Correction: Shakir et al. Exorbitant Drug Loading of Metformin and Sitagliptin in Mucoadhesive Buccal Tablet: In Vitro and In Vivo Characterization in Healthy Volunteers. Pharmaceuticals 2022, 15, 686.

In the original publication, a mistake was observed in Figure 5 as published [...].

Exorbitant Drug Loading of Metformin and Sitagliptin in Mucoadhesive Buccal Tablet: In Vitro and In Vivo Characterization in Healthy Volunteers.

The aim of the proposed study is to develop a mucoadhesive buccal delivery system for the sustained delivery of metformin (MET) and sitagliptin (SIT) against diabetes mellitus (DM) with improved bioavailability. Polymeric blend of Carbopol® 940 (CP), agarose (AG) or polyvinylpyrrolidone K30 (PVP) as mucoadhesive agents in formulations (R1-R15) were compressed via the direct compression technique. Tablets were characterized for solid state studies, physicochemical and in vivo mucoadhesion studies in healthy volunteers. Outcomes did not reveal any unusual peak or interaction between the drugs and polymers in the physical mixture through Fourier Transform Infrared Spectroscopy (FTIR) and DSC analysis. The mucoadhesive blend of CP and PVP was superior compared to other blends. The formulation R4 revealed exorbitant loading of drugs with complete drug release for 6 h with ex vivo mucoadhesive strength and time of 26.99 g and 8.1 h, respectively. It was further scrutinized to evaluate it as an optimized formulation where it was found to be stable for up to 6 months. The formulation R4 depicted Korsmeyer-Peppas model and first-order mode of release correspondingly for SIT and MET. Moreover, it showed hemocompatibility, biocompatibility and stability with non-significant changes in the dissolution profile. Overall, the CP blend with PVP was found appropriate to yield the desired release coupled with the optimized mucoadhesive properties of the buccal tablets, ensuring sufficient pharmaceutical stability.

Validation of a rapid and economical RP-HPLC method for simultaneous determination of metformin hydrochloride and sitagliptin phosphate monohydrate: Greenness evaluation using AGREE score.

Reported high performance liquid chromatographic (HPLC) methods for estimating metformin hydrochloride (MET) and sitagliptin phosphate monohydrate (SIT) are either laborious or contain higher proportions of organic solvents in mobile phase, thus presenting exorbitant procedures. So, a rapid, significantly more economical and eco-friendly HPLC method for synchronized analysis of both drugs was aimed to develop and validate in current study. Analytical evaluation was executed on Shimadzou⌖ C18 column (250mm × 4.6mm, 5µm) using acidified water and methanol 60:40 (v/v) as mobile phase at a flow of 1mL/min; while peaks were detected at 260nm at 25°C. Resultant values of accuracy, precision, linearity, limit of detection (LOD), limit of quantification (LOQ), robustness and specificity depicted that the method was validated in accordance with the ICH Guidelines. The approximate retention time for MET and SIT were 1.96 and 3.70 min, correspondingly. The greenness score of the developed method was evaluated using AGREE software and was found better (0.81) as compared with the methods reported (<0.8). Conclusively, the developed method was time saving, economical, rapid, robust, rugged, precise, accurate and found to be applicable for simultaneous determination of MET and SIT in commercial tablets.

Optimization of metronidazole SR buccal tablet for gingivitis using genetic algorithm.

Gingivitis is a condition that needs sustained concentration of antibiotic locally over extended period of time. The current study aimed to formulate and evaluate the sustained and localized release of metronidazole (MTZ) as mucoadhesive buccal tablet containing hydroxypropylmethyl cellulose (HPMC), Carbopol 940® (CP), carboxymethylcellulose (CMC) and ethyl cellulose (EC) as mucoadhesive polymers. Tablets were directly compressed with proportions of polymeric blends (F1-F16). The results indicated that weight variation (249±2.10mg) and friability (0.21%) were within USP compendial limits. Maximum mucoadhesive strength and time were depicted by F1 and F14 which were 28.47g and 12hr respectively. Formulations, except F4, were within physiological pH limit. Maximum swellability index (261.9%) was exhibited by F16, at 8 hr, containing highest concentration of CP, HPMC and additional CMC. For in vitro release, the pre-set 8 hr complete release were shown by formulations, F15 and F16 which were 100% and 97%, respectively. Genetic algorithm was applied on the attributes to optimize polymeric response in accordance with desirability. The software predicted composition (F17) was tested which revealed that physical characteristics were in accordance with the compendial standards. The release kinetics, evaluated through DDsolver⌖, suggested that release of MTZ followed non-Fickian diffusion type in Korsmeyer-Peppas model. Therefore, MTZ, if delivered as mucoadhesive buccal formulation (F17) containing amounts (mg) of CP (16.4), HPMC (78.7), CMC (8.3) and EC (10.5) will simulate satisfactory release i.e. 96% at 8 hr in simulated buccal fluid.