Ismail Khan

Development and evaluation of pluronic- and methylcellulose-based thermoreversible drug delivery system for insulin

Abstract The objective of the current work was to develop and evaluate thermoreversible subcutaneous drug delivery system for Insulin. Thermoreversible in-situ gel system was developed and evaluated both in-vitro and in-vivo comprising of pluronic F-127 alone or in combination with methylcellulose in different ratios. The drug release kinetics and mechanism was predicted by applying various mathematical models to the in-vitro dissolution data. Rabbits were used as animal model following subcutaneous injection to predict various pharmacokinetic parameters by applying Pk-Summit® software. The in-vitro and in-vivo data revealed that the formulation IPM 15/3 consisting of the pluronic F-127 (15% w/v) and methylcellulose (3% w/v) was the most robust and capable formulation for extending the drug release and maintaining basal plasma insulin level between 10 and 40 µU/ml for 240 h (10 d).

A simple, rapid and sensitive RP-HPLC-UV method for the simultaneous determination of sorafenib & paclitaxel in plasma and pharmaceutical dosage forms: Application to pharmacokinetic study

A simple, economical, fast, and sensitive RP-HPLC-UV method has been developed for the simultaneous quantification of Sorafenib and paclitaxel in biological samples and formulations using piroxicam as an internal standard. The experimental conditions were optimized and method was validated according to the standard guidelines. The separation of both the analytes and internal standard was achieved on Discovery HS C18 column (250mm×4.6mm, 5μm) using Acetonitrile and TFA (0.025%) in the ratio of (65:35V/V) as the mobile phase in isocratic mode at a flow rate of 1ml/min, with a wavelength of 245nm and at a column oven temperature of 25°Cin a short run time of 12min. The limits of detection (LLOD) were 5 and 10ng/ml while the limits of quantification (LLOQ) were 10 and 15ng/ml for sorafenib and paclitaxel, respectively. Sorafenib, paclitaxel and piroxicam (IS) were extracted from biological samples by applying acetonitrile as a precipitating and extraction solvent. The method is linear in the range of 15-20,000ng/ml for paclitaxel and 10-5000ng/ml for sorafenib, respectively. The method is sensitive and reliable by considering both of its intra-day and inter-day co-efficient of variance. The method was successfully applied for the quantification of the above mentioned drugs in plasma. The developed method will be applied towards sorafenib and paclitaxel pharmacokinetics studies in animal models.

Simultaneous determination of moxifloxacin and ofloxacin in physiological fluids using high performance liquid chromatography with ultraviolet detection

A novel, sensitive and validated RP-HPLC-UV method was developed for simultaneous determination of moxifloxacin and ofloxacin using timolol maleate as internal standard in physiological fluids. Different experimental parameters were optimized and validated according to international guidelines. Complete separation of the analytes was achieved with Kromasil 100-5C18 analytical column (250mm×4.6mm×5μm), methanol and 0.05% trifloroacetic acid (TFA) (38:62v/v) were used as mobile phase, pumped at flow rate of 1.1ml/min in isocratic phase, column oven temperature maintained at 45°C and detection wavelength of 290nm. Protein precipitation method was applied to extract the drugs from human plasma and bovine aqueous humor samples using methanol as precipitating solvent. This method is linear in concentration range of 0.018-100μg/ml for moxifloxacin and 0.014-20μg/ml for ofloxacin. The recoveries of the method were 97.52 and 97.39% in human plasma for MX and OFN respectively, while in aqueous humor 94.48% for MX. The LOD values in plasma were found to be 10.0 and 8.00ng/ml for MX and OFN respectively, while their respective LOQ values were 18.0 and 14ng/ml. In aqueous humor the LOD and LOQ for MX were 16.0 and 24ng/ml respectively. In future, this method will be used to study the pharmacokinetic profile of moxifloxacin and ofloxacin in biological fluids and pharmaceutical products.

Simultaneous determination of methotrexate and metoclopramide in physiological fluids using RP-HPLC with ultra-violet detection; application in evaluation of polymeric nanoparticles

ABSTRACT Methotrexate (MTX) is an anticancer drug while metoclopramide (MCP) is an antiemetic agent. Both the drugs are commonly coprescribed to avoid the emesis caused by anticancer drug. In this study, a novel, rapid, sensitive, and cost-effective reverse-phase high-performance liquid chromatography method was developed and validated for simultaneous determination of the methotrexate and metoclopramide in biological and pharmaceutical samples using sparfloxacin as internal standard. The analytes were separated on a Kromasil 100-5C18 RP (250 × 4.6 mm, 5 µm) column, methanol, and 0.05% trifloroacetic acid (36:64 v/v) as mobile phase with a flow rate of 1 mL/min, detection wavelength of 290 nm, and column oven temperature at 40°C. Both the analytes were extracted from physiological fluids (bovine aqueous humor, vitreous humor, and human plasma) using mixture of methanol and 10% perchloric acid (50:50 v/v). The method was linear over the concentration range of 0.025–1.0 µg/mL for methotrexate and 0.030–1.0 µg/mL for metoclopramide. The % recovery from human plasma was 98.57 and 96.74% for MTX and MCP, respectively, while from aqueous humor and vitreous humor was 95.84 and 98.51% for MTX. The developed method was applied for in vitro release of MTX from polymeric nanoparticles and can be applied for analysis of pharmaceutical and biological samples containing both the drugs. GRAPHICAL ABSTRACT

Pharmacokinetic Profiling of a Novel Flavonoid “Viscosine” from Dodonaea viscosa Using High Performance Liquid Chromatography

Pharmacokinetic (PK) profiling of a novel flavonoid “Viscosine” was carried out in healthy rabbits following both IV and oral administration. Various PK parameters were investigated using the developed HPLC–UV method. The concentration of the Viscosine in plasma samples following both IV and oral administration was plotted as a function of time on normal and semi-log graph papers. The plasma drug concentration as a function of time profile of the Viscosine following IV bolus administration and oral administration showed the bi-exponential decline that indicates that PK of the Viscosine follows two compartment open model. The Viscosine is rapidly but incompletely absorbed following oral administration from hard gelatin capsules and tmax was achieved just in 0.5 hr (30 min). The mean ± SD of Cmax was 0.981 ± 0.021 µg/mL. The very low plasma drug concentration achieved shows that Viscosine has lower permeability following oral administration. Similarly, following IV bolus drug administration, the plasma drug concentration as a function of time curve of Viscosine was a bi-exponential curve that follows two compartment open model. Viscosine is readily distributed and established equilibrium between central and peripheral compartments. Higher volume of distribution (Vd) shows the longer stay in the peripheral compartments. The β-elimination half-life is approximately 3.8 hr. The AUC values also indicate the distribution of the drug in various body fluids. In summary, the bioavailability of the drug after oral administration (F = 0.32) indicates that Viscosine is a low soluble drug; however, the Vd was higher compared with the IV bolus injection while MRT was about 15.45 hr. These studies indicate that capsules can be used as a suitable dosage form for the administration of Viscosine.

Modulation of pH-Independent Release of a Class ΙΙ Drug (Domperidone) from a Polymeric Matrix Using Acidic Excipients

Drug release from polymeric matrix systems is the rate-limiting step for drug bioavailability and is determined by drug solubility; most drugs show pH-dependent solubility. Polymeric matrices remain in the gastrointestinal tract for a longer period of time and are exposed to environments of varying pH, which can adversely affect drug release. In the present study, the pH-independent drug release of domperidone was achieved by modifying the microenvironmental pH of a swollen polymeric matrix using acidic excipients (citric acid and tartaric acid). Matrices were prepared by a water-based, wet-granulation technique and evaluated for various official and unofficial parameters. In vitro drug release was studied using USP dissolution apparatus and pH 6.80 phosphate buffer as dissolution medium. Release kinetics was evaluated according to various mathematical models. Results show that domperidone release can be effectively modified by inclusion of acidic excipients in the formulations. Acidic excipients modulated microenvironmental pH and avoided the effect of dissolution medium pH on drug release. The resultant formulations are easy to prepare and scale up for commercial manufacturing. Better pH-independent release, following zero-order kinetics, was achieved with tartaric acid.