Optimization of the experimental parameters of fluticasone propionate microparticles for pulmonary delivery using a box behenken design.

The objective of this study was to examine extensively the influences of formulation and process variables on the microparticles. The microparticles were generated by the spray-drying technique using polymer chitosan, mannitol along with L-leucine. The effects of various experimental parameters such as polymer concentration, inlet temperature, and feed flow rate on particle size and production yields were evaluated by means of experimental box-behnken design. Multiple regression analysis was carried out and response surfaces were obtained. Optimized formulation and check points batches were selected by feasibility and grid search. Experimental design it was evaluated that inlet temperature and polymer concentration influence on the production yield. Feed flow rate impact on particle size. Results showed that spray drying technique yield 985 to 4060 nm indicate micro size range and production yield was found in between 27.01-52.96%. The selection of appropriate parameters yielded spray-dried microparticles characterized by narrow dimensional distribution. In our present work, prepared microparticles using the spray-drying technique and systematically estimated their feasibility for the pulmonary delivery of microparticles by careful investigations of their characteristics and aerosolization properties. Spray drying technique yield optimum size for deposition beyond the narrow airway into the alveoli and suitable for respiratory deposition.

Development and in vivo evaluation of silver sulfadiazine loaded hydrogel consisting polyvinyl alcohol and chitosan for severe burns.

A new Hydrogel containing silver Sulfadiazine (SSD) was developed for enhanced burns wound healing. The hydrogel was prepared by cross-linking of PVA and Chitosan by freeze thawing method. Their gel properties, moisture retaining capacity, fluid uptake capacity, in vitro release study, in vivo burn healing effect were evaluated. Chitosan and PVA cross linking decreased gel fraction upto 70% determined the good gel properties. This cross linked hydrogel increased the Swelling ratio and Water vapour transmission rate (WVTR) which provides the sustained release of drug and moist environment for healing respectively. The hydrogel containing 7.5% of PVA, 0.75% of chitosan found to have increased gel strength, higher water vapour transmission rate and fluid uptake capacity suitable for faster healing of burns. This hydrogel also sustained the release of 1% SSD required for longer antimicrobial activity and found better in vivo burn healing capacity as compared to marketed preparation. Thus hydrogel containing 7.5% of PVA, 0.75% of chitosan and 1% SSD is a potential burns dressing with better gel properties and excellent burns healing capacity.

Targeting CYP450 modulation to decrease the risk of induced cataract in the experimental model.

BACKGROUND: Diabetes is one of the major causes of cataract. Some drugs prescribed for the treatment of diabetes are the modulators of CYP450, which may alter the risk of cataract. OBJECTIVE: To study the effect of CYP450 modulation in galactosemic cataract. MATERIALS AND METHODS: Male Sprague-Dawley suckling rats were allotted to four groups (n = 6), as follows: Group 1: Normal control, Group 2: Galactose control, Group 3: CYP450 inhibitor pretreated and Group 4: CYP450 inducer pretreated. Cataract was induced in animals of all groups except group 1 by feeding them galactose (50%), 21 days after parturition. From the eighteenth day of life, CYP450 inhibitor (nifedipine; 8.1 mg/kg) and CYP450 inducer (pioglitazone; 3.8 mg/kg) were given orally to groups 3 and 4, respectively. The maturation pattern of the cataract was observed by an operating microscope, every third day. Biochemical changes in the lenses of all groups, for example, CYP450 activity expressed as ΅M NADPH oxidized / unit time, alterations in the levels of total proteins, soluble proteins, and reduced glutathione (GSH) following the induction of cataract, were estimated. RESULTS: The microscopic examination of the lenses indicated that CYP450 inhibitor pre-treatment delayed (fourteenth day) the occurrence of cataract, while CYP450 inducer pretreatment demonstrated an early (ninth day) cataract as compared to galactose control rats (twelfth day). A significant decrease and increase in CYP450 activity was observed with the CYP450 inhibitor and inducer pre-treatment, respectively. There was no alteration in the GSH level, but a significant increase in total and soluble protein was found in groups 3 and 4 as compared to group 2. CONCLUSION: CYP450 may have a role in the initiation of cataract without any effect on the maturation pattern, as revealed by the delayed occurrence of cataract with the CYP450 inhibitor and an early onset of cataract with the CYP450 inducer.

Evaluation of the effect of Myrica sapida on bronchoconstriction and bronchial hyperreactivity.

The present investigation was undertaken to evaluate the bronchodilator and bronchial hyperreactivity of the stem bark of Myrica sapida. Experimental models studied were histamine induced bronchospasm in guinea pigs, bronchoalveolar lavage fluid (BALF) in egg albumin sensitized guinea pigs, histamine release from the lung tissues of sensitized guinea pigs and histopathological studies. Ethanolic extract of M. sapida (75 mg/kg, p.o., for 7 days) showed significant protection against histamine aerosol induced bronchospasm. Significant decrease in the total and differential leukocyte counts in BALF and prevention of egg albumin induced histamine release from chopped lung tissues of sensitized guinea pigs was observed on chronic administration of ethanolic extract of M. sapida (75 mg/kg, p.o., for 15 days). Histological examination of the section of lung from sensitized guinea pigs treated with ethanolic extract of M. sapida (75 mg/kg, p.o., for 15 days) was comparable to that of the control group. These results suggest that M. sapida possesses not only bronchodilator activity but also decreases bronchial hyperresponsiveness by decreasing the infiltration of inflammatory mediators like eosinophils, neutrophils in BALF and inhibiting histamine release from lungs of sensitized guinea pigs.

Mathematical evaluation of similarity factor using various weighing approaches on aceclofenac marketed formulations by model-independent method.

The US Food and Drug Administration's (FDA's) guidance for industry on dissolution testing of immediate-release solid oral dosage forms describes that drug dissolution may be the rate limiting step for drug absorption in the case of low solubility/high permeability drugs (BCS class II drugs). US FDA Guidance describes the model-independent mathematical approach proposed by Moore and Flanner for calculating a similarity factor (f2) of dissolution across a suitable time interval. In the present study, the similarity factor was calculated on dissolution data of two marketed aceclofenac tablets (a BCS class II drug) using various weighing approaches proposed by Gohel et al. The proposed approaches were compared with a conventional approach (W = 1). On the basis of consideration of variability, preference is given in the order of approach 3 > approach 2 > approach 1 as approach 3 considers batch-to-batch as well as within-samples variability and shows best similarity profile. Approach 2 considers batch-to batch variability with higher specificity than approach 1.

Stability Indicating RP-HPLC Estimation of Atorvastatin Calcium and Amlodipine Besylate in Pharmaceutical Formulations.

A simple, specific, accurate and stability indicating reversed phase high performance liquid chromatographic method was developed for the simultaneous determination of atorvastatin calcium and amlodipine besylate in tablet dosage forms. A phenomenex Gemini C-18, 5 µm column having 250×4.6 mm i.d. in isocratic mode, with mobile phase containing 0.02 M potassium dihydrogen phosphate:acetonitrile:methanol (30:10:60, v/v/v) adjusted to pH 4 using ortho phosphoric acid was used. The flow rate was 1.0 ml/min and effluents were monitored at 240 nm. The retention times of atorvastatin calcium and amlodipine besylate were 11.6 min and 4.5 min, respectively. The calibration curves were linear in the concentration range of 0.08-20 µg/ml for atorvastatin calcium and 0.1-20 µg/ml for amlodipine besylate. Atorvastatin calcium and amlodipine besylate stock solutions were subjected to acid and alkali hydrolysis, chemical oxidation and dry heat degradation. The degraded product peaks were well resolved from the pure drug peak with significant difference in their retention time values. The proposed method was validated and successfully applied to the estimation of atorvastatin calcium and amlodipine besylate in combined tablet dosage forms.

Stability Indicating RP-HPLC Estimation of Nebivolol Hydrochloride in Pharmaceutical Formulations.

A simple, specific, accurate and stability indicating reversed phase liquid chromatographic method was developed for the determination of nebivolol hydrochloride in tablet dosage forms. A phenomenex Gemini C-18, 5 µm column having 250×4.6 mm i.d., with mobile phase containing methanol: acetonitrile: 0.02 M potassium dihydrogen phosphate (60:30:10, v/v/v; pH 4.0) was used. The retention time of nebivolol hydrochloride was 2.6 min. The linearity for nebivolol hydrochloride was in the range of 0.2-10 µg/ml. The recovery was found to be in the range of 98.68-100.86%. The detection limit and quantification limit were found to be 0.06 µg/ml and 0.2 µg/ml, respectively. Nebivolol stock solutions were subjected to acid, alkali and neutral hydrolysis, chemical oxidation and dry heat degradation. The degraded product peaks were well resolved from the pure drug peak with significant difference in their retention time values. The proposed method was validated and successfully applied to the estimation of nebivolol hydrochloride in tablet formulations.

Mechanism of the antihyperlipaemic activity and pharmacokinetics of 2-chloromethyl-5,6,7,8-tetrahydrobenzo(b)thieno[2,3-d]pyrimidin-4(3H)-o ne.

The pharmacokinetics and the mechanism of action of the antihyperlipaemic compound 2-chloromethyl-5,6,7,8-tetrahydrobenzo(b)thieno[2,3-d]pyrimidin-4(3H)-on e (CAS 89587-03-3, LM-1554) have been studied. Serum concentrations were determined by reverse phase HPLC using methanol : water (60 : 40) as the solvent system. The results of pharmacokinetic studies suggest that the compound LM-1554 is poorly absorbed from the gastrointestinal tract after the oral administration in dogs and rabbits. The volume of distribution (Vd) was found to be low. The poor bioavailability (3-4%) and low volume of distribution of the compound LM-1554 suggest the gastrointestinal tract as the site of action for the antihyperlipaemic activity. This hypothesis is substantiated by the observations that the compound was found active in rabbits only when administered orally and found inactive by the parenteral route. Further, the cholesterol levels were found to increase in blood samples collected from the portal vein after oral administration of cholesterol in coconut oil to rats. This increase was found to be prevented by the compound LM-1554. In conclusion, the compound LM-1554 has a potential to be developed as an antihyperlipaemic agent. The mechanism of action of the compound LM-1554 appears to consist in the inhibition of cholesterol absorption in the gastrointestinal tract.