Polymorphism: an evaluation of the potential risk to the quality of drug products from the Farmácia Popular Rede Própria

Polymorphism in solids is a common phenomenon in drugs, which can lead to compromised quality due to changes in their physicochemical properties, particularly solubility, and, therefore, reduce bioavailability. Herein, a bibliographic survey was performed based on key issues and studies related to polymorphism in active pharmaceutical ingredient (APIs) present in medications from the Farmácia Popular Rede Própria. Polymorphism must be controlled to prevent possible ineffective therapy and/or improper dosage. Few mandatory tests for the identification and control of polymorphism in medications are currently available, which can result in serious public health concerns

Relationships between structural and thermal properties of anhydrous and solvated crystalline forms of brodimoprim

The isolation and physicochemical characterization of four crystalline modifications of brodimoprim (5-[(4-bromo-3,5-dimethoxyphenyl)methyl]-2,4-pyrimidinediamine, hereinafter BMP), a structural analog of trimethoprim (TMP), are reported. These phases include an unsolvated form of BMP, a hemihydrate (BMP0.5H2O), a 1:1 solvate containing isopropanol (BMPC3H7OH(iso)), and a hemichloroformate (BMP0.5CHCl3). Unsolvated BMP was isolated both by recrystallization from a range of common solvents as well as by thermal decomposition of the above solvates and no evidence for polymorphism was found. PXRD data indicated that the three solvates crystallize in different arrangements. Data from thermal analysis (thermogravimetry (TGA), hot stage microscopy (HSM), differential scanning calorimetry (DSC)) of the solvates containing water and iso-propanol were interpreted on the basis of their singlecrystal X-ray structures which revealed that the modes of solvent inclusion in BMP0.5H2O and BMPC3H7OH(iso) may be described as ‘isolated site’ and ‘lattice channel’ type inclusions, respectively

Crystal form conversion of nevirapine solvates subjected to elevated temperature and humidity: a qualitative study

Some known nevirapine solvates have been reported to undergo solvent exchange in aqueous media to form a stable hemihydrate. This study aimed to determine the effects of atmospheric moisture on said nevirapine solvates and to gain insight into which factors determine the end product of transformation. Solvates were prepared by solvent recrystallisation and stored, together with the anhydrous and hemihydrate forms, in a climate chamber at 40 °C and 75% RH for a period of 28 days. Samples were analyzed using DSC, TGA, FT-IR, PXRD and Karl Fischer titration. Some solvates were observed to undergo desolvation to the anhydrous form of nevirapine (Form I), whilst others converted to the hemihydrate. It was found that water miscibility of the guest solvent determined the stable form of nevirapine, anhydrous or hemihydrate, to which each solvate eventually transformed. Transformation to the hemihydrate only occurred if the guest solvent was sufficiently water soluble to allow water molecules to enter solvent channels and displace the original guest. Solvates with hydrophobic guests desolvated to the anhydrous form. We concluded that, in the absence of a guest, solvent channels are lost during transformation to the monoclinic crystal system and space group P21/c (Form I) so that water cannot enter after desolvatio