Date of Completion

2025

Document Type

Thesis

Degree Name

Bachelor of Science in Pharmacy

Keywords

MLCE, Preservative, Antacid Oral Suspension, Compatibility Testing, Antimicrobial Effectiveness Testing

Abstract

This study explored the potential of Malunggay (Moringa oleifera) leaves crude extract (MLCE) as a natural preservative in antacid oral suspensions (AOS), given concerns about synthetic preservatives and widespread antacid use. The study aimed to assess the preservative activity of MLCE in an AOS formulation. MLCE was prepared from oven-dried leaves, ensuring low moisture content (6.05–6.74%), through 95% ethanol maceration. The extract’s total phenolic content (TPC) was confirmed and quantified, with one sample showing 95.53 mg GAE/g. Using the DPPH assay, the antioxidant activity of MLCE was evaluated, yielding an IC₅₀ value of 24.03 mg/mL. Based on established criteria, this corresponds to an IC₅₀ greater than 0.5 mg/mL, classifying MLCE as an inactive antioxidant. Compatibility testing revealed no major physical changes, though MLCE’s hygroscopic nature—especially when combined with certain excipients like citric acid and fumed silica—led to some clumping and liquefaction; therefore, citric acid was removed from the formulation. Seven (7) AOS formulations were then developed: one without preservatives (NA), one with MLCE only (ML), two with MLCE combined with either methylparaben (MML) or propylparaben (PML), and positive controls with propylparaben only (P), methylparaben only (M), and both methylparaben and propylparaben (MP). Accelerated stability testing was also conducted to simulate long-term environmental effects on the formulations. On Day 0, all samples were reconstitutable after shaking. However, after one month of storage at elevated room temperature, all formulations exhibited clumping and could no longer be easily redispersed, though no changes in color were observed. Despite initial excipient compatibility, the formulations demonstrated instability under stressed conditions. For antimicrobial effectiveness testing (AET), following USP < 51> guidelines with modifications, the formulations were challenged with Escherichia coli, Candida albicans, and Aspergillus niger. The results showed that MLCE, whether used alone or in combination, was ineffective in inhibiting microbial growth, indicating it is not a viable standalone preservative for AOS.

First Advisor

Renz Angelo G. Bunquin, RPh

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