The objective of this work was to evaluate liposome-containing gel formulations for the sustained, site-specific delivery of celecoxib (CXB). Liposomes composed of phosphadtidylcholine (and various amounts of cholesterol (Ch) were prepared using thin film hydration and characterized for encapsulation efficiency, vesicle size, and drug-excipient interaction using differential scanning calorimetry and Fourier-transform infrared spectroscopy. The selected liposome formulation was incorporated in different gel formulations: the Ch ratio affected the encapsulation efficiency of the drug, by increasing Ch ratio up until 1:1 the encapsulation efficiency increased. Further increasing the Ch ratio resulted in decreasing encapsulation efficiency. In vitro drug release and skin permeation studies showed sustained release and enhanced permeation compared with gel formulations containing free drug. In the rat paw edema test, the anti-inflammatory activity of the selected liposomal gel formulation was higher and more sustained compared with that of the nonliposomal gel formulation containing free drug. These results suggest that the liposome-containing gels are promising formulations for sustained, site-specific delivery of CXB.

Ionotropic gelation method was used to entrap Ketoprofen (KP) into calcium alginate beads. KP is one of the non steroidal anti-inflammatory drugs (NSAIDs); it has a short half life (1.5-2 h) and deleterious side effects on GIT such as irritation and ulceration. Beads were investigated in-vitro for possible sustained drug release and in-vivo as a gastro-protective system for KP. The curing time of beads in CaCl2 solution was determined and process variables, such as polymer concentration, polymer/drug ratio and co-entrapped polymers (Gelatin (G), Hydroxy propyl methyl cellulose acetate succinate (HPMCAS) and ethyl cellulose (EC)) were analyzed for their influence on bead properties. On the basis of differential scanning colorimetry (DSC) and IR- spectroscopy, alginate was found to be compatible with KP. Scanning electron microscopy (SEM) photographs showed that the prepared beads were spherical and small (about 1 mm diameter) with small cracks and fissures on the surface. KP encapsulation efficiencies were high (>90%), also results showed that, release profile in 0.1M HCl (pH 1) was slow. while in phosphate buffer (pH 7.4), complete drug release was exhibited for all formulations within 2 h. There was no improvement concerning the retarding of drug release with co-entrapped polymers. The mechanism of release was depending on swelling and erosion of beads. The swelling behavior was strongly dependent on pH of the medium; such a pH sensitive swelling could be advantageous for orally administered drug vehicles especially for acid sensitive drugs or drugs that have adverse effects on GIT. The Ulcerogenic effect of the free drug on the stomach was compared to that of drug encapsulated in alginate beads using rats. Results showed a significant mucoprotective effect of alginate beads compared to the free drug. In conclusion, alginate beads can be used as enteric coated formulations rather than ideal sustained release formulations.

Ionotropic gelation method was used to entrap Ketoprofen (KP) into calcium alginate beads. KP is one of the non steroidal anti-inflammatory drugs (NSAIDs); it has a short half life (1.5-2 h) and deleterious side effects on GIT such as irritation and ulceration. Beads were investigated in-vitro for possible sustained drug release and in-vivo as a gastro-protective system for KP. The curing time of beads in CaCl2 solution was determined and process variables, such as polymer concentration, polymer/drug ratio and co-entrapped polymers (Gelatin (G), Hydroxy propyl methyl cellulose acetate succinate (HPMCAS) and ethyl cellulose (EC)) were analyzed for their influence on bead properties. On the basis of differential scanning colorimetry (DSC) and IR- spectroscopy, alginate was found to be compatible with KP. Scanning electron microscopy (SEM) photographs showed that the prepared beads were spherical and small (about 1 mm diameter) with small cracks and fissures on the surface. KP encapsulation efficiencies were high (>90%), also results showed that, release profile in 0.1M HCl (pH 1) was slow. while in phosphate buffer (pH 7.4), complete drug release was exhibited for all formulations within 2 h. There was no improvement concerning the retarding of drug release with co-entrapped polymers. The mechanism of release was depending on swelling and erosion of beads. The swelling behavior was strongly dependent on pH of the medium; such a pH sensitive swelling could be advantageous for orally administered drug vehicles especially for acid sensitive drugs or drugs that have adverse effects on GIT. The Ulcerogenic effect of the free drug on the stomach was compared to that of drug encapsulated in alginate beads using rats. Results showed a significant mucoprotective effect of alginate beads compared to the free drug. In conclusion, alginate beads can be used as enteric coated formulations rather than ideal sustained release formulations.

Ionotropic gelation method was used to entrap Ketoprofen (KP) into calcium alginate beads. KP is one of the non steroidal anti-inflammatory drugs (NSAIDs); it has a short half life (1.5-2 h) and deleterious side effects on GIT such as irritation and ulceration. Beads were investigated in-vitro for possible sustained drug release and in-vivo as a gastro-protective system for KP. The curing time of beads in CaCl2 solution was determined and process variables, such as polymer concentration, polymer/drug ratio and co-entrapped polymers (Gelatin (G), Hydroxy propyl methyl cellulose acetate succinate (HPMCAS) and ethyl cellulose (EC)) were analyzed for their influence on bead properties. On the basis of differential scanning colorimetry (DSC) and IR- spectroscopy, alginate was found to be compatible with KP. Scanning electron microscopy (SEM) photographs showed that the prepared beads were spherical and small (about 1 mm diameter) with small cracks and fissures on the surface. KP encapsulation efficiencies were high (>90%), also results showed that, release profile in 0.1M HCl (pH 1) was slow. while in phosphate buffer (pH 7.4), complete drug release was exhibited for all formulations within 2 h. There was no improvement concerning the retarding of drug release with co-entrapped polymers. The mechanism of release was depending on swelling and erosion of beads. The swelling behavior was strongly dependent on pH of the medium; such a pH sensitive swelling could be advantageous for orally administered drug vehicles especially for acid sensitive drugs or drugs that have adverse effects on GIT. The Ulcerogenic effect of the free drug on the stomach was compared to that of drug encapsulated in alginate beads using rats. Results showed a significant mucoprotective effect of alginate beads compared to the free drug. In conclusion, alginate beads can be used as enteric coated formulations rather than ideal sustained release formulations.

Ionotropic gelation method was used to entrap Ketoprofen (KP) into calcium alginate beads. KP is one of the non steroidal anti-inflammatory drugs (NSAIDs); it has a short half life (1.5-2 h) and deleterious side effects on GIT such as irritation and ulceration. Beads were investigated in-vitro for possible sustained drug release and in-vivo as a gastro-protective system for KP. The curing time of beads in CaCl2 solution was determined and process variables, such as polymer concentration, polymer/drug ratio and co-entrapped polymers (Gelatin (G), Hydroxy propyl methyl cellulose acetate succinate (HPMCAS) and ethyl cellulose (EC)) were analyzed for their influence on bead properties. On the basis of differential scanning colorimetry (DSC) and IR- spectroscopy, alginate was found to be compatible with KP. Scanning electron microscopy (SEM) photographs showed that the prepared beads were spherical and small (about 1 mm diameter) with small cracks and fissures on the surface. KP encapsulation efficiencies were high (>90%), also results showed that, release profile in 0.1M HCl (pH 1) was slow. while in phosphate buffer (pH 7.4), complete drug release was exhibited for all formulations within 2 h. There was no improvement concerning the retarding of drug release with co-entrapped polymers. The mechanism of release was depending on swelling and erosion of beads. The swelling behavior was strongly dependent on pH of the medium; such a pH sensitive swelling could be advantageous for orally administered drug vehicles especially for acid sensitive drugs or drugs that have adverse effects on GIT. The Ulcerogenic effect of the free drug on the stomach was compared to that of drug encapsulated in alginate beads using rats. Results showed a significant mucoprotective effect of alginate beads compared to the free drug. In conclusion, alginate beads can be used as enteric coated formulations rather than ideal sustained release formulations.

The aim of this study was to develop and evaluate self-nanoemulsifying drug delivery system (SNEDDS) of tadalafil (TDL) in order to enhance its aqueous solubility and dissolution rate. TDL SNEDDS were developed by aqueous phase titration method via construction of pseudo-ternary phase diagrams. The formulations which passed thermodynamic stability and self-nanoemulsification tests were further characterized in terms of droplet size, viscosity, % transmittance and drug content. Selected SNEDDS and drug suspension were subjected to in vitro drug release studies via dialysis membrane in phosphate buffer (pH 6.8). In vitro drug release studies showed 96.6% release of TDL from optimized SNEDDS F5 as compared to only 12.4% from drug suspension after 24 h of study. The results of solubility studies showed 1434 folds enhancement in TDL solubility from optimized SNEDDS F5 as compared to its aqueous solubility. Overall, these results indicated that developed SNEDDS could be successfully used to enhance solubility and dissolution rate of poorly soluble drugs such as TDL.

The aim of this study was to develop and evaluate self-nanoemulsifying drug delivery system (SNEDDS) of tadalafil (TDL) in order to enhance its aqueous solubility and dissolution rate. TDL SNEDDS were developed by aqueous phase titration method via construction of pseudo-ternary phase diagrams. The formulations which passed thermodynamic stability and self-nanoemulsification tests were further characterized in terms of droplet size, viscosity, % transmittance and drug content. Selected SNEDDS and drug suspension were subjected to in vitro drug release studies via dialysis membrane in phosphate buffer (pH 6.8). In vitro drug release studies showed 96.6% release of TDL from optimized SNEDDS F5 as compared to only 12.4% from drug suspension after 24 h of study. The results of solubility studies showed 1434 folds enhancement in TDL solubility from optimized SNEDDS F5 as compared to its aqueous solubility. Overall, these results indicated that developed SNEDDS could be successfully used to enhance solubility and dissolution rate of poorly soluble drugs such as TDL.

The study describes the development and validation of a new microwell-based spectrophotometric assay for determination of olmesartan medoxomil (OLM) in tablets. The formation of a colored charge-transfer (CT) complex between OLM as an n-electron donor and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) as a -electron acceptor was investigated, and employed as the basis for the development of the new assay. The proposed assay was conducted in 96-microwell plates. The absorbance of the colored-CT complex was measured at 460 nm with a microplate reader. Optimum conditions of the reaction and the analytical procedures of the assay were established. Under the optimum conditions, a linear relationship with a good correlation coefficient was found between the absorbance and the concentration of OLM in the range of 2–200 μg per well. The limits of detection and quantitation were 0.53 and 1.61 μg per well, respectively. No interference was observed from the excipients present in OLM tablets or from hydrochlorothiazide and amlodipine besylate that were co-formulated with OLM in some of its formulations. The assay was successfully applied to the analysis of OLM in tablets with good accuracy and precision. The assay described herein has a great practical value in the routine analysis of OLM in quality control laboratories, since it has a high throughput property and consumes low volumes of organic solvent. It thus offers a reduction in the exposure of analysts to the toxic effects of organic solvents, as well as a reduction in the cost of analysis.

The reaction of 1,4-benzoquinone (BQ) with crizotinib (CZT); a novel drug used for treatment of non-small cell lung cancer) was investigated in different solvents of varying dielectric constants and polarity indexes. The reaction resulted in the formation of a red-colored product. Spectrophotometric investigations confirmed that the reaction proceeded through charge-transfer (CT) complex formation. The molar absorptivity of the complex was found to be linearly correlated with the dielectric constant and polarity index of the solvent; the correlation coefficients were 0.9425 and 0.8340, respectively. The stoichiometric ratio of BQ:CZT was found to be 2:1 and the association constant of the complex was found to be 0.26 x 103 l mol1. The kinetics of the reaction was studied; the order of the reaction, rate and rate constant were determined. Computational molecular modeling for the complex between BQ and CZT was conducted, the sites of interaction on CZT molecule were determined, and the mechanism of the reaction was postulated. The reaction was employed as a basis in the development of a novel 96-microwell assay for CZT. The assay limits of detection and quantitation were 5.2 and 15.6 µg ml1, respectively. The assay was validated as per the guidelines of the International Conference on Harmonization (ICH) and successfully applied to the analysis of CZT in its bulk and capsules with good accuracy and precision. The assay has high throughput and consumes minimum volume of organic solvent thus it reduces the exposures of the analysts to the toxic effects of organic solvents, and significantly reduces the analysis cost.

Two new, sensitive, and selective spectrofluorometric methods were developed for the determination of gemifloxacin mesylate (GFX) in tablets and spiked human plasma. Method A was based on measurement of the enhanced fluorescence spectral behaviour of GFX in a sodium dodecyl sulphate (SDS) micellar system. In aqueous solution of acetate buffer pH 5.5, the fluorescence intensity of GFX was greatly enhanced about tenfold in the presence of SDS. The fluorescence intensity was measured at 402 nm after excitation at 274 nm. Method B was based on Hantzsch condensation reaction between the primary amino group of GFX with acetylacetone and formaldehyde in acetate buffer of pH 3.5 yielding a highly yellow fluorescent derivative. The reaction of GFX with acetylacetone-formaldehyde system solution resulted in bathochromic shift of both emission (476 nm) and excitation (420 nm) wavelengths. The fluorescence intensity was directly proportional to the concentration over the range 10–1000 ng/ml and 100–2000 ng/ml for method A and B, respectively. The proposed methods were applied successfully for determination of GFX in its tablets and spiked plasma. Therefore, these methods can be considered of real interest for reliable and practical quality control analysis of GFX.