Study to Evaluate the Effects of Oral Glyceryl Guiacolate (Guaifenesin, GGE) on Sputum Rheology in Subjects With Mucus Hypersecretion

The objective is to confirm GGE's impact on transforming mucus to optimal form that facilitates its loosening from airway walls and improves mucociliary clearance. The investigators propose a standard of care (SOC defined as all current medications prescription and non-prescription drugs and supplements) controlled clinical trial involving 40 participants (20 GGE / 20 SOC) with stable chronic bronchitis ((defined as subjects with chronic productive cough that occurs daily for at least 3 months in 2 consecutive years, in a patient who has not had an acute exacerbation within the previous 4 weeks; where an acute exacerbation of chronic bronchitis is defined as an acute worsening of a patient's symptoms, beyond normal day-to-day variations, necessitating a change in treatment with antibiotics and/or corticosteroids)). The trial will collect sputum samples before (baseline) and after 14 \& 28 days of daily GGE/SOC administration and assess rheological properties to quantify changes in sputum viscosity, elasticity, and flow properties. These measurements will be evaluated to elucidate whether GGE reduces mucus rigidity and adhesiveness, facilitating clearance by cilia and coughing, while providing insights into its molecular and physiological effects. Mucus plugging will be assessed by CT lung imaging to determine if lung imaging could act as an outcome measure of the effect of GGE/SOC. This integrated approach aims to advance understanding of outcomes to assess GGE's therapeutic potential and guide future research for respiratory diseases characterized by thickened mucus.

• Glycerol Guiacolate (Drug), also known as Mucinex: Participants will receive 28 days (+3 days for flexible scheduling) dosing of Glycerol Guiacolate (GGE) (2 x 600 mg for a total of 1200mg) taken twice daily (total of 2400 mg) in addition to current medications.
• SOC (Standard of care) (Drug): Current medication excluding mucolytics or steroids

Primary outcomes

• Change in mucus viscosity [Baseline to end of treatment (Day 28)]: measurement of mucus viscosity
• Change in mucus elasticity [Baseline to end of treatment (Day 28)]: measurement of mucus elasticity
• Change in mucus concentration [Baseline to end of treatment (Day 28)]: measurement of mucus concentration

Secondary outcomes

• CT Quantitation of airway mucus plugs [Baseline to day 28.]: Change in mucus plug score from baseline to day 28. Segments will be scored as 0 (absent) or 1 (present) for mucus plugs. A total segment score ranging from 0 to 18 for each patient will be calculated. A decrease in the mucus plug score reflects a beneficial finding.

Sex: All, ages: 40 Years to 75 Years

Inclusion Criteria:

* • Confirmed diagnosis of stable chronic bronchitis (defined as subjects with chronic productive cough that occurs daily for at least 3 months in 2 consecutive years, in a patient who has not had an acute exacerbation within the previous 4 weeks; where an acute exacerbation of chronic bronchitis is defined as an acute worsening of a patient's symptoms, beyond normal day-to-day variations, necessitating a change in treatment with antibiotics and/or corticosteroids).

  * Ability to produce spontaneous sputum and non-reactive to hypertonic saline for induced sputum collection.
  * Stable disease (no exacerbations requiring hospitalization in the past 28 days).
  * A Pulmonary Function Test with Forced Expiratory Volume in 1st second (FEV1) FEV1/Forced Vital Capacity (FVC) less than 0.7 (70%) but greater than 0.4 (40%) at the time of enrollment and at least a 10-year history of cigarette use.
  * Participants who have not used guaifenesin-containing products within one month of the time of study enrollment.
  * Adults age 40-75 with stable chronic bronchitis with persistent cough.

Exclusion Criteria:

* • Current use of mucolytics (e.g., N-acetylcysteine), corticosteroids, or other GGEs known to alter mucus properties.

  * Severe comorbidities (e.g., Gastroesophageal Reflux Disease (GERD), heart failure, advanced Chronic Obstructive Pulmonary Disease (COPD,) or cystic fibrosis).
  * Smokers (within the past year). Note: Participants with a positive cotinine test at the baseline visit will be dropped from the study.
  * Recent viral infection or other pulmonary exacerbation (< 1 month).
  * Participants who are pregnant or breastfeeding.
  * Pulmonary diagnosis other than Chronic Bronchitis (CB) (such as cystic fibrosis, alpha-1 antitrypsin deficiency, bronchiectasis, or pulmonary fibrosis) or active lung cancer.
  * Participation in another study involving an investigational product within 30 days of the baseline visit.
  * Known allergy to the study GGE or its components.
  * History of alcohol and/or drug abuse within one year of study start.
  * Participants taking intermittent antibiotics and participants taking oral and systemic corticosteroids (e.g., prednisone at a dose of > 10 mg/day). (Note: Participants on a chronic stable dose of macrolide antibiotics at the start of the study may be included at the discretion of the Principal Investigator.)
  * Participants who had an acute exacerbation of chronic bronchitis within one month of starting the study that required systemic steroids or antibiotics.
  * Hypersensitivity to hypertonic saline, guaifenesin, or any other excipient listed in the product.
  * Inability to provide informed consent.

• Brian Button, PhD, Principal investigator, University of North Carolina, Chapel Hill