Spectrum subtraction as a complementary method for six resolution techniques resolving overlapping spectra; application to multicomponent veterinary formulation with greenness and whiteness assessment.

Mathematical filtration is an efficient tool to resolve the overlapping spectra of binary mixtures in zero or first order form. Herein, a comparative study was conducted between six economic, accurate and precise spectrophotometric methods for determination of Triclabendazole (TCB) and Levamisole HCl (LVM). Each component was resolved with minimum mathematical steps in its zero-order absorption spectrum by ratio subtraction, constant multiplication, and the recent factorized response method; coupled with spectrum subtraction. In addition, the mixture was resolved in its first derivative form by derivative subtraction, D1 constant multiplication, and the recent D1 factorized response method; coupled with spectrum subtraction. Results obtained were also compared to those obtained from constant value, concentration value, and derivative ratio methods. The linearity range was found to be either 1.0-10.0 µg/mL or 2.0-20.0 µg/mL for TCB, and 2.0-14.0 µg/mL for LVM with LOD of 0.08 µg/mL and 0.19 µg/mL, respectively. Validation of the proposed methods was performed according to VICH guidelines. Results obtained from the statistical data showed no significant difference regarding accuracy and precision compared to the reported methods. The developed spectrophotometric methods followed the principles of green analytical chemistry, in which the green assessment was done through four tools, called, National Environmental Methods Index (NEMI), Analytical Eco-Scale (AES), Green Analytical Procedure Index (GAPI) and Analytical greenness metric (AGREE). Also, a white assessment was performed using RGB model. The proposed methods could offer an economic alternative for the routine analysis of bulk materials and combined veterinary dosage form.

Evaluation of functional and aesthetic outcomes of free dermal fat graft versus superficial musculoaponeurotic system flap after superficial parotidectomy: randomized clinical trial.

BACKGROUND: Parotidectomy is the standard procedure for treatment of many parotid lesions; however, it has several drawbacks. Facial asymmetry and Frey's syndrome are the most annoying complications to patients. Insertion of interpositioning grafts into the parotidectomy bed can decrease these complications significantly. Free dermal fat graft (FDFG) and superficial musculoaponeurotic system (SMAS) flap have very promising results. This RCT aimed to compare these two techniques regarding functional and aesthetic outcomes. METHODS: Between February 2016 and October 2021, adult patients undergoing superficial conservative parotidectomy in a single centre for a benign indication were randomized into two equal groups using a closed envelope method. In one group, FDFG was inserted at the parotidectomy bed, whereas, in the other group, SMAS flap was performed. Preoperative, operative, and postoperative data were recorded and analysed. The primary outcome was the development of Frey's syndrome. RESULTS: Seventy-eight patients were randomized into two equal groups of 39 patients. There was no significant difference between the two groups regarding development of Frey's syndrome. There was no significant statistical difference between study groups regarding demographic data, co-morbidities, parotid pathologies, specimen volumes, total operating time, and postoperative complications. A tendency for over correction was observed in FDFG and under correction in SMAS flap. There was no statistically significant difference between the study groups regarding the patients' aesthetic satisfaction with the majority displaying excellent satisfaction with no poor results. CONCLUSION: FDFG and SMAS flap are simple, rapid, and reliable procedures and are effective in improving both functional and aesthetic outcomes post-parotidectomy. They have comparable results; however, selection of either procedure can be determined according to patient and tumour characteristics. Registration number: NCT05452837 (http://www.clinicaltrials.gov).

Novel eco-friendly spectrophotometric approaches for resolution of fixed dose formulation of phenylbutazone with minor component of dexamethasone: Greenness assessment by AGREE tool.

Spectrophotometric resolution of severely overlapped binary mixtures with minor component is challenging. Herein, coupling of mathematical manipulation steps with sample enrichment was conducted on the binary mixture spectrum of Phenylbutazone (PBZ) and Dexamethasone sodium phosphate (DEX) to resolve, for the first time each component separately. Simultaneous determination of both components in a mixture ratio of 1:0.002 was achieved in their zero or first order spectra by the recent factorized response method along with ratio subtraction and constant multiplication methods; all coupled with spectrum subtraction. In addition, a novel second derivative concentration value and second derivative constant value methods were developed for PBZ determination. The concentration of the minor component DEX was obtained, without preliminary separation steps by derivative ratio after sample enrichment by either spectrum addition or standard addition. Spectrum addition approach showed superior characteristics compared to standard addition technique. All proposed methods were placed through a comparative study. Linear correlation was found to be 1.5-18.0 µg/mL for PBZ, and 4.0-45.0 µg/mL for DEX. The proposed methods were validated in accordance with ICH guidelines. The greenness assessment of the proposed spectrophotometric methods was evaluated by AGREE software. Results obtained from the statistical data were evaluated by comparing to one another as well as the official USP methods. These methods offer a cost and time effective platform to analyze bulk materials and combined veterinary formulation.