DEVELOPMENT AND VALIDATION OF RP-HPLC METHOD FOR SIMULTANEOUS ESTIMATION OF DICLOFENAC DIETHYLAMINE AND CURCUMIN IN TRANSDERMAL GELS

Development of an RP-HPLC Method for Quantifying Diclofenac Diethylamine, Methyl Salicylate, and Capsaicin in Pharmaceutical Formulation and Skin Samples

An RP-HPLC method with a UV detector was developed for the simultaneous quantification of diclofenac diethylamine, methyl salicylate, and capsaicin in a pharmaceutical formulation and rabbit skin samples. The separation was achieved using a Thermo Scientific ACCLAIMTM 120 C18 column (Waltham, MA, USA, 4.6 mm × 150 mm, 5 µm). The optimized elution phase consisted of deionized water adjusted to pH = 3 using phosphoric acid mixed with acetonitrile in a 35:65% (v/v) ratio with isocratic elution. The flow rate was set at 0.7 mL/min, and the detection was performed at 205 nm and 25 °C. The method exhibits good linearity for capsaicin (0.05-70.0 µg/mL), methyl salicylate (0.05-100.0 µg/mL), and diclofenac diethylamine (0.05-100.0 µg/mL), with low LOD values (0.0249, 0.0271, and 0.0038 for capsaicin, methyl salicylate, and diclofenac diethylamine, respectively). The RSD% values were below 3.0%, indicating good precision. The overall greenness score of the method was 0.61, reflecting its environmentally friendly nature. The developed RP-HPLC method was successfully applied to analyze Omni Hot Gel® pharmaceutical formulation and rabbit skin permeation samples.

Rapid Analytical Method Development and Validation of RP-HPLC Method for the Simultaneous Estimation of Exemestane and Genistein with Specific Application in Lipid-Based Nanoformulations

Exemestane (EXE), an irreversible aromatase inhibitor, is employed as a therapy for hormone-dependent breast cancer. Several studies have also established the budding effects of genistein (GEN) in various types of cancer such as breast, prostate, as well as skin due to its feeble estrogenic and anti-estrogenic properties. Considering the promising benefits of GEN, it was combined with EXE to accomplish superior therapeutic efficiency with fewer side effects. The quantification of the exact concentration of EXE and GEN when delivered as a combination would be required for which HPLC method was developed and validated. For this purpose, the C18 ODS column having dimensions of 150 × 4.6 mm, 5 μm, using mobile phase A as methanol:water (35:15, v/v), with formic acid (0.01%), and B as acetonitrile (in the ratio of A:B--30:70 v/v) at a flow rate of 1 mL/min was commonly used. The Box-Behnken design was chosen as our experimental model, and the interactions among the independent and dependent variables were analyzed. Parameters like linearity, system suitability, specificity, precision (intra- and interday), robustness, ruggedness, LOD (limit of detection), and LOQ (limit of quantification) were selected for the validation of our proposed method. EXE and GEN were eluted individually at 245 and 270.5 nm, respectively, while both of the agents were determined simultaneously at 256 nm, showing retention time as 2.10 and 1.67 min, respectively, and the calibration plot was observed to be linear in the range of 5-110 μg/mL. Hence, the method that we developed and validated was found to be suitable for the identification of both the drugs simultaneously in combination and in our in-house-developed nanoformulation.

Sublimation of Drugs from the Site of Application of Topical Products

The objective of the project was to investigate the plausibility of active pharmaceutical ingredients (APIs) to undergo sublimation from topical application following evaporation of solvent. Topical formulations with different APIs were subjected to a sublimation screening test. The APIs in the selected topical products were found to undergo sublimation to a different extent. The salicylic acid topical product was found to undergo a significant loss due to sublimation. The extent of sublimation of salicylic acid was significantly greater at skin temperature compared to room temperature. When the APIs were subjected to the sublimation screening test in their neat form at 32 ± 1 °C, the natural log of the rate of sublimation decreased linearly with the standard enthalpy of sublimation of compound (R² = 0.89). The formulation composition was found to have a significant impact on the extent of sublimation of the representative API, salicylic acid. The sublimation of APIs from the topical product was found to affect the mass balance studies in the case of the salicylic acid ointment. Furthermore, the results of the human studies agreed with the in vitro experimental results demonstrating the plausibility of loss of API due to sublimation from the site of application.

A novel stability-indicating UPLC method development and validation for the determination of seven impurities in various diclofenac pharmaceutical dosage forms

An innovative simple, fast, precise and accurate ultra-high performance liquid chromatography (UPLC) method was developed for the determination of diclofenac (Dic) along with its impurities including the new dimer impurity in various pharmaceutical dosage forms. An Acquity HSS T3 (C18, 100×2.1mm, 1.8μm) column in gradient mode was used with mobile phase comprising of phosphoric acid, which has a pH value of 2.3 and methanol. The flow rate and the injection volume were set at 0.35ml·min(-1) and 1μl, respectively, and the UV detection was carried out at 254nm by using photodiode array detector. Dic was subjected to stress conditions from acid, base, hydrolytic, thermal, oxidative and photolytic degradation. The new developed method was successfully validated in accordance to the International Conference on Harmonization (ICH) guidelines with respect to specificity, limit of detection, limit of quantitation, precision, linearity, accuracy and robustness. The degradation products were well resolved from main peak and its seven impurities, proving the specificity power of the method. The method showed good linearity with consistent recoveries for Dic content and its impurities. The relative percentage of standard deviation obtained for the repeatability and intermediate precision experiments was less than 3% and LOQ was less than 0.5μg·ml(-1) for all compounds. The new proposed method was found to be accurate, precise, specific, linear and robust. In addition, the method was successfully applied for the assay determination of Dic and its impurities in the several pharmaceutical dosage forms.

Manipulating ratio spectra for the spectrophotometric analysis of diclofenac sodium and pantoprazole sodium in laboratory mixtures and tablet formulation

Objective. Three sensitive, selective, and precise spectrophotometric methods based on manipulation of ratio spectra, have been developed and validated for the determination of diclofenac sodium and pantoprazole sodium. Materials and Methods. The first method is based on ratio spectra peak to peak measurement using the amplitudes at 251 and 318 nm; the second method involves the first derivative of the ratio spectra (Δλ = 4 nm) using the peak amplitudes at 326.0 nm for diclofenac sodium and 337.0 nm for pantoprazole sodium. The third is the method of mean centering of ratio spectra using the values at 318.0 nm for both the analytes. Results. All the three methods were linear over the concentration range of 2.0–24.0 μg/mL for diclofenac sodium and 2.0–20.0 μg/mL for pantoprazole sodium. The methods were validated according to the ICH guidelines and accuracy, precision, repeatability, and robustness are found to be within the acceptable limit. The results of single factor ANOVA analysis indicated that there is no significant difference among the developed methods. Conclusions. The developed methods provided simple resolution of this binary combination from laboratory mixtures and pharmaceutical preparations and can be conveniently adopted for routine quality control analysis.

A novel nano-carrier transdermal gel against inflammation

The objective was to develop a stable, reproducible and patient non-infringing novel transdermal drug delivery system "nano-carrier transdermal gel" (NCTG) in combination of partial dose replacement of diclofenac diethylamine (DDEA) by curcumin (CRM). The drug content of gel was 99.30 and 97.57% for DDEA and CRM. Plasma samples were analyzed by liquid chromatography with triple-quadrupole tandem mass spectrometer (LC-MS/MS). Data were integrated with Analyst™ and analyzed by WinNonlin; stability parameters were analyzed using Tukey-Kramer multiple comparison test. Its average skin irritation scored 0.49 concluded to be non-irritant, safe for human use and in vivo studies revealed significantly greater extent of absorption and highly significant inhibition (%) of carrageenan induced paw edema. The results also demonstrated that encapsulation of drugs in nano-carrier increases its biological activity due to superior skin penetration potential. Hence, a novel once day transdermal gel of nano-carrier (nano-transfersomes; deformable vesicular) is achieved, to increase systemic availability, subsequent reduction in dose and toxicity of DDEA was developed for the treatment of inflammation.