The objective of this study was to evaluate the effect of sonication time and pulse frequency on average dispersion temperature (ART), particle size and zeta potential of solid lipid nanoparticles (SLNs). A two-factor, three-level response surface methodology (RSM) was used to optimize sonication time between 5 and 15 min and pulse frequency from 30 to 90%. SLNs made from stearyl alcohol (SA) and cetyl trimethylammonium bromide (CTAB) blend at 1:3 ratio were prepared by applying high-shear homogenization and sonication. Pulse frequency and time were found to have a significant effect on particle size and ART. The effect of sonication parameters on zeta potential, however, was insignificant. The optimal sonication parameters for preparing 100 nm SLNs made from a SA/CTAB blend was 60% pulse frequency at 40% power for 10 min. Optimized sonication parameters were then used to investigate the effect of lipid type on SLN size and zeta potential. The mean particle sizes of SLNs made with SA, cetyl palmitate, Precirol®, Dynasan118® and Compritol® were 98, 190, 350, 350 and 280 nm, respectively. In conclusion, pulse frequency and time were found to be critical for obtaining SLNs with desirable size, whereas the stability of the SLNs was dependent on their lipid content.

No abstract

The objective of the present study was to develop a tablet formulation with a zero-order drug release profile based on a balanced blend of three matrix ingredients. To accomplish this goal, a 17-run, three-factor, two-level D-Optimal mixture design was employed to evaluate the effect of Polyox (X1), Carbopol (X2), and lactose (X3) concentrations on the release rate of theophylline from the matrices. Tablets were prepared by direct compression and were subjected to an in vitro dissolution study in phosphate buffer at pH 7.2. Polynomial models were generated for the responses Y4 (percent released in 8 h) and Y6 (similarity factor or f2). Fitted models were used to predict the composition of a formulation that would have a similar dissolution profile to an ideal zero-order release at a rate of 8.33% per hour. When tested, dissolution profile of the optimized formulation was comparable to the reference profile (f2 was 74.2, and n [release exponent] was 0.9). This study demonstrated that a balanced blend of matrix ingredients could be used to attain a zero-order release profile. Optimization was feasible by the application of response surface methodology, which proved efficient in designing controlled-release dosage forms.

Cancer is a life threatening malignant tumor, caused by many factors including the oxidative stress. Medicinal plants containing phenolic compounds represent an important source of antioxidant and anticancer drugs. Azadirachta indica Family: Meliaceae contains variety of bioactive components of numerous biological and pharmacological properties. This study explored the constitutive polyphenols of Azadirachta indica (A. indica) growing in KSA and evaluated its antioxidant and cytotoxic activity. Chemical structures of the isolated compounds from the leaves of A. indica were established by spectral techniques (UV, MS, 1H, and 13 C NMR, and two dimentional NMR). The colourimetric assay (SRB) used to evaluate the cytotoxicity against HCT 116 , MCF 7 and Hep-G 2 cell lines. Chromatographic separation of 80% Ethanol extract of the leaves of A. indica have resulted in seven polyphenolic compounds three of them isolated for the first time from this species (2,3-(S)-hexahydroxydiphenoyl-(α α α α α/β β β β β)-D-glucopyranose, Avicularin and Castalagin) and four known previously isolated compounds (Gallic acid, Ellagic acid, Quercetin and Quercetin-3-O-glucoside). The 80% Ethanol extract exhibited higher antioxidant activity than the ethyl acetate and butanol extracts, which is correlated with its phenolic content. The ethanolic extract, compounds 4 and 6 exhibited cytotoxic activity against HCT 116 , MCF 7 and Hep-G 2. These findings revealed that the leaves of A. indica contains a considerable amount of polyphenolic compounds with significant antioxidant and cytotoxic activity, consequently it could be considered as a great potential source for natural health products.