabetes which inhibits the enzyme dipeptidyl peptidase-4 (DPP-4), preventing the degradation of incretins, stimulating insulin secretion. The physicochemical characteristics of ALG were evaluated by differential scanning calorimetry (DSC), thermogravimetry (TG) and scanning electron microscopy equipped with energy-dispersive X-ray spectrometer (SEM/EDS). The compatibility studies were carried out between ALG and excipients (physical mixtures, 1:1) using DSC, TG, diffuse reflectance Fourier transform infrared spectroscopy (FTIR), X-ray powder diffraction (XRPD) and hot-stage microscopy. ALG presented purity near to 99%, melted in the range of 179.4–187.2 °C, followed by decomposition which started in 198.0 °C. SEM/EMS analysis of ALG presented irregular crystals and traces of impurities as copper and lead. DSC investigations obtained by physical mixtures showed minor alterations in the melting ranges of ALG with mannitol, magnesium stearate and commercial tablets. Solubilization of ALG in the fused excipient was observed by hot-stage microscopy between mannitol and ALG, and in tablets. The interaction observed in the mixture with magnesium stearate is due to the melting of the excipient and drug separately, first the excipient and then the drug. FTIR showed additional bands related to the excipients. XRPD proved that ALG has a crystal form and no alterations in the ALG profile were observed after the mixtures. ALG was compatible with all excipients tested. These results were important to understand the characteristics, stability and compatibility of the drug, and proved to be useful in preformulation studies.

     

Pharmaceutical approaches involving carvedilol characterization,compatibility with different excipients and kinetic studies

This study was performed to investigate the physical–chemical characteristics of carvedilol (CRV), complemented by compatibility studies with a great variety of pharmaceutical excipients. Thermogravimetry and differential scanning calorimetry, supported by diffuse reflectance infrared fourier transform spectroscopy (DRIFT), X-ray powder diffraction, and scanning electron microscopy (SEM) were selected as the solid-state techniques for the intended analyses. In addition, non-isothermal methods were employed to investigate kinetic data of CRV decomposition process under nitrogen and air atmospheres. CRV is characterized by an endothermic sharp event (T _peak = 389.81 K and ΔH _fusion of ?176.28 J g^?1) and a thermal decomposition behavior in two stages, totalizing 98 % of mass loss. The CRV pattern diffraction presents prominent peaks at 2θ: 5.92°, 14.90°, 18.62°, 24.47°, and 26.30°, and the DRIFT spectrum showed the main characteristics bands for CRV chemical functional groups. The SEM photomicrographs demonstrate that CRV is characterized by irregular blocky shaped crystals. Zero order kinetics was determined by Ozawa method in both nitrogen and air atmospheres. The compatibility results showed no evidence of any incompatibility among CRV and all the excipients analyzed.     

Characterization and compatibility study of desloratadine

Desloratadine (DL) is a selective antagonist of the histamine H₁ receptor, which has been widely used to treat allergic symptoms, and stands out from other drugs in this therapeutic class because it does not cause sedative effects. In the present study, the physico-chemical properties of DL were fully characterized using six analytical techniques such as Differential Scanning Calorimetry (DSC), Thermogravimetric analysis (TG/DTG), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, Powder X-ray diffraction (PXRD), and scanning electron microscopy (SEM). The DSC curve shows a sharp endothermic event at 158.4 °C, and the TG/DTG curve presents two decomposition events between 178.4 and 451.9 °C. A compatibility study involving DL and nine pharmaceutical excipients generally used in pharmaceutical formulations was performed. Physical binary mixtures of DL with each excipient were prepared in a 1:1 (w/w) ratio. After preparation, the samples were analyzed immediately and the results reveal solid-state interaction with anhydrous lactose, microcrystalline cellulose, magnesium stearate, and stearic acid.     

Application of thermal analysis in study of binary mixtures with metformin

Thermal analysis is an essential analytical tool in development of new formulations as well as to study the interaction between drugs and excipients. This work aims to investigate the possible interactions between metformin and excipients as microcrystalline cellulose (Microcel MC101®), starch sodium glycolate (Explosol®), sodium croscarmellose (Explosel®), PVP K30, magnesium stearate, starch and lactose, usually employed in pharmaceutical products. TG, DSC and DTA techniques were used for the thermal characterization to track if the thermal properties of the drug substance were modified in the mixture. Disregard of the starch and lactose systems, no changes in thermal behavior of mixtures were found. Thermogravimetric studies (TG) of metformin and its binary mixtures showed different thermal behavior.     

Fourier transform infrared spectroscopy supported by multivariate statistics in compatibility study of atenolol with excipients

The objective of this study was to use Fourier transform infrared spectroscopy (FTIR) and multivariate statistics to investigate compatibility/incompatibility of atenolol as a representative of active pharmaceutical ingredients and excipients, such as β-cyclodextrin, methylcellulose, starch and chitosan, when used in solid dosage formulations. Two-component physical mixtures consisting of atenolol and selected excipients were studied by FTIR spectroscopy and two methods of multivariate statistical analysis – principal component analysis (PCA) and cluster analysis (CA), which were used as a supplementary tool for interpretation of the FTIR spectra. Taking into account variability explained by the first two principal components, the results of PCA were visualized in the form of a bi-dimensional scatterplot. A lack of interaction was confirmed by two distinct clusters created by both atenolol and a particular excipient with their mixtures. In the case of CA, lack of interaction between both ingredients was also indicated by two large clusters at a level of 33 or 66% of the maximum distance. The results of the investigations show that with the exception of β-cyclodextrin, the remaining excipients are compatible with atenolol. These findings were confirmed by complementary methods, such as differential scanning calorimetry, thermogravimetry and X-ray powder diffraction.     

Preformulation studies on grewia gum as a formulation excipient

Grewia gum is a naturally occurring polysaccharide which has potential as a pharmaceutical excipient. Differential scanning calorimetry and Fourier transform infrared (FT-IR) spectroscopy techniques were used to examine the thermal and molecular behaviours, respectively, of mixtures of grewia gum with cimetidine, ibuprofen or standard excipients, to assess potential interactions. No disappearance or broadening of the melting endotherm was seen with cimetidine or ibuprofen. Similarly, there was no interaction between grewia gum and the standard excipients tested. The results obtained using thermal analyses were supported by FT-IR analysis of the material mixtures. Grewia gum is an inert natural polymer which can be used alone or in combination with other excipients in the formulation of pharmaceutical dosage forms.     

Thermotropic phase behaviour of mixed liposomes of archaeal diether and conventional diester lipids

During preformulation studies of pharmaceutical solid dosage forms, thermal analysis techniques are very useful to detect physical or chemical incompatibilities between the drug and adjuvants of interest that might interfere with efficacy and safety of the final drug product. Differential scanning calorimetry (DSC) and thermogravimetry (TG) are useful tools for this purpose. The aim of this study was to investigate the thermoanalytical behavior of olanzapine (OLZ) when mixed with several excipients commonly used in solid dosage forms such as microcrystalline cellulose, croscarmellose, dicalcium phosphate dihydrate (DCPD), lactose, magnesium stearate, and povidone. Following DSC and TG analyses, powder X-ray diffraction tests were carried out. Thermoanalytical methods showed evidence of interaction between OLZ and magnesium stearate, lactose, and povidone. These results can be useful during the selection of excipients for pharmaceutical formulation development.     

tudy on compatibility of imatinib mesylate with pharmaceutical excipients

Differential scanning calorimetry and thermogravimetric analysis with the support of X-ray powder diffraction and infrared spectroscopy were used as screening techniques for the compatibility testing of imatinib mesylate, with following excipients: magnesium stearate, polyvinylpyrrolidone, microcrystalline cellulose. In order to maximize the probability of interactions 1:1 (by mass) drug: excipient binary mixtures were analysed and compared to individual components. Additionally an influence of storage at temperatures of 25 and 40°C on physico-chemical stability on drug – excipient binary mixtures was investigated. The largest visible changes were observed in the DSC curves of imatinib mesylate – magnesium stearate mixtures.     

Polymorphic screen and drug–excipient compatibility studies of the antichagasic benznidazole

The purpose of this study was to investigate the polymorphism and compatibility of benznidazole (BNZ), a drug used in the treatment of Chagas disease. This drug was subjected to a polymorphic screen using a number of solvents and precipitation procedures to explore the possible existence of different crystal structures of BNZ. The compatibility of BNZ with selected pharmaceutical excipients was evaluated in binary mixtures, in a ratio of 1:1 (w/w). These results were then analyzed with a variety of techniques, including differential scanning calorimetry, Fourier transform infrared spectroscopy, and X-ray powder diffractometry. No polymorphic forms of BNZ were detected despite some observed changes in the DSC profile. The thermal data indicate interaction of the drug with excipients hydroxyethylcellulose, polyethylene glycol, and hydroxypropyl-β-cyclodextrin. Additional studies using infrared spectroscopy confirm the incompatibility of BNZ with only the polyethylene glycol. This excipient should not be used in the development of solid dosage forms containing BNZ.     

Compatibility study of the acetylsalicylic acid with different solid dosage forms excipients

This study is part of a research project aimed to find and optimize methods by which drug-excipient compatibility can be reliably and quickly assessed. The objective of the present study was to evaluate the compatibility of the acetylsalicylic acid (ASA), an non-steroidal anti-inflammatory drug, with pharmaceutical excipients of common use including diluents, binders, disintegrants, lubricants and solubilising agents. In order to investigate the possible interactions between ASA and eleven excipients differential scanning calorimetry (DSC) and thermogravimetry/derivative thermogravimetry analysis completed by Fourier transform infrared spectroscopy (FT-IR) and X-ray powder diffraction were used for compatibility study. The DSC has proven to be, among the selected analytical techniques, the most sensitive and specific in assessing the compatibility. The samples, as physical mixtures, were prepared by mixing the analyte and excipients in a proportion of 1:1 (w:w). On the basis of thermal results (especially DSC), confirmed by FT-IR and X-ray analysis, a possible chemical interaction was found between the ASA with polyvinylpyrrolidone K30 (PVP) and magnesium stearate, respectively a possible physical interaction with colloidal silicon dioxide and stearic acid (Ac. St.).     

Thermal characterization and compatibility studies of itraconazole and excipients for development of solid lipid nanoparticles

The current study was performed to investigate possible interactions between triazole antifungal drug itraconazole (ITR) with selected excipients commonly used for development of solid lipid nanoparticles. The excipients included common lipids (glyceryl behenate (Compritol 888 ATO?), glyceryl monostearate, stearic acid, and cetyl palmitate), charge inducers (dicetyl phosphate and stearlyamine), and surfactants (sodium cholate and sodium deoxycholate). Differential scanning calorimetry, isothermal stress testing, Fourier transform infrared spectral analysis, optical microcopy, and X-ray powder diffraction analysis were performed for assessing the compatibility between the drug and the excipients. Results of the study suggest that the stearic acid exhibited drug–excipient interactions, whereas all other excipients used in the study were found to be compatible with ITR.