Variables Affecting Delivery of Glycopyrronium Tosylate Through Human Skin In Vitro.

BACKGROUND: Hyperhidrosis is a condition characterized by excessive sweating beyond what is required for normal thermal regulation. It can involve multiple body areas including the axillae, palms, soles, or craniofacial regions. Glycopyrronium tosylate (GT) is a topical anticholinergic approved by the FDA (2018) for treatment of primary axillary hyperhidrosis in patients 9 years and older. OBJECTIVE: Gain insight into variables (anatomical sites, occlusion, exposure time) affecting GT delivery into human skin. METHODS: Human skin from different anatomical regions (palmar, plantar, axillary, and abdominal skin) was mounted into flow-through diffusion cells (MedFlux-HT®). GT solution (2.4%) was applied at 10 mg/cm2 and the receiving fluid was collected every 2 hours, for 24 hours. GT penetration was determined using LC/MS/MS. The effect of occlusion was assessed by covering the skin with either parafilm or saran wrap, and the effect of exposure time was assessed by incubating the skin for 5, 15, or 60 minutes before washing off the GT from the surface. RESULTS: GT delivery through palmar and plantar skin was up to 40-fold lower compared to delivery through axillary or abdominal skin. Occlusion increased GT delivery up to 10-fold. Reducing exposure time from 24 hours to either 5, 15, or 60 minutes, decreased GT flux by 90%. However, occlusion during these varied exposure times was able to restore GT delivery to levels found in the 24-hour exposed, non-occluded control group. CONCLUSION: These in vitro skin penetration studies showed that skin thickness, exposure time, and occlusion substantially influenced GT delivery, potentially impacting clinical trial design. J Drugs Dermatol. 2020;19(11): doi:10.36849/JDD.2020.5062.

HPTLC Method for Determination of R, R-Glycopyrronium Bromide and its Related Impurities.

An innovative high-performance thin layer chromatographic (HPTLC) method was designed, optimized and validated for the quantification of R, R-glycopyrronium bromide (GLY) and its related impurities in drug substance and drug product. Separation was performed on HPTLC plates pre-coated with silica gel 60 F254 by dichloromethane:methanol:formic acid (10:0.5:0.5, v/v/v) as a developing system. GLY and its related impurities namely, glycopyrronium impurity G and glycopyrronium impurity J, were separated giving compact well-resolved spots with significant retardation factor (Rf) values of 0.17 ± 0.02, 0.34 ± 0.02 and 0.69 ± 0.02, respectively. Quantification was done at 220 nm in the ranges of 0.3-10 and 0.2-4.0 µg/spot with limits of detection and quantification of 0.1, 0.3 and 0.05, 0.2 µg/spot for GLY and its related impurities, respectively. Good accuracy was obtained with mean percentage recovery of 99.48 ± 1.36, 100.04 ± 1.32 and 99.61 ± 0.80 and R2 ≥ 0.9968 for GLY and its impurities, consecutively. Validation parameters were presented according to the International Conference on Harmonization. The method was used to investigate impurity profile of GLY in drug substance and drug product and could be applied in routine analysis of the drug. Comparison between the developed method and the reported method revealed no statistical difference.

Validated ion pair chromatographic method for simultaneous determination and in vitro dissolution studies of indacaterol and glycopyrronium from inhaled capsule dosage form.

A rapid, and highly sensitive analytical method were developed for the simultaneous determination of indacaterol maleate (IND) and glycopyrronium bromide (GLY) in their inhaler capsules. Valid ion-pairing chromatographic (IPC) method was performed for separation of GLY in presence of IND using C18 column and mobile phase consisting of acetonitrile: acidified deionized water (60:40% v/v) containing 0.02% sodium dodecyl sulfate (SDS) adjusted to pH 3.0 using OPA (orthophosphoric acid) isocratically eluted at 2.0 mL/min. Quantitation was achieved with UV detection at 210 nm. Cyproheptadine was used as an internal standard. The retention times were 1.9 and 2.5 min for IND, and GLY, respectively. For the IPC method, the calibration graphs were linear in the range of 0.66-66.0 µg/mL for IND and 0.3-30.0 µg/mL for GLY. The proposed method are rapid, reproducible (R.S.D. <2.0%) and achieves satisfactory resolution between IND and GLY (resolution factor = 4.23). The mean recoveries of the analytes in their inhaler capsule were satisfactory. It was applied successfully to in vitro dissolution testing using Franz diffusion cell and extended to a content uniformity test consistent with the United States Pharmacopoeia (USP) guidelines and were found to be precise and accurate for the capsules studied with acceptance value of 4.53 and 1.39 for IND and GLY, respectively.

Simultaneous spectrophotometric determination of indacaterol and glycopyrronium in a newly approved pharmaceutical formulation using different signal processing techniques of ratio spectra.

Three spectrophotometric methods have been developed and validated for determination of indacaterol (IND) and glycopyrronium (GLY) in their binary mixtures and novel pharmaceutical dosage form. The proposed methods are considered to be the first methods to determine the investigated drugs simultaneously. The developed methods are based on different signal processing techniques of ratio spectra namely; Numerical Differentiation (ND), Savitsky-Golay (SG) and Fourier Transform (FT). The developed methods showed linearity over concentration range 1-30 and 10-35 (µg/mL) for IND and GLY, respectively. The accuracy calculated as percentage recoveries were in the range of 99.00%-100.49% with low value of RSD% (<1.5%) demonstrating an excellent accuracy of the proposed methods. The developed methods were proved to be specific, sensitive and precise for quality control of the investigated drugs in their pharmaceutical dosage form without the need for any separation process.

Isothermal microcalorimetry of pressurized systems II: effect of excipient and water ingress on formulation stability of amorphous glycopyrrolate.

PURPOSE: Use isothermal microcalorimetry to directly evaluate the effects of excipients and water content to produce a stable amorphous glycopyrrolate pressurized metered dose inhaler (pMDI) formulation. METHODS: Amorphous glycopyrrolate particles with and without excipients (Distearoyl-sn-glycero-3-phosphatidylcholine (DSPC) or ß-cyclodextrin (ßCD)) were spray dried and cold filled along with HFA 134a into customized thermal activity monitor (TAM) measurement ampoules. When applicable, a known amount of water was also pipetted into the ampoule. Sample ampoules were hermetically sealed, equilibrated to 25°C and measured isothermally for at least 24 h using the TAM III (TA Instruments, Sollentuna, Sweden). RESULTS: Amorphous glycopyrrolate particles were highly unstable and crystallized rapidly when suspended in HFA 134a. Co-spray drying the glycopyrrolate with DSPC failed to mitigate this instability, but co-spray drying with ßCD protected the amorphous glycopyrrolate from crystallization, resulting in a stable formulation at low water contents (≤ 100 ppm). CONCLUSIONS: This study shows that isothermal microcalorimetry can easily differentiate between physically stable and unstable pMDI formulations of glycopyrrolate within a few hours. Furthermore, it allows rapid screening of various formulation factors (drug form, excipients, water ingress), which can greatly reduce the time required to develop marketable products with acceptable shelf life.

Determination of the enantiomeric and diastereomeric impurities of RS-glycopyrrolate by capillary electrophoresis using sulfated-ß-cyclodextrin as chiral selectors.

A practical chiral CE method, using sulfated-ß-CD as chiral selector, was developed for the enantioseparation of glycopyrrolate containing two chiral centers. Several parameters affecting the separation were studied, including the nature and concentration of the chiral selectors, BGE pH, buffer type and concentration, separation voltage, and temperature. The separation was carried out in an uncoated fused-silica capillary of (effective length 40 cm) × 50 µm id with a separation voltage of 20 kV using 30 mM sodium phosphate buffer (pH 7.0, adjusted with 1 M sodium hydroxide) containing 2.0% w/v sulfated-ß-CD at 25°C. Finally, the method for determining the enantiomeric impurities of RS-glycopyrrolate was proposed. The method was further validated with respect to its specificity, linearity range, accuracy and precision, LODs, and quantification in the expected range of occurrence for the isomeric impurities (0.1%).

Determination of (R,R)-glycopyrronium bromide and its related impurities by ion-pair HPLC.

A simple, rapid and specific ion-pair HPLC method for the determination of (R,R)-glycopyrronium bromide and its related impurities is presented, and parameters affecting the chromatographic properties of these compounds are discussed. Optimal analyte separation was achieved on base deactivated Nucleosil at 40 degrees C, using phosphate buffer pH 2.30 with sodium-1-decanesulfonate (0.01 M)/methanol (35/65; v/v) as eluent for isocratic elution at a flow rate 1 ml x min(-1). The analytical assay was validated according to international guidelines. The methodis suitable for in-process control and as stability indicating assay.

Stability of buprenorphine, haloperidol and glycopyrrolate mixture in a 0.9% sodium chloride solution.

Combinations of opioids and adjuvant drug solutions are often used in clinical practice while little information is available on their microbiological or chemical stability. Currently there are no commercially available, prepacked, ready-to-use epidural or subcutaneous mixtures. Thus, epidural and subcutaneous analgesic mixtures must be prepared in the pharmacy on an as-needed basis. Such mixtures are typically used for the treatment of severe pain in cancer patients. The aim of this study was to investigate the microbiological and chemical stability of a buprenorphine, haloperidol and glycopyrrolate mixture in a 0.9% sodium chloride solution. A high performance liquid chromatographic (HPLC) method and pH-meter were used to conduct the analyses. Antimicrobial activity of each component was studied by an agar dilution method. According to the results from the chemical and microbiological stability studies, this mixture can be stored in polypropylene (PP) syringes and polyvinyl chloride (PVC) medication cassettes for at least 30 days at either 21 degrees C or 4 degrees C, and for 16 days in PP syringes at 36 degrees C, and for 9 days in PVC medication cassettes at 36 degrees C.

Analysis of some antispasmodic drugs: oxyphencyclimine and glycopyrronium bromide.

Oxyphencyclimine hydrochloride (via its tertiary amine group) and glycopyrronium bromide (via its quaternary ammonium group) were analysed by two different colorimetric methods. The first method depends on the dye-salt formation method using tropeolin ooo as the anionic dye and 1,2-dichloroethane as solvent for the extraction of the formed ion pairs. The coloured ion pairs have maximum absorption at 483-486 nm. The second method is based on the use of citric acid-acetic anhydride reagent. The coloured complex has maximum absorption at 562-565 nm.