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.

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.

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.