Influence of particle shape on plasma protein adsorption and macrophage uptake.

The purpose of this study was to evaluate the plasma protein adsorption behavior onto different LIPOMER nanoparticles, especially looking for the first time, if the particle shape affects the protein adsorption pattern. The potential in vivo fate is discussed and compared with previous in vivo animal studies. The two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) was used for identification of adsorbed plasma proteins. Qualitative similar patterns were obtained from the protein adsorption analysis and four apolipoproteins with considerable quantitative differences were identified. Besides the quantitative differences in the adsorbed apolipoproteins, in vitro uptake in the human macrophage cell line U-937 of histocytic lymphoma organ revealed significantly lower uptake of the irregular glycerol monostearate LIPOMER nanoparticles. Therefore, protein adsorption does not seem to play a role in the splenotropic behavior in the sense, that adsorption of opsonins, especially spleen-specific opsonins are required for the uptake. The splenotropic uptake might be favored because all LIPOMER nanoparticles did not adsorb opsonins at all, mediating competitive uptake by liver macrophages. Differences in the in vivo uptake by the spleen were attributed to differences in particle shape with potential super position effect by the quantitative differences in the adsorbed proteins.

HPTLC determination of ketorolac tromethamine.

A High Performance Thin Layer Chromatography (HPTLC) method for quantification of ketorolac tromethamine, a non-narcotic and non-steroidal agent was developed. The mobile phase composition was chloroform-ethyl acetate-glacial acetic acid (3:8:0.1, v/v/v). Spectrodensitometric analysis of ketorolac tromethamine was carried out at 323 nm. The calibration curve was linear in the range of 200-700 ng. The mean values of slope, intercept and correlation coefficient were, 2941, 749583, 0.99. The method was validated for method precision, system precision, marketed sample analysis and recovery studies. The % CV for method precision studies was 1.98 (n = 6) and system precision study was 1.83 (n = 6). The average recovery was found to be 99.2%. Acid and base degraded products were adequately separated from the drug. The method was successfully used for the determination of drug from saliva. The results indicate that the method is simple, specific, selective and reliable for quantitative analysis of ketorolac tromethamine as bulk drug and from formulations. It can also be applied for the stability study of the drug and analysis of drug in biological fluids.

Simultaneous determination of lignocaine hydrochloride and phenylephrine hydrochloride by HPTLC.

A high performance thin layer chromatographic (HPTLC) method for the simultaneous quantification of lignocaine hydrochloride (LIG) and phenylephrine hydrochloride (PHE) is described. The mobile phase consisted of ethyl acetate-methanol ammonia (4:1:0.4 v/v/v). The densitometric determination of LIG and PHE was carried out at 262 nm and 291 nm, respectively. The calibration curves of LIG and PHE were linear in the range of 8-18 microg and 4-9 microg, respectively. The method was validated with respect to system precision, method precision, recoveries, intra-day and inter-day variation. The system was applied for the simultaneous determination of LIG and PHE from a new drug delivery system. The results indicate that the method is simple, specific, selective and reliable for simultaneous quantitative determination of LIG and PHE as bulk drug and from formulations.

Feasibility of an in vitro microbiological model as an alternative to the rabbit eye model.

Ocular inserts of gentamicin sulfate with polyvinyl alcohol (PVA) 1.5%, 2.0%, and 2.5% and a combination of methyl cellulose 2% and Eudragit NE 30D 30%, 35%, and 40% w/w of methyl cellulose were fabricated by a casting technique. The inserts were sterilized by gamma radiation at 25 kGy and tested for sterility. The microbiological efficacy of the ocular inserts against Staphylococcus aureus ATCC 6538P and Pseudomonas aeruginosa NCIM 2200 was evaluated by developing an in vitro microbiological model and an in vivo noninvasive rabbit eye model. Parameters of the in vitro microbiological model were varied, and the results correlated with a noninvasive rabbit eye model. The in vitro model proved to be a viable alternative to the rabbit eye model in evaluating the microbiological efficacy of gentamicin sulfate ocular inserts.

Comparative pharmacodynamic-pharmacokinetic correlation of oral sustained-release theophylline formulation in adult asthmatics.

A sustained-release formulation of theophylline with an innovative release mechanism was evaluated in adult asthmatics. The pharmacodynamics and pharmacokinetic behavior of this formulation was compared with a market formulation (Theobid). The formulations, each containing 200 mg of anhydrous theophylline, were evaluated in six male subjects, 40-55 years of age, 151-169 cm in height, 41-60 kg in weight, who were nonsmokers with moderate chronic obstructive pulmonary disease (COPD); the study was a randomized, single-dose, open, complete crossover study with an interval of 1 week. Written consent was obtained from the patients prior to the trial. Plasma samples were obtained at 0, 1, 2, 4, 6, 8, 10, and 12 hr postadministration. Pulmonary functions were simultaneously recorded using an Erich Jaeger spirometer. Plasma theophylline assays were performed using high-performance thin-layer chromatography (HPTLC). Individual bioavailability parameters were obtained using the S-Inv computer program. Pharmacodynamic-pharmacokinetic correlation was studied using the Excel 95 version 7.0 Regression Statistics program. The test formulation (innovator) was found to be comparable with the marketed product with respect to tmax, t1/2 and Kel (p < .05). A significant difference in the means of Cmax and AUC0-12 between the innovator and the market formulation indicated a superior extent of absorption from the innovator formulation. A good pharmacodynamic-pharmacokinetic correlation was observed when plasma theophylline concentration was compared with forced expiratory volume.

High-performance thin-layer chromatographic determination of theophylline in plasma.

A high-performance thin-layer chromatographic method for quantification of theophylline from plasma is described. The calibration curves of theophylline in methanol and in plasma were linear in the range 20-100 ng. The correlation coefficients were 0.9971+/-0.0011 and 0.9955+/-0.0003 for standard curves in methanol and in plasma, respectively. The limit of quantitation of theophylline in human plasma (assay sensitivity) was 20 ng and no interference from endogenous compounds was observed. The recovery of theophylline from human plasma using the described assay procedure was 89%. The mean relative standard deviations for intra- and inter-day analyses were 1.67% and 2.34% for 50 ng and 2.25% and 3.14% for 75 ng theophylline concentration, respectively. The method was utilized to monitor plasma concentration of theophylline post-administration of sustained release tablets in human patient volunteers.

High-performance thin-layer chromatographic determination of diltiazem hydrochloride as bulk drug and in pharmaceutical preparations.

A simple, rapid, selective and precise high-performance thin-layer chromatographic method for the analysis of diltiazem hydrochloride both as a bulk drug and in pharmaceuticals is reported. The mobile phase composition was ethyl acetate-methanol-strong ammonia solution (80:10:10, v/v). Densitometric analysis of diltiazem hydrochloride was carried out at 238 nm. The calibration curve of diltiazem hydrochloride in distilled water was linear in the range 40-400 ng. The mean value of correlation coefficient, slope and intercept were 0.997+/-0.0008, 0.0617+/-0.0012 and 7.16+/-0.2562, respectively. The limits of detection and quantitation were 20 ng and 40 ng, respectively. The recovery of diltiazem hydrochloride was about 99.5%. The method was utilized to analyse diltiazem hydrochloride from conventional and sustained release tablets in the presence of commonly used excipients.

Fluorodensitometric evaluation of gentamicin from plasma and urine by high-performance thin-layer chromatography.

High-performance thin-layer chromatographic (HPTLC) analysis of gentamicin by in situ fluorodensitometric evaluation of its 4-chloro-7-nitrobenzo-2-oxa-1,3-diazole (NBD-Cl) derivative is presented. The aminoglycoside components separated on silica gel plates using chloroform-methanol-20% ammonium hydroxide (2.4:2.2:1.5, v/v/v) as the mobile phase were reacted with NB-Cl to yield highly fluorescent derivatives. The calibration curves of gentamicin in water, plasma and urine were linear in the range 40-200 ng. The mean values of intercept, slope and correlation coefficient were 16.82 +/- 0.473, 6.83 +/- 0.015 and 0.9968 +/- 0.0017 for standard curves in water, 17.35 +/- 0.375, 6.85 +/- 0.018 and 0.9941 +/- 0.0012 for standard curves in plasma and 14.35 +/- 0.286, 6.86 +/- 0.002 and 0.9933 +/- 0.0011 for standard curves in urine respectively. The analytical technique was validated for within-day and day-to-day variation. The results indicate that HPTLC, coupled with in situ fluorodensitometry, is a reliable and valuable technique for quantitative analysis of the bulk drug gentamicin and gentamicin from urine and plasma.

High-performance thin-layer chromatographic determination of flurbiprofen in plasma.

A high-performance thin-layer chromatographic (HPTLC) method for the assay of flurbiprofen in plasma is reported. The drug was extracted from acidified plasma with hexane-diethyl ether (80:20). The mobile phase composition was n-hexane-ethyl acetate-glacial acetic acid (60:30:10). Densitometric analysis of flurbiprofen was carried out at 247 nm. The calibration curves of flurbiprofen in methanol and in plasma were linear in the range 40-400 ng. The mean values of correlation coefficient, slope and intercept were 0.995 +/- 0.003, 0.075 +/- 0.002 and 4.39 +/- 0.05 for standard curves in methanol and 0.992 +/- 0.002, 0.066 +/- 0.007 and 3.40 +/- 0.72 for standard curves in plasma, respectively. The limit of quantitation for flurbiprofen in human plasma was 40 ng, and no interference was found from endogenous compounds. The recovery of flurbiprofen from human plasma using the described extraction procedure was about 87%. The coefficient of variation for within-day and between-day analyses was 2.53% and 3.96% for 200 ng and 1.76% and 2.30% for 400 ng flurbiprofen concentration, respectively. The method was utilized to monitor plasma concentration of flurbiprofen post administration of sustained release capsules in human patient volunteers.

High-performance thin-layer chromatographic determination of ibuprofen in plasma.

A high-performance thin-layer chromatographic (HPTLC) method for quantitation of ibuprofen from plasma is described. The drug was extracted from acidified plasma with hexane-isopropanol (85:15). The mobile phase composition was n-hexane-ethyl acetate-anhydrous acetic acid (75:25:2). Densitometric analysis of ibuprofen was carried out at 222 nm. The calibration curves of ibuprofen in chloroform and in plasma were linear over the range 2-20 micrograms. The mean values of intercept, slope and correlation coefficient were 0.0422 +/- 0.0018. 1.0356 +/- 0.0213 and 0.9976 +/- 0.0013 for standard curves in chloroform and 0.1044 +/- 0.003, 0.8759 +/- 0.0213 and 0.9939 +/- 0.001 for standard curves in plasma, respectively. The limit of detection of ibuprofen from human plasma (assay sensitivity) was 50 ng and no interference was found from endogenous compounds. The recovery of ibuprofen from human plasma using the described extraction procedure was about 85%. The mean relative standard deviations for within-day and between-day analyses were 2.24 and 2.6% for 5 micrograms and 3.67 and 3.2% for 15 micrograms ibuprofen concentration, respectively. The method was utilized to monitor the plasma concentration of ibuprofen post administration of sustained release capsules in human patient volunteers.

A bioadhesive delivery system as an alternative to infiltration anesthesia.

OBJECTIVE: The aim of this study was to determine the feasibility of a novel saliva-activated bioadhesive drug delivery system of lidocaine hydrochloride as a viable alternative to infiltration anesthesia in dentistry. STUDY DESIGN: The study was carried out in three stages. First, the drug delivery system (DDS) was subjectively evaluated for adherence to the gingival mucosa and peak effect of anesthesia. In the second stage, a comparative subjective and objective evaluation of the DDS with a marketed topical gel preparation was carried out. Finally an open label, nonblinded clinical trial was carried out using the exodontia model. A total of 49 extractions were attempted in 41 patients. The effect of the following variables was investigated in the study: (1) jaw (maxillary and mandibular), (2) overall mobility, (3) position-notation of tooth (1, 2, 3, 4 ...). The positive extractions were statistically analyzed by the t test comparison of means of two independent variables. RESULTS: Subjective evaluation revealed that the DDS adheres to the gingiva within a minute and produces peak effect in 15 minutes. Comparative study revealed that the DDS produces greater depth of anesthesia than the marketed topical gel. Of 49 extractions attempted with the DDS, 40 were successful, giving an efficacy of 81.63%. CONCLUSION: The novel saliva-activated bioadhesive drug delivery system of lidocaine hydrochloride exhibits potential as a feasible alternative to infiltration anesthesia in dentistry.