Assessment of Residual Solvent and Drug in PLGA Microspheres by Derivative Thermogravimetry

Abstract

<jats:p>Thermogravimetry does not give specific information on residual organic solvents in polymeric matrices unless it is hyphenated with the so-called evolved gas analysis. The purpose of this study was to apply, for the first time, derivative thermogravimetry (DTG) to characterize a residual solvent and a drug in poly-d,l-lactide-co-glycolide (PLGA) microspheres. Ethyl formate, an ICH class 3 solvent, was used to encapsulate progesterone into microspheres. DTG provided a distinct peak, displaying the onset and end temperatures at which ethyl formate started to evolve from to where it completely escaped out of the microspheres. DTG also gave the area and height of the solvent peak, as well as the temperature of the highest mass change rate of the microspheres. These derivative parameters allowed for the measurement of the amount of residual ethyl formate in the microspheres. Interestingly, progesterone affected not only the residual solvent amount but also these derivative parameters. Another intriguing finding was that there was a linear relationship between progesterone content and the peak height of ethyl formate. The residual solvent data calculated by DTG were quite comparable to those measured by gas chromatography. In summary, DTG could be an efficient and practical quality control tool to evaluate residual solvents and drugs in various polymeric matrices.</jats:p>

Synthesis of novel coumarin-triazole hybrids and first evaluation of the 4-phenyl substituted hybrid loaded PLGA nanoparticles delivery system to the anticancer activity

“…The same result is well described in the literature [58]. TGA is also used to identify weight loss because of the volatilization of residual solvents in nanoparticles that take place around the boiling point of it [59]. Curiously, when both empty and 21loaded PLGA nanoparticles were analyzed by TGA, no considerable weight loss was monitored at the boiling point of DCM at 40 °C approving its absence as residual solvent.…”

A Film of Chitosan Blended with Ginseng Residue Polysaccharides as an Antioxidant Packaging for Prolonging the Shelf Life of Fresh-Cut Melon

“…Figure 3B presents the second derivative of the data shown in Figure 3A, which can more intuitively reflect which temperature has the maximum weight loss rate. The reversed peaks of the derivative thermogravimetry correspond to the maximum change rate of weight loss [26]. As shown in Figure 3B, for both CF, CF + L-GRP, and CF + H-GRP, there is only one reversed peak in the first stage, but two in the second stage.…”

Applications of capillary action in drug delivery

“…However, due to the weak interaction between hydrophilic molecules and hydrophobic carriers, the encapsulation efficiency of hydrophilic and/or amphiphilic small molecules is unsatisfactory (Li et al, 2020). In addition, this method involves using organic solvents in the manufacturing process, leading to solvent residue problems in the formulation (Sah and Sah, 2015;Shim and Sah, 2020).…”