Drug Content Estimation Research Articles

Preparation and Evaluation of Silymarin Controlled Release Tablets Prepared Using Natural Gums

The aim of the study was to formulate and evaluate silymarin controlled release (CR) tablets using natural polymers (xanthan gum and guar gum) CR Tablets of silymarin were prepared by direct compression method at different ratios of 1:0.25, 1:0.5 and 1:0.75 (drug:polymers). The powder blend was evaluated for angle of repose, bulk density, tapped density, compressibility index and Hausner ratio. The powder blend showed satisfactory flow properties. The silymarin tablets are evaluated for general appearance, hardness test, friability test, weight variation and drug content estimation. All the tablets passed the tests. The interactions between the drug with highest proportion of polymers were determined by using FTIR studies. The FTIR study reveals that there is no interaction between drug and polymers. The invitro release study was carried out using 900ml of phosphate buffer pH 7.4 for 10 hours using USP type II dissolution apparatus. The results of invitro release studies of CR tablets of silymarin were compared with control (without polymer).

Simple UV and visible spectrophotometric methods for the determination of doxycycline hyclate in pharmaceuticals

Doxycycline hyclate (DOX), a broad spectrum antibiotic with activity against a wide range of gram-positive and gram-negative bacteria, is widely used as a pharmacological agent and as an effector molecule in inducible gene expression system. Three simple, selective, rapid, accurate, precise and cost-effective spectrophotometric methods for the determination of DOX in bulk drug and in tablets have been developed and validated. First method (method A) is based on the measurement of absorbance of DOX in 0.1 M HCl at 240 nm. The second method (method B) is based on the measurement of yellow chromogen at 375 nm which is formed in 0.1 M NaOH. The third method is based on the measurement of 2: 1 complex formed between DOX and iron(III) in H2SO4 medium, the complex peaking at 420 nm (method C). The optimum conditions for all the three methods are optimized. Beer’s law was obeyed over the ranges 2.5–50.0, 1.50–30.0 and 10–100 g/mL for method A, method B and method C, respectively. The apparent molar absorptivity values are calculated to be 1.03 × 104, 1.73 × 104, and 5.21 × 103 L mol−1 cm−1 for method A, method B, and method C, respectively. The Sandell sensitivity, limit of detection (LOD) and limit quantification (LOQ) values are also reported. All the methods were validated in accordance with current ICH guidelines. The developed methods were employed with high degree of precision and accuracy for the estimation of total drug content in commercial tablet formulations of DOX.

Formulation and In-vitro Evaluation of Orally Disintegrating Tablets of Olanzapine-2-Hydroxypropyl-β-Cyclodextrin Inclusion Complex.

The aim of this study was to design orally disintegrating tablets of Olanzapine and to complex Olanzapine with 2-hydroxypropyl-β- cyclodextrin with special emphasis on disintegration and dissolution studies. Phase solubility studies demonstrated the formation of 1:1 molar inclusion complex by kneading method. Tablets were prepared by using superdisintegrants namely, sodium starch glycolate, croscarmellose sodium, crospovidone, tulsion 339, and indion 414. Complex was characterized using infrared spectroscopy, drug content estimation, saturated solubility study, diffrerential scanning calorimetry and X-ray diffractometry. 5% w/w croscarmellose sodium showed the minimum disintegration time 39 ± 1.76 sec and in-vitro drug release 99.19 ± 0.18% within 6 min. In general, solubility of Olanzapine can be improved by complexing with 2-hydroxypropyl-β- cyclodextrin. Croscarmellose sodium can be used for faster disintegration of tablets.

Spectrophotometric determination of ofloxacin in pharmaceuticals and human urine

Three simple and sensitive spectrophotometric methods are described for the determination of ofloxacin (OFX) in pharmaceuticals and in spiked human urine. First and second methods are based on the measurement of absorbance of OFX in 0.1 M HCl at 293 nm (method A) and 0.1 M NaOH at 287 nm, respectively. The third method is based on the measurement of 2:1 complex formed between OFX and iron(III) in H2SO4 medium, the complex peaking at 420 nm (method C). The optimum conditions for all the three methods are optimized. Beer’s law is obeyed over the ranges 0.63-12.5 using method A and method B, and 10-120 μg mL-1 using method C. The apparent molar absorptivity values are calculated to be 3.5 × 104, 2.76 × 104 and 2.51 × 103 L mol-1cm-1 for method A, method B and method C, respectively. The Sandell sensitivity, limit of detection (LOD) and limit quantification (LOQ) values are also reported. All the methods were validated in accordance with current ICH guidelines. The developed methods were employed with high degree of precision and accuracy for the estimation of total drug content in commercial tablet formulations of DOX.

Spectrophotometric determination of ofloxacin in pharmaceuticals and human urine

Three simple and sensitive spectrophotometric methods are described for the determination of ofloxacin (OFX) in pharmaceuticals and in spiked human urine. First and second methods are based on the measurement of absorbance of OFX in 0.1 M HCl at 293 nm (method A) and 0.1 M NaOH at 287 nm, respectively. The third method is based on the measurement of 2:1 complex formed between OFX and iron(III) in H2SO4 medium, the complex peaking at 420 nm (method C). The optimum conditions for all the three methods are optimized. Beer's law is obeyed over the ranges 0.63-12.5 using method A and method B, and 10-120 µg mL-1 using method C. The apparent molar absorptivity values are calculated to be 3.5 × 104, 2.76 × 104 and 2.51 × 103 L mol-1cm-1 for method A, method B and method C, respectively. The Sandell sensitivity, limit of detection (LOD) and limit quantification (LOQ) values are also reported. All the methods were validated in accordance with current ICH guidelines. The developed methods were employed with high degree of precision and accuracy for the estimation of total drug content in commercial tablet formulations of DOX. The results obtained from human spiked urine are satisfactory and recovery values are in the range 95.5-106.6%.

Formulation and Evaluation of a Novel In Situ Gum Based Ophthalmic Drug Delivery System of Linezolid

Abstract A major problem in ocular therapeutics is the attainment of optimal drug concentration at the site of action, which is compromised mainly due to precorneal loss resulting in only a small fraction of the drug being ocularly absorbed [1]. The effective dose administered may be altered by increasing the retention time of medication into the eye by using in situ gel forming systems. The aim of the present investigation is to prepare and evaluate novel in situ gum based ophthalmic drug delivery system of linezolid. Hydroxypropyl guar (HPG) and xanthum (XG) were used as gum with the combination of hydroxyethyl cellulose (HEC), carbopol (CP), and sodium alginate as viscosity enhancing agents. Suitable concentrations of buffering agents were used to adjust the pH to 7.4. All the formulations were sterilized in an autoclave at 121°C for 15mins. The formulations were evaluated for clarity, pH measurement, gelling capacity, drug content estimation, rheological study, in vitro diffusion study, antibacterial activity, isotonicity testing, eye irritation testing. The developed formulations exhibited sustained release of drug from formulation over a period of 6hr thus increasing residence time of the drug. The optimized formulations were tested for eye irritation on albino rabbit (male) using the Draize test protocol with crossover studies. The formulations were found to be non-irritating with no ocular damage or abnormal clinical signs to the cornea, iris or conjunctiva observed. Thus these in situ gelling systems containing gums may be a valuable alternative to the conventional systems.

Rapid and sensitive spectrofluorimetric method for the estimation of celecoxib and flurbiprofen

In this study new, rapid and sensitive spectrofluorimetric methods for the quantitative estimation of celecoxib and flurbiprofen in pure form and in their pharmaceutical dosage forms were developed. The solvent systems, wavelengths of detection (excitation and emission) were optimized in order to maximize the sensitivity and minimize the cost of analysis for both the drugs. No extraction procedure was employed for analysis of these compounds in their formulation matrix, which reduced the time of sample preparation. The excitation and emission wavelengths were found to be 256 nm and 403 nm respectively for celecoxib in water and 250 nm and 314 nm respectively for flurbiprofen in 1:1 mixture of methanol and 0.1N sulphuric acid. The linear regression equations obtained by least square regression method for fluorescence intensity (FI) and concentration in ng/ml (conc) were FI=1.2874´conc+22.647, for celecoxib; and FI=27.7970´conc+46.049, for flurbiprofen. The limit of detection as per the error propagation theory was found to be 4.97 ng/ml and 0.99 ng/ml for celecoxib and flurbiprofen respectively. The developed methods were successfully employed with high degree of precision and accuracy for the estimation of total drug content in two commercial capsule formulations of celecoxib and two ophthalmic drops of flurbiprofen. The results of analysis were treated statistically, as per International Conference on Harmonization guidelines for validation of analytical procedures, and by recovery studies. It was concluded that developed methods are simple, accurate, sensitive, precise and reproducible and could be applied directly and easily to the pharmaceutical preparations of celecoxib and flurbiprofen.

Determination of flurbiprofen in pharmaceutical formulations by UV spectrophotometry and liquid chromatography

In this study, a new and rapid UV spectrophotometric (UV) method and a reversed phase high performance liquid chromatographic (LC) method were developed for quantitative estimation of flurbiprofen, a non-selective, non-steroidal, anti-inflammatory drug (NSAID), in pure form and in pharmaceutical dosage form. The solvent system, wavelength of detection, chromatographic conditions were optimized in order to maximize the sensitivity of both the proposed methods. The linear regression equations obtained by least square regression method were Abs=7.5906×10 −2 concentration (μg/ml) + (−) 4.6210×10 −2 for the UV method, and peak area=1.2652×10 2 concentration (ng/ml) + 1.4830×10 3 for the LC method. The detection limit as per the error propagation theory was found to be 0.34 μg/ml for UV method and 15 ng/ml for LC method. The developed methods were successfully employed with high degree of precision and accuracy for the estimation of total drug content in two commercial ophthalmic drops of flurbiprofen. The results of analysis were treated statistically, as per USP 2000 and International Conference on Harmonization (ICH) guidelines for validation of analytical procedures, and by recovery studies. The results obtained from UV method were comparable with those obtained by using LC. It was concluded that both the developed methods are equally accurate, sensitive, precise, reproducible, robust and rugged and could be applied directly and easily to the pharmaceutical preparations of flurbiprofen. However, LC method is useful at very low level (ng/ml), whereas UV method is suitable at μg/ml level.

Determination of celecoxib in pharmaceutical formulations using UV spectrophotometry and liquid chromatography

A new UV spectrophotometric method (UV method) and a reversed phase liquid chromatographic method (LC method) for the quantitative estimation of celecoxib, a selective COX-2 inhibitor, in pure form and in solid dosage form were developed in the present study. The linear regression equations obtained by least square regression method, were Abs=4.949×10 −2 · Conc. (in μg/ml)+1.110×10 −2 for the UV method and Area under the curve=5.340×10 1 · Conc. (in ng/ml)+3.144×10 2 for the LC method, respectively. The detection limit, as per the error propagation theory, was found to be 0.26 μg/ml and 25 ng/ml, respectively, for the UV and LC methods. The developed methods were employed with a high degree of precision and accuracy for the estimation of total drug content in three commercial capsule formulations of celecoxib. The results of analysis were treated statistically, as per International Conference on Harmonisation (ICH) guidelines for validation of analytical procedures, and by recovery studies. The results were found to be accurate, reproducible and free from interference and better than the earlier reported methods.

Effect of Additives on Stability of Etoposide in PLGA Microspheres

The purpose of this article was to determine the shelf life of etoposide in poly(lacticco-glycolic acid) (PLGA) microspheres prepared with and without additives (i.e., tricaprin and isopropyl myristic acid ester [IPM]). The microspheres were prepared by a single-emulsion solvent extraction technique with and without 25% w/w additive. The batches of microspheres were subjected to an accelerated stability study at two elevated temperatures (70°C and 80°C or 80°C and 90°C). Samples were taken at 7, 14, 21, 28, and 35 days for estimation of drug content by high-performance liquid chromatography (HPLC). The drug stability in the microspheres was determined by plotting the log percentage drug remaining versus time to obtain the degradation rate constant k of etoposide at the measured temperature. This degradation rate constant was then used in the Arrhenius equation to obtain the activation energy of etoposide, which was utilized to determine the shelf life of the microspheres at room temperature. The results showed that all three microsphere formulations had good long-term stability at room temperature (6.62-8.86 years at 25°C). The plain microspheres were shown to possess a shelf life of 6.62 years, and the IPM and tricaprin were the most stable with shelf lives of 8.25 and 8.86 years, respectively.

New Ultraviolet Spectrophotometric Method for the Estimation of Nimesulide

Two simple and accurate ultraviolet (UV) spectrophotometric methods with better detection range for estimation of nimesulide in pure form and in solid dosage form were developed in the present studies using 50% v/v and 100% v/v acetonitrile as the solvent system. The linearity range of nimesulide in both the methods was found to be 10–50 μg/ml at a λmax of 300 nm. The linear regression equations obtained by the least-square regression method are Abs = 1.33 × 10−1. Conc + 1.89 × 10−1 in 50% v/v acetonitrile and Abs = 1.05 × 10−1. Conc + 1.14 × 10−1 in 100% v/v acetonitrile. The detection limit as per the error propagation theory was found to be 0.46 μg/ml and 1.04 μg/ml, respectively, in 50% v/v and 100% v/v acetonitrile. The developed methods were employed with high degree of precision and accuracy for the estimation of total drug content in three commercial tablet formulations of nimesulide. The results of the analysis were validated statistically and by recovery studies.