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Even though there are reported methods for the quantification of free amino acids (FAAs) in biological products, no work has been done on the analysis of these substances in formulations. Moreover, further research is required as the reported methods do not fulfill analytical method requirements. The objective of this study was, therefore, to develop and validate a rapid, reliable, and appropriate RP-HPLC/DAD method for the simultaneous determination of 18 FAAs (l-Ala, l-Arg, l-Asn, l-Asp, l-Gln, l-Glu, l-Gly, l-His, l-Ile, l-Lue, l-Lys, l-Met, l-Orn, l-Phe, l-Pro, l-Ser, l-Thr, and l-Val) in topical formulations. After appropriate method development, the technique was validated for selectivity, linearity and range, limit of detection, limit of quantification, precision, and accuracy. The samples were derivatized with 9-fluorenylmethyl chloroformate (Fmoc-Cl). Chromatographic separation was performed on InfinityLab Poroshell 120 E.C 18 (3 × 50) mm, 2.7 μm column at 25 °C. The mobile phase consisting of water and acetonitrile adjusted to appropriate pH was pumped in gradient mode at a flow rate of 0.7 mL/min. Ten microliters were injected and analyte detection was conducted using a DAD. The results indicate that the method was selective for these FAAs. It was linear over the concentration range of 5–80 µM with a correlation coefficient greater than 0.995. Moreover, it was sensitive, precise, accurate, and robust. All the reported drawbacks of RP-HPLC-based analysis of FAAs were resolved, and hence, this new method can be considered appropriate for the analysis of these FAAs in topical formulations.

Cellulose, the most abundant biomass material in nature finds wide applications in the pharmaceutical industry. Sugarcane bagasse (SCB) is one of the main agricultural lignocellulose byproducts. The objective of this study was to prepare and characterize native and microcrystalline cellulose (MCC) from SCB and evaluate the MCC as a directly compressible pharmaceutical excipient. Cellulose was extracted from SCB by chlorine-free methods with or without dewaxing. MCC was prepared from the cellulose by hydrolysis using hydrochloric acid, and subsequently oven-dried (OD) or spray-dried (SD). The as-obtained cellulose and MCC were characterized in terms of yield, degree of polymerization (DP), chemical functionality, crystallinity, morphology and thermal stability. The chemical composition, particle size, densities and direct compressibility of MCCs were also determined. Cellulose yields on a dry weight basis were found to be 42.8 ± 1.10% and 43.5 ± 0.5% from non-dewaxed and dewaxed SCB, respectively. Dewaxed SCB cellulose (DSCBC) provided higher yield of MCC (DSCB-MCCOD, 83 ± 0.74%) than non-dewaxed SCB cellulose (SCBC) (SCB-MCCOD; 78 ± 1.07%). The DP of SCBC and DSCBC were 580.56 and 592.75, respectively, while the DP of MCC ranged from 230.10 - 251.40. The FTIR spectra of both cellulose and MCC were similar with that of Avicel PH-101. The degree of crystallinity of the dewaxed cellulose (77.34%) and MCCOD (79.56%) and MCC-SD (81.87%) were higher than non-dewaxed cellulose (74.50%) and MCC-OD (78.11%) and MCC-SD (79.62%). Scanning electron micrographs (SEM) showed a fibrous structure for DSCBC and rod-shaped for DSCB-MCC. Thermogravimetric analysis (TGA) revealed dewaxed products exhibited better thermal stability than non-dewaxed products. All MCC samples exhibited monomodal normal particle size distributions. The Hausner ratio and Carr’s index of DSCB-MCCOD and Avicel PH-101 were not significantly different (p < 0.05) indicating similar flow property and compressibility of the materials, respectively. Also, plain tablets prepared from SCB-MCC showed reasonably high crushing strengths (MCC-SD > MCC-OD), although tablets of Avicel PH-101 showed the highest crushing strengths. Thus, SCB could be an alternative source of cellulose and MCC for pharmaceutical applications.

Hydroalcoholic extracts of four different plant species [Artimesia absinthum L. (Asteraceae), Asparagusafricanus Lam. (Liliaceae), Datura stramonium L. (Solanaceae) and Nigella sativa L. (Ranunculaceae)]commonly used in traditional medicine in Ethiopia for the treatment of skin disorders were evaluated fortheir potential antimicrobial activities against pathogenic bacteria (Escherhia coli, Pseudomonas aeruginosa,Staphylococcus aureus, and Streptococcus pyogenes) and fungi (Candida albicans, Epidermophyton floccosum,Microsporum canis, Trichophyton verrucosum, and Trichophyton violaceum) using agar diffusion method. Allthe extracts showed antibacterial activities against one or more test organisms. The extract of N. sativa seedsexhibited the highest antibacterial activity against all the bacterial species tested. The minimum inhibitoryconcentrations (MICs) of the methanolic extract of N. sativa seeds were 0.156 and 2.5 mg/ml on standardstrains of S. aureus and C. albicans, respectively. Successive extraction of the seeds of N. sativa withpetroleum ether, chloroform, acetone and methanol revealed that the chloroform extract exhibited largerdiameter of zone of inhibitions against the test organisms. Phytochemical screening of the total extract of N.sativa powdered seeds revealed the presence of flavonoids, polyphenols, terpenoids, and steroids which arethought to be responsible for the activity of the extracts of N. sativa seeds. Of the various, topicalformulations of the crude extract of N. sativa seeds, the O/W emulsion based formulation showed largerdiameter of zone of inhibition. In mice paw oedema induced by carrageenan, the crude extract of N. sativa ata dose of 300 mg/kg showed the strongest anti-inflammatory activity (64.2%) followed by A. Africanus(50.1%). Keywords: skin disorders, plant extracts, antimicrobial activity, anti-inflammatory activity, minimum inhibitoryconcentration