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Background: Cocrystals are defined as multiple component structures whose components interact through non-covalent interactions.Cocrystals can enhance other essential properties of the APIs.Aim: The current research work focuses on formulating and evaluating novel co-crystals of Lamotrigine anti-epileptic drug (BCS-II)Methods: The Cocrystals of Lamotrigine drug with different cocrystals formers like Saccharin sodium, 4-Hydroxy benzoic acid, andMethyl paraben used with molar ratios (1:1) were prepared by solvent drop method, co-grinding method, and solvent evaporationmethod.Results: The results signify the establishment of intermolecular interaction within the cocrystals. In the novel cocrystals, Lamotriginewas determined to be engaged in the hydrogen bond interaction with the complementary functional groups of Saccharin sodium, 4-Hydroxy benzoic acid, and methyl paraben. Compared with the pure Lamotrigine flow properties for prepared co-crystal by usingsolvent evaporation method crystals are showing excellent flow properties. LTG-SAC CF I, LTG-HBA I, and LTG-MP III showed49.6 folds, 7.4 folds, and 3.36 folds improved solubility respectively. The dissolution test showed that the LTG-SAC CF I, LTG-HBAI, and LTG-MP III cocrystals exhibited a 1.09-fold, 1.08-fold, and 1.07-fold higher dissolution rate than the pure Lamotrigine.Conclusions: LTG-SAC CF I, LTG-HBA I, and LTG-MP III cocrystals showed modification in the chemical environment,intermolecular interactions were established, improved flow properties with enhanced intrinsic solubility and in-vitro dissolution ratethan pure drug.

Objective: The objective of this work is to develop a precise, accurate and validated reverse phase ultra-performance liquid chromatographic technique for effective simultaneous determination of Emtricitabine, Tenofovir and Efavirenz in bulk and tablet formulation. Method: Separation of the selected drugs was optimized after several trials including changing mobile phase and its composition, stationary phase, flow rate, column temperature, etc. Finally the separation of drugs was achieved on BEH C18 column using a mixture of methanol and phosphate buffer having pH 3.5 in the ratio of 65:35 v/v as mobile phase with flow rate of 0.3 ml/min and the analytes were detected at a wavelength of 260 nm. Results: The developed method was validated by determining the parameters like linearity, system suitability, recovery, precision, specificity, robustness, ruggedness, LOD, and LOQ as per the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH) guidelines. The system suitability parameters were within the limits, retention times (Rt) for Emtricitabine, Tenofovir and Efavirenz were found to be 0.432, 0.671, and 2.772 min respectively. The method showed linearity between the concentration range of 10-50 μg/ml for Emtricitabine (r2= 0.9987), 15-75 μg/ml for Tenofovir (r2= 0.9983) and 30-150 μg/ml for Efavirenz (r2= 0.9982). The percentage recovery results at 50%, 100% and 150% of Emtricitabine, Tenofovir and Efavirenz were found to be in the range of 99.45 % - 100.15 %. Since there was no interference due to excipients and mobile phase, the method was found to be specific. The assay results of the combined tablet dosage form by the developed method were identified as in good agreement with the acceptance limit. Conclusions: The current method was proved to be effective for routine simultaneous determination of Emtricitabine, Tenofovir and Efavirenz in bulk and tablet formulation.

Since the stability of the pharmaceuticals plays a crucial role in efficacy and safety while using them in the treatment of disorders, the evaluation of purity and impurity profiling of pharmaceuticals is of utmost importance using efficient analytical techniques. The present study explains the identification, isolation, and characterization of stress degradation products of the anti-human immunovirus drug Darunavir. The degradation study was performed to evaluate the stability profile of Darunavir in different stress conditions like hydrolytic, oxidative, thermal, and photolytic conditions as per the ICH guidelines. Degradation products were identified using ultra-performance liquid chromatography coupled with mass spectrometry, isolated using semi-preparative high-performance liquid chromatography, and structural characterization by HRMS and 1 H, 13 C NMR (1D, 2D). Darunavir is relatively stable in oxidative, thermal, and photolytic conditions; however, considerable degradation was observed in acid and base hydrolysis. A total of five degradation products were identified and isolated in acid and base degradation. DP-1, DP -2, & DP-3 were observed in acid conditions, whereas in base conditions, along with DP-2, two more DPs, i.e., DP-4 & DP-5, were identified. Among the five DPs, two degradation products, namely DP-1 : N-(4-(N-(3-amino-2-hydroxy-4-phenylbutyl)-N-isobutylsulfamoyl) phenyl) acetimidamide. & DP-3 : hexahydrofuro[2,3-b]furan-3-yl(4-((4-acetimidamido-N-isobutylphenyl)sulfonamido)-3-hydroxy-1-phenylbutan-2-yl)carbamate, are novel, remaining degradation products DP-2: 4-amino-N-(3-amino-2-hydroxy-4-phenylbutyl)-N-isobutylbenzenesulfonamide, DP-4 : 4-amino-N-(((5S)-4-benzyl-2-oxooxazolidin-5-yl) methyl) -N-isobutyl benzenesulfonamide and DP-5 : methyl ((3S)-4-((4-amino-N-isobutylphenyl) sulfonamido)-3-hydroxy-1-phenylbutan-2-yl) carbamate are already reported tentatively using a single analytical technique coupled with mass analysis without any evidence from NMR and IR data. Hence, the present study focused on using High-Resolution Mass, 1D, and 2D 1 H, 13 C NMR data for concrete confirmation of structures for degradation products. Supplementary Information The online version contains supplementary material available at 10.1007/s10337-022-04226-z.