Differential scanning calorimetry was used to examine the thermal behaviour of mixtures of the drug prochlorperazine with
standard excipients, to assess potential interactions, and of mixtures with cyclodextrins, to investigate inclusion complexation
which could increase the photostability of the drug. For most of the excipients (magnesium stearate, stearic acid, Explotab®, Ac-Di-Sol®, Encompress® and Ludipress®, lactose and Starch 1500) disappearance or broadening of the melting endotherm of the drug indicated interactions. Lubritab® was the only 'inert' excipient tested. Mixtures of prochlorperazine and the cyclodextrins gave incomplete inclusion complexation
as shown by only partial disappearance of the melting endotherm of the drug.
The effect of excipients on the secondary structure of lyophilized proteins was studied through second-derivative Fourier
transform infrared (FTIR) spectroscopic analysis. The glass transition temperature (Tg), denaturation temperature (Td) and moisture content were determined by differential scanning calorimetry (DSC) and thermogravimetry (TG). Tg, Td and the preservation of protein secondary structure were found to be dependent upon the type and amount of the excipient
included in the formulation. Meanwhile, the lyophilized proteins easily adsorbed amounts of moisture during storage to reduce
their Tgs and stability.
The 4,6-bis[2′(diethylamino)ethoxy]2,8,10-trimethylpyrido[3,2-g]quinoline (BG 637) is one of the compound from the pyrido[3,2-g] quinolines
family. This compound had in vitro activity against the resistant cells and can reverse the multidrug resistance developed
during the chemotherapeutic treatments.
To characterize BG 637, techniques such as differential scanning calorimetry (DSC), Fourier transform infrared spectrometer
(FTIR), ultra violet spectrophotometry (UV), gas chromatography coupled with mass spectrometry (GC/MS), nuclear magnetic resonance
(NMR) and X-ray powder diffraction (XRPD) were used. Several of them were also used to show the stability of the drug during
various storage conditions.
DSC, FTIR and UV were used as screening techniques for assessing the compatibility of BG 637 with several commonly used pharmaceutical
excipients. We compared the properties of the pure drug with those of binary mixture drug/excipient. Studied excipients were
lactose monohydrate, microcrystalline cellulose, polyvinylpyrrolidone, sodium croscarmellose and magnesium stearate. Melting
temperature and enthalpy of BG 637 in binary mixtures were similar to theoretical values. These results showed that BG 637
is a very stable compound and compatible with several pharmaceutical excipients.
The glass transition of lyophilized materials is normally measured by conventional or temperature modulated differential scanning
calorimetry (TMDSC). However, because of the weakness of these transitions when protein concentrations are high, these techniques
are often unable to detect the glass transition (Tg). High ramp rate DSC, where heating rates of 100 K per min and higher are used, has been shown to be able to detect weak
transitions in a wide range of materials and has been applied to these materials in previous work. Dynamic mechanical analysis
(DMA) is also known to be much more sensitive to the presence of relaxations in materials than other commonly used thermal
techniques. The development of a method to handle powders in the DMA makes it now possible to apply this technique to protein
and protein-excipient mixtures. HRR DSC, TMA and DMA were used to characterize the glass transition of lyophilized materials
and the results correlated. DMA is shown to be a viable alternative to HRR DSC and TMA for lyophilized materials.
during the development of solid dosage forms, large scale development trials are normally preceded by the assessment of possible interactions between a drug and different excipients used in the formulation [ 2 , 3 ]. Although, excipients are required to
-degenerative diseases like Alzheimer’s disease could potentially be treated with Cox-2 inhibitors [ 5 ].
Studies of drug–excipient compatibility represent an important phase in the preformulation stage for the development of all dosage forms. In fact potential
morphologies, as well as many others where the presence of a particular morphology could be detrimental to the formulation.
In previous studies, methods employed to determine the extent of crystallinity of APIs and excipients included the use of
preformulation tool in predicting the eutectic compositions of various drugs and excipients at their preliminary stages of formulation.
From the results, provided in the tables, it is clear that a good correlation
In the design of quality drug products, excipients and polymers play an important role. Excipients are the chemical substances which affect the functionality, stability and drug release behaviour. Excipients are