Application of Gas Chromatography for the Analysis of Residual Solvents in Transdermal Drug Delivery Systems (TDS)

Background: Transdermal drug delivery systems (TDS) are widely used to deliver a number of different drug therapeutics. The design delivery can be impacted by excipients and, more broadly, organic solvents. Organic or residual solvents are routinely monitored due to safety concerns. However, there is little information on the mechanical properties and delivery performance of TDS. Objective: The objective of this study was to develop and validate an efficient GC-Headspace method to determine the residual solvents (n-heptane, o-xylene, and ethyl acetate) in transdermal patches. The analytical method was applied to monitor residual solvents in TDS and evaluate the potential effect of the residual solvent levels on the TDS adhesion properties. Methods: An Agilent GC 7890A was integrated with an Agilent headspace analyzer 7697A system and was used for method development, analytical method validation, and the testing phases of the study. For the analysis of residual solvents in TDS, 2cm x 3cm, a TDS sample was placed in a 20 mL Headspace vial containing 2 mL of a DMSO/water (1:1, v/v) solvent mixture, and an external standard (cyclohexane) was extracted by the headspace analyzer. The system suitability test was conducted according to USP <621>, and analytical method validation was conducted according to USP <1225> over 3 days for validation and was also performed during in-study sample analysis. Results: The resolution between the solvents was acceptable (2.5, %RSD = 8.0). Intra- and inter-day accuracy and precision of all quality control standards as well as the spiked standards in the transdermal patches were found to be acceptable with RSD% ≤ 10% and accuracy ≥ 85%, respectively. Linearity was > 0.99 for all analytes. Conclusion: The validated GC-Headspace method was successfully applied to a pilot study for in-house manufactured TDS patches to study the impact of residual solvent concentration on adhesion performance.

Formulation and development of Serratiopeptidase enteric coated tablets and analytical method validation by UV Spectroscopy

Serratiopeptidase (SRP) is a proteolytic enzyme that emerged as one of the most potent anti-inflammatory and analgesic drugs. The purpose of the present study was to formulate and evaluate enteric-coated tablets for SRP and investigate their stability using a simple and validated analytical method by ultraviolet (UV) spectroscopy. The colloidal silicon dioxide (2.50%), sodium starch glycolate (3.44%), and crospovidone (2.50%) were used as appropriate excipients for the development of core part of tablets. To protect the prepared tablets from acidic environment in the stomach, white shellac, castor oil, HPMC phthalate 40, and ethyl cellulose were used. The seal coating and enteric coating attained were 2.75% and 6.74%, respectively. SRP was found to be linear at 265 nm in the concentration range of 25–150 µg/mL. The results revealed that our developed method was linear (R2 = 0.999), precise (RSD % = 0.133), and accurate (% recovery = 99.96–103.34). The formulated SRP tablets were found to be stable under accelerated conditions as well as under room temperature for 6 months (assay %: >97.5%). The in vitro drug release study demonstrated that enteric-coated tablets were able to restrict SRP release in both acidic environments: 0.1 N HCl and simulated gastric fluid (pH 1.2). Moreover, at 60 minutes, the formulated SRP tablets revealed 13.0% and 8.98% higher drug release in phosphate buffer (pH 6.8) and simulated intestinal fluid (pH 6.8), respectively, compared to the marketed tablet formulation. This study concludes that enteric-coated tablets of SRP with higher drug release in the intestine can be prepared and examined for their stability using validated analytical technique of UV spectroscopy.

Analytical method validation for related substances in sodium valproate oral solution by gas chromatography

Background Sodium Valproate is the sodium salt of valproic acid (VPA). Valproic acid is mainly used for the treatment of epilepsy. The specific aim of the study is to develop and validate an optimized method for the determination of six related substances such as N,N-dimethyl valpronamide, valeric acid, 2-methyl valeric acid, 2-ethyl valeric acid, 2-isopropyl valeric acid and 2-n-butyl valeric acid in Sodium Valproate Oral Solution by Gas Chromatography. Chromatographic separations of these six related substances were achieved on DB-FFAP fused silica capillary column (30 m × 0.53 mm) bonded with a 0.5-µm layer of macrogol 20,000 2-nitroterephthalate materials used as stationary phase. The six related impurities were extracted using heptane and monitored by Gas Chromatography coupled with flame ionization detector. The performance of the developed method was assessed by evaluating system suitability, method precision, specificity, linearity and range, ruggedness, accuracy, robustness. Results The correlation coefficient was within the acceptance criteria in the range of 0.9998. The evaluated concentrations for Sodium Valproate were in the ranges of 5.05–25.27 ppm. The average recovery values were in the range of 92.4–100.4%. Solution Stability experiments were performed to evaluate the degradation behavior of SVS. Conclusion A novel, precise and sensitive GC method was developed, validated and optimized for the determination of six related substances in sodium Valproate oral solution. The results obtained from the validation experiments demonstrated that the method is accurate, precise, linear, specific, sensitive and robust. Hence, the proposed method can be an alternative method, for the determination of related substances in sodium valproate oral solution drug substance.

Effectively utilizing the Sponsor Contract Research Organization interaction for successful implementation of critical flow cytometry in the clinic

As the number of therapeutic modalities expand, and the field of scientific research evolves toward finding treatment solutions for complex and rare disease, an ability to demonstrate efficacy through biomarker end points in clinical development studies is becoming increasingly important. Implementing flow cytometry in a clinical setting is challenging and many sponsor organizations take a hybrid approach, developing complex analytical methods internally before identifying and forming partnerships with contract research organizations to conduct the formal analytical method validation and sample bioanalysis. Ensuring that these interactions are effective is critical to the delivery of high-quality, impactful clinical data. This paper provides a review of the recommendations, challenges and solutions for the implementation of decision-making flow cytometry end points effectively utilizing the Sponsor Contract Research Organization interaction.

Analytical method validation for biomarkers as a drug development tool: points to consider

Biomarkers are an important drug developmental tool. Assessment of quantitative analytical methods of biomarkers is not included in any regulatory documents in Japan. Use of biomarkers in clinical evaluations and supporting the post-marketing evaluation of drug efficacy and/or adverse reactions requires assessment and full validation of analytical methods for these biomarkers. The Biomarker Analytical Method Validation Study Group is a research group in Japan comprising industry and regulatory experts. Group members discussed and prepared this ‘points to consider document’ covering measurements of endogenous metabolites/peptides/proteins by ligand binding assays and chromatographic methods with or without mass spectrometry. We hope this document contributes to the global harmonization of biomarker assay validation.

Separation and Simultaneous Quantitation of Tolterodine Tartrate and Tamsulosin Hydrochloride in Capsule Formulation by using Stability-Indicating RP-HPLC-DAD Method

In the present work, a precise, accurate and selective stability-indicating RP-HPLC method has been developed and validated according to International Conference on Harmonization guidelines Q2-(R1) for the simultaneous quantitative determination of Tolterodine tartrate and Tamsulosin hydrochloride in bulk and its capsule formulation. The chromatographic separation was achieved on Hypersil octadecyl silane C18 (250 x 4.6mm, 5 μm) column at room temperature and mobile phase comprised of methanol: 0.05 M phosphate buffer, pH 7.0 in the ratio of 90:10 V/V. The flow rate of mobile phase was set at 1.0mL/min and compounds were monitored at 255nm using photodiode array detector. Tamsulosin hydrochloride and Tolterodine tartrate retention time were found to be 4.15±0.2 min and 8.42±0.2 min, respectively. The drug substances and products were subjected to acid hydrolysis, alkali hydrolysis, oxidative hydrolysis, photolytic and thermal degradation. The percent degradation of drugs was calculated in all stressed conditions. The analytical method validation parameters such as linearity, accuracy, precision, detection limits, quantitation limits and robustness indicate that drug substances and products were efficiently separated in present of their degradants and successfully applied for the routine analysis of Tolterodine tartrate and Tamsulosin hydrochloride in bulk and its capsule formulation in the quality control laboratory.

ANALYTICAL METHOD VALIDATION, PHARMACOKINETICS AND BIOEQUIVALENCE STUDY OF DIMETHYL FUMARATE IN HEALTHY IRANIAN VOLUNTEERS

Objective: Pharmacokinetic evaluation of Dimethyl Fumarate (DMF) in the Iranian population wasn’t studied. So, the aim of this research is the validation of the analytical method and evaluation of the pharmacokinetic properties and bioequivalence of the generic form of this drug versus the reference product. Methods: 2 single-dose, test, and reference DMF products were orally administered to 24 healthy volunteers. The washout period was 28 d between the treatments. Monomethyl fumarate as the metabolite of DMF was analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and the method was validated. Also, the pharmacokinetic parameters were calculated for bioequivalence evaluation. Results: The analytical method was validated and linear over the range of 31.25-4000 ng/ml (R2= 0.997). In addition, the method was precise and accurate in the low, medium, and high concentrations. The results indicated that the 2 products had similar pharmacokinetics. Further, the 90% CI of the mean ratios of the test versus the reference products of the log-transformed area under the concentration-time curve over 10 h (0.99 to 1.02) and peak concentration (0.98 to 1.03) were within the acceptable range of 0.8 to 1.25 and the generic product of DMF could be similar to that of the reference product. Conclusion: The applied analytical method is selective, accurate, precise, and repeatable for the analysis of monomethyl fumarate (MMF) in plasma. Also, the bioequivalence study showed no significant difference between the pharmacokinetic parameters of these 2 products. So, the DMF test product can be claimed to be bioequivalent with the reference product.

Analytical Method Validation and Quantitative Analysis for Active Pharmaceutical Ingredient and Marketed Formulation of Teneligliptin Hydrobromide by UV Spectroscopy

A Dipeptidyl peptidase-4 inhibitor teneligliptin hydrobromide is used for lowering blood glucose levels in people with diabetes mellitus. A very straight forward, quick, responsive and accurate UV- Spectrophotometric method of analysis have been developed for assessment of Teneligliptin Hydrobromide in pharmaceutical formulation. Since teneligliptin hydrobromide only absorbs UV in the low wavelength area, it cannot be identify with high sensitivity. Teneligliptin Hydrobromide has shown successful results for various analytical instruments only in the permutation of Taurine and Sodium periodate. The API was derivatives using Taurine and Sodium periodate in water and methanol. Drug exhibited distinct λmax in methanol at 281nm. Linearity was observed in the concentration range 10-80 μg/ml. The method was validated by recovery studies. The methods used are inexpensive and sensitive for the inference of teneligliptin hydrobromide in bulk drug and tablet dosage forms.

Analytical Method Validation and Formula Optimization of Topical Nanoemulsion Formulation Containing Resveratrol

Resveratrol (RSV), a natural lipophilic phytoalexin, was reported as an antioxidant and anti-inflammatory agent, which has the potential to cure diabetic wounds. However, several studies suggested the limitation of RSV, such as poor aqueous solubility, poor stability, and poor oral bioavailability. To overcome the issues, RSV was formulated as a topical nanoemulsion. It is important to ensure the quality of the dosage form by evaluating RSV load in the nanoformulation and optimizing the formula. A reversed-phase HPLC method was developed and validated prior to the load determination of RSV in the nanoemulsion formulation. The composition of triacetin-eugenol, Kolliphor® RH 40, and Transcutol® was further optimized by employing a Box-Behnken Design (BBD) to achieve the optimum composition with expected viscosity and RSV load. The HPLC method for determining RSV load was successfully validated for parameters of selectivity with the resolution of 8.487, linearity and range (r = 0.9979), precision (0.12% of RSD), accuracy (109–110% of recovery), the limit of detection (0.574 µg/mL), and limit of quantitation (1.740 µg/mL). The result of formula optimization was promising, showing the optimum composition of triacetin-eugenol, Kolliphor® RH 40, and Transcutol® at 4.44 g, 30.97 g, and 11.39 g, respectively.