BACKGROUND AND OBJECTIVES

Staphylococcus aureus poses a significant public health threat globally, where both community and hospital-acquired infections are prevalent. The escalating antimicrobial resistance highlights the urgent need for alternative therapies. Hence, traditional medicine using plant extracts offers a potential avenue for novel antibacterial agents. This systematic review aimed to evaluate the existing literature on the antibacterial properties of Philippine plants against S. aureus to provide focus on drug development of a plant-derived antibacterial for this pathogen.

Following PRISMA guidelines, a comprehensive search was conducted in PubMed/Medline, SCOPUS, and Herdin databases. Inclusion criteria encompassed in-vitro studies evaluating the antibacterial activity of crude plant extracts sourced from Philippines plants against S. aureus. Data extraction and quality assessment were performed independently by two reviewers, with discrepancies resolved by the third and fourth reviewers.

Of the 413 initial studies identified, nine (9) met the eligibility criteria. The highest zone of inhibition was demonstrated by Lippia micromera L. leaf essential oil at 26.3±1.5 mm, while moderate antibacterial activity was shown by essential oils from Alpinia elegans, Piper quinqueangulatum, and Alpinia cumingii at MIC values of 512 µg/mL, 512 µg/mL, and 1,024 µg/mL, respectively. Other Philippine plants showed a wide range of activity, with MIC values between 50 ?g/mL and 25 mg/mL, MBC values from 78 to 5000 ?g/mL, and ZOI ranging from 5 to 38 mm. However, the overall quality of evidence in these other studies are compromised by bias and incomplete reporting.

Leaf essential oils from Alpinia elegans, Piper quinqueangulatum, and Alpinia cumingii demonstrated moderate antibacterial activity against S. aureus. Additionally, the essential oils of Lippia micromera L., Plectranthus amboinicus Lour. Spreng, and Cymbopogon citratus exhibited antibacterial activity against both S. aureus and Methicillin-resistant S. aureus (MRSA) in disk diffusion assays. Majority of the studies gathered had high risk of bias according to the quality assessment criteria tool used in the study. Thus, this systematic review also emphasizes the need for improved methodological rigor on reported in-vitro antibacterial studies.

OBJECTIVES

In response to the need for a simple and fast way of ensuring that generic drugs especially those that contain rifampicin are bioequivalent with reference drugs, this study validated an ultra-high-performance liquid chromatography (UHPLC) method of quantifying rifampicin in human plasma. The study also validated the method's selectivity, linearity, sensitivity, accuracy, precision, and the absence of a carry-over effect adhering to the Philippine Food and Drug Administration guidelines.

Plasma samples were prepared via protein precipitation using methanol containing ascorbic acid. Three microliters (3 uL) of the prepared samples were then analyzed in a Waters Acquity H-Class UPLC® system coupled to a tunable ultraviolet (TUV) detector with an attached UPLC® BEH C-18 column using a developed and optimized method. Briefly, the column temperature was set to 40°C and the sample temperature was set to 10°C. Elution was done using a linear gradient flow of a water-acetonitrile mixture that started with 45% acetonitrile increasing to 60% acetonitrile at 0.5 minutes and back to 45% acetonitrile at 3 minutes and having a constant flow rate of 0.5 mL/min. Detection was done at 340 nm. Method validation was performed following the ICH guidelines for Bioanalytical Method Validation, the same guidelines referenced by the ASEAN Guideline for Harmonisation of Standards and the Philippine Food and Drug Administration (FDA).

The method had an analysis time of 3 minutes wherein rifampicin eluted at 1.4 minutes while the internal standard, rifapentine (IS) eluted at 1.7 minutes. Since no co-eluting endogenous materials were observed for the rifampicin and the internal standard, the method was confirmed to be selective. Its linearity over the range of 2 ug/mL to 25 ug/mL has been validated where it has a limit of detection (LOD) and limit of quantification (LOQ) values of 0.64 ug/mL and 1.94 ug/mL, respectively. The interday and intraday precision, reported as % coefficient of variance (%CV), and interday and intraday accuracy, reported as %error all within the limits of ±20% for the LLOQ and ±15% for the rest indicating its reliability and reproducibility. Lastly, due to the nature of the injection of the sample into the system, wherein a blank immediately follows the highest concentration standard, the method has been cleared of a carry-over effect.

The study successfully validated a UHPLC method of quantifying rifampicin in human plasma. Due to the sample processing method used and the chromatographic conditions set, the method can prepare and analyze samples in a simple yet fast, sensitive, reliable, and reproducible manner. The method can be applied in bioavailability and bioequivalence studies of rifampicin.

BACKGROUND AND OBJECTIVE

Oral ivermectin is recommended as an alternative to topical permethrin in Japanese, European, and CDC-STI guidelines for treating classic scabies. The combination of oral ivermectin and topical permethrin is also used in some settings. Partial economic evaluations conducted in India and Egypt have conflicting results, and no cost-effectiveness analysis in the Philippines has compared ivermectin-based regimens to permethrin for scabies treatment. We aimed to determine the cost-effectiveness of oral ivermectin, alone or in combination with permethrin, compared to permethrin, in the treatment of Filipino adult patients with classic scabies.

We used a decision tree model to estimate the cost-effectiveness of two regimens, oral ivermectin alone or in combination with permethrin, compared with permethrin to treat adults and children aged five years and older with classic scabies in the outpatient setting from the household perspective in the Philippines. We estimated total costs and disability-adjusted life years (DALYs) over a one-month follow-up. Input parameters were obtained from secondary data, such as effect estimates for probabilities of clinical outcomes from a network meta-analysis, DALYs from the Global Burden of Disease 2019, and prevailing market cost in the Philippines (DPRI 2022 with recommended markup by DOH, and leading drugstores) as of August 2022. We computed for incremental cost-effectiveness ratio (ICER) and net monetary benefit (NMB) to determine which of the interventions are cost-effective. Univariate and probabilistic sensitivity analyses, and scenario analyses were conducted to assess the impact of parameter and structural uncertainty.

Ivermectin-based regimens are suggested to be likely cost-saving compared to permethrin in the Philippine outpatient setting. Base case analysis showed that oral ivermectin had higher cost-savings (change in cost, -1,039.31; change in DALYS, 0.00027), while combination oral ivermectin/permethrin had higher DALYs averted (change in cost, PhP -1,019.78; change in DALYs, 0.00045), compared to permethrin. Combination oral ivermectin/permethrin (56%) was the most cost-effective, followed by oral ivermectin (44%) compared to permethrin (0%) through probabilistic sensitivity analysis. Estimates for ivermectin were sensitive to risk of cure for ivermectin vs permethrin using 1-way deterministic sensitivity analysis. Oral ivermectin was favored over combination oral ivermectin/permethrin at all thresholds based on the cost-effectiveness acceptability curve.

Both ivermectin-based regimens seem to be cost-saving compared to permethrin in the treatment of classic scabies in the Philippine outpatient setting. Clinicians may consider oral ivermectin, alone or in combination with permethrin as an alternative first-line or second-line treatment depending on patient preference, adverse event risk profile, availability, and economic capacity. This needs to be confirmed using primary data from Filipino patients to enhance the robustness of the findings and support evidence-based local decision-making in different settings. Less uncertainty in modelled parameters can give greater confidence in the results, which can be adopted for budget impact analysis and allow more rational resource allocation. Value of information analysis can be done to determine whether the expense of future RCTs or surveys in Filipinos to collect primary data is worth it. The cost of reducing uncertainty, if deemed worth the cost of further studies, may facilitate population-level decision-making and budget planning. Findings may further inform practice guideline development, coverage decisions, and national control program planning by providing the most cost-effective scabies intervention.

BACKGROUND

Drug use and abuse is a public health issue that has come into focus in the Philippines in the past years. Excluding the years of the COVID-19 pandemic, there has been a yearly increase in the number of admissions to treatment and rehabilitation centers. The census in the University of the Philippines-Philippine General Hospital (UP-PGH) National Poison Management and Control Center (NPMCC) shows a parallel increase in drug-positive patients consulting in the emergency room (ER).

The objective of this study was to describe the demographic, clinical, and drug use profiles of substance users admitted to the UP-PGH and referred to the NPMCC for drug testing.

This is a cross-sectional study where participants included patients aged 10 years and above who were referred to the NPMCC for drug testing within three days of the ER consult. Once consent or assent from children was obtained, patients were interviewed and examined. Urine samples were collected for drug screening using drugs of abuse screening test kits. A split sample was sent to the UP Drugs of Abuse Research Laboratory (UP DARL) for analysis using the liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF/MS). The data was encoded in the REDcap platform. The results were analyzed and summarized using descriptive statistics.

Three hundred eighty-four (384) individuals participated in the study and submitted urine samples for testing from 1 January 2019 to 28 February 2020. One hundred thirty-four (134) samples were positive for substances of abuse detected by drug screening test kits for methamphetamine (MAP), delta-9-tetrahydrocannabinol (THC), cocaine, 3,4-methylenedioxymethamphetamine (MDMA), benzodiazepines, and opioids, and by LC-QTOF/ MS analysis. Majority of the patients were males with an average age of 34.54 ± 1.16 years old. Many complained of neurobehavioral changes necessitating consultation at the hospital emergency room. The neurologic and cardiovascular systems were frequently affected. By using the drugs of abuse test kit, methamphetamine was the most common substance of abuse detected and was seen in 40.3% of the samples. Amphetamine type stimulants were the most common group of drugs identified by LC-QTOF/ MS analysis and was seen in 103 instances. New psychoactive substances detected more frequently than others include paramethoxymethamphetamine (PMMA), 3,4- methylenedioxy methamphetamine (MDMA) and 3,4- methylenedioxyamphetamine (MDA). A few cathinones like butylone and cathinone were also detected.

Methamphetamine was the most common substance of abuse detected in urine samples of the participants. New psychoactive substances were also detected in urine samples when LC-QTOF/MS analysis was utilized. Most persons who use drugs are unemployed young- to mid-adult males. The participants often had neurobehavioral and cardiovascular signs and symptoms.

BACKGROUND AND OBJECTIVE

The emergence of antimicrobial resistance (AMR) poses a significant global health threat, with developing countries such as the Philippines facing particularly severe impacts due to resource limitations. The most affected by AMR is Healthcare Acquired Infections (HAIs), including Catheter-Related Bloodstream Infections (CRBSIs). These are commonly associated with biofilm-forming bacteria like Staphylococcus epidermidis, which complicates treatment due to antibiotic resistance. The Philippine variety of Psidium guajava, a folklorically used medicinal plant, has shown potential antimicrobial properties that could offer a new avenue for combating resistant pathogens.

This study evaluated the antibacterial and antibiofilm efficacy of crude Psidium guajava ethanolic leaf extracts (PGELE) against biofilm-forming S. epidermidis (ATCC 12228). PGELE was tested at five concentrations (ranging from 312.5 µg/mL to 10,000 µg/mL) using two-fold serial dilution to determine the Minimum Inhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) using agar dilution count method. For the Minimum Biofilm Inhibitory Concentration (MBIC) and Minimum Biofilm Eradication Concentration (MBEC), crude PGELE was tested at 0.25 x MIC, 0.5 x MIC, MIC, 2 x MIC and 4 x MIC.

The MIC for PGELE against S. epidermidis was determined to be 2500 µg/mL, and the MBC was 5000 µg/mL, indicating that PGELE exhibits bactericidal activity. In biofilm assays, PGELE demonstrated strong antibiofilm activity at concentrations as low as 625 µg/ mL, inhibiting biofilm formation by more than 50%. However, PGELE did not eradicate preformed biofilms, as indicated by the MBEC results at concentrations ranging from 625 µg/mL to 10,000 µg/mL.

Psidium guajava ethanolic leaf extracts exhibit antibacterial and antibiofilm activities against S. epidermidis, particularly in preventing biofilm formation. These findings suggest that PGELE could be developed as an effective natural antimicrobial agent for use in healthcare settings to prevent CRBSIs and other infections caused by biofilm-forming pathogens. Further research and development are warranted to explore the potential of PGELE for antimicrobial drug development.

OBJECTIVES

In response to the need for a simple and fast way of ensuring that generic drugs especially those that contain rifampicin are bioequivalent with reference drugs, this study validated an ultra-high-performance liquid chromatography (UHPLC) method of quantifying rifampicin in human plasma. The study also validated the method's selectivity, linearity, sensitivity, accuracy, precision, and the absence of a carry-over effect adhering to the Philippine Food and Drug Administration guidelines.

Plasma samples were prepared via protein precipitation using methanol containing ascorbic acid. Three microliters (3 uL) of the prepared samples were then analyzed in a Waters Acquity H-Class UPLC® system coupled to a tunable ultraviolet (TUV) detector with an attached UPLC® BEH C-18 column using a developed and optimized method. Briefly, the column temperature was set to 40°C and the sample temperature was set to 10°C. Elution was done using a linear gradient flow of a water-acetonitrile mixture that started with 45% acetonitrile increasing to 60% acetonitrile at 0.5 minutes and back to 45% acetonitrile at 3 minutes and having a constant flow rate of 0.5 mL/min. Detection was done at 340 nm. Method validation was performed following the ICH guidelines for Bioanalytical Method Validation, the same guidelines referenced by the ASEAN Guideline for Harmonisation of Standards and the Philippine Food and Drug Administration (FDA).

The method had an analysis time of 3 minutes wherein rifampicin eluted at 1.4 minutes while the internal standard, rifapentine (IS) eluted at 1.7 minutes. Since no co-eluting endogenous materials were observed for the rifampicin and the internal standard, the method was confirmed to be selective. Its linearity over the range of 2 ug/mL to 25 ug/mL has been validated where it has a limit of detection (LOD) and limit of quantification (LOQ) values of 0.64 ug/mL and 1.94 ug/mL, respectively. The interday and intraday precision, reported as % coefficient of variance (%CV), and interday and intraday accuracy, reported as %error all within the limits of ±20% for the LLOQ and ±15% for the rest indicating its reliability and reproducibility. Lastly, due to the nature of the injection of the sample into the system, wherein a blank immediately follows the highest concentration standard, the method has been cleared of a carry-over effect.

The study successfully validated a UHPLC method of quantifying rifampicin in human plasma. Due to the sample processing method used and the chromatographic conditions set, the method can prepare and analyze samples in a simple yet fast, sensitive, reliable, and reproducible manner. The method can be applied in bioavailability and bioequivalence studies of rifampicin.

Objectives: The Bioavailability/Bioequivalence Unit (BA/BE Unit) of the Department of Pharmacology and Toxicology, College of Medicine, University of the Philippines Manila which has not been operational since 2012, is due for renewal of its accreditation. To date, there are only three Philippine Food and Drug Administration-accredited laboratories that perform bioequivalence studies in the Philippines. One of the prerequisites of registering specific generic medicines is the conduct of Bioequivalence (BE) studies which are performed to ensure that the generic drug is at par with the innovator drug. Thus, this study aimed to determine the feasibility of re-establishing the BA/BE Unit as a bioequivalence testing center. Methods: The feasibility study done is a qualitative descriptive analysis based on expansive literature review and performance of SWOT analysis within the BA/BE unit. Literatures were selected based on its assessed relevance to the study. The databases checked were PubMed and Google Scholar. The terms used were from the Medical Subject Heading (MeSH) including feasibility studies, therapeutic equivalency, and generic drugs. Literature review was performed on the factors affecting the four types of feasibility studies (market, technical, financial, and organizational). A SWOT analysis of the BA/BE Unit was done through the review of records and documents of previous BE studies and focus group discussion among the BA/BE Unit team members. Results: The BA/BE Unit conducted 24 bioequivalence studies from 2006-2009 and still receives inquiries from drug companies. It implements its QMS throughout the pre-analytical, analytical, and post-analytical stages of the workflow. Its organizational structure consists of qualified professionals with updated GCP and GLP certificates. Because of the adequately equipped facility, lower honoraria for government-employed personnel, and lower expenses for laboratories and in-patient admissions, the cost of conducting a bioequivalence study in the BA/BE Unit will be lower than in other BE centers. Conclusion Based on the SWOT analysis and market, technical, financial, and organizational considerations, reestablishing the BA/BE Unit as a bioequivalence testing center is feasible.
Feasibility Studies ; Therapeutic Equivalency ; Drugs, Generic

BACKGROUND AND OBJECTIVE

Oral ivermectin, a broad-spectrum anti-parasitic drug, alone or in combination with permethrin, may be a cheaper and more convenient alternative drug to topical permethrin alone in the treatment of classic scabies. There are no previous studies on the treatment acceptability of the three interventions among individual patients with scabies in the Philippines. The purpose of this study was to understand the experiences and perceptions on treatment acceptability for oral ivermectin, topical permethrin or combination treatment among patients with scabies using the multiple-case study approach.

We conducted a qualitative multiple case study among adult Filipino patients with classic scabies who were prescribed oral ivermectin, topical permethrin or its combination at a government tertiary hospital dermatology outpatient clinic from December 2022 to September 2023. Semi-structured interviews were used as the primary source of data and analyzed together with chart reviews, Dermatology Life Quality Index (DLQI) scores, and clinical images. Interviews were transcribed, coded, and triangulated with other secondary data. A three-person research team employed a reflexive and iterative process of familiarization, coding, and thematic analysis using a modified Theoretical Framework of Acceptability (TFA) to generate case descriptions, within-case analyses, and cross-case syntheses.

The acceptability of scabies treatments (permethrin, ivermectin, and combination therapy) was generally positive. Permethrin, used in three patient cases, was generally perceived as effective but itch relief varied. The burden of whole-body application of permethrin was context-dependent, influenced by living arrangements and family support. Perceived affordability of permethrin was linked to socioeconomic status. Ivermectin, used by one patient case, was perceived as highly effective with no side effects. Its single dose use did not interfere with patient routine. Combination therapy was also considered effective but potential antagonistic effects and the cost of adding permethrin made it less preferred. Reluctance in taking oral pills was noted. All patients valued medical advice and deferred to their physicians for treatment decisions.

All three treatment options were considered effective and safe. Patients generally preferred permethrin over oral ivermectin due to its topical nature and perceived lower side effects. However, affordability and logistical challenges, especially for large households and low-income families, were noted with permethrin. Oral ivermectin elicited hesitation due to its controversial role in COVID-19 and veterinary use. Concerns about added costs and potential antagonism in combination therapy were raised. Despite these considerations, patients ultimately relied on physicians for treatment decisions. This study underscores the importance of understanding patient perspectives, experiences, and the patient-physician relationship in choosing scabies interventions. Addressing patient concerns, providing education, and ensuring ease of use and affordability can enhance treatment acceptability and adherence for better outcomes.

Background and Objective: Oral ivermectin is recommended as an alternative to topical permethrin in Japanese, European, and CDC-STI guidelines for treating classic scabies. The combination of oral ivermectin and topical permethrin is also used in some settings. Partial economic evaluations conducted in India and Egypt have conflicting results, and no cost-effectiveness analysis in the Philippines has compared ivermectin-based regimens to permethrin for scabies treatment. We aimed to determine the cost-effectiveness of oral ivermectin, alone or in combination with permethrin, compared to permethrin, in the treatment of Filipino adult patients with classic scabies. Methods: We used a decision tree model to estimate the cost-effectiveness of two regimens, oral ivermectin alone or in combination with permethrin, compared with permethrin to treat adults and children aged five years and older with classic scabies in the outpatient setting from the household perspective in the Philippines. We estimated total costs and disability-adjusted life years (DALYs) over a one-month follow-up. Input parameters were obtained from secondary data, such as effect estimates for probabilities of clinical outcomes from a network meta-analysis, DALYs from the Global Burden of Disease 2019, and prevailing market cost in the Philippines (DPRI 2022 with recommended markup by DOH, and leading drugstores) as of August 2022. We computed for incremental cost-effectiveness ratio (ICER) and net monetary benefit (NMB) to determine which of the interventions are cost-effective. Univariate and probabilistic sensitivity analyses, and scenario analyses were conducted to assess the impact of parameter and structural uncertainty. Results: Ivermectin-based regimens are suggested to be likely cost-saving compared to permethrin in the Philippine outpatient setting. Base case analysis showed that oral ivermectin had higher cost-savings (change in cost, -1,039.31; change in DALYS, 0.00027), while combination oral ivermectin/permethrin had higher DALYs averted (change in cost, PhP -1,019.78; change in DALYs, 0.00045), compared to permethrin. Combination oral ivermectin/permethrin (56%) was the most cost-effective, followed by oral ivermectin (44%) compared to permethrin (0%) through probabilistic sensitivity analysis. Estimates for ivermectin were sensitive to risk of cure for ivermectin vs permethrin using 1-way deterministic sensitivity analysis. Oral ivermectin was favored over combination oral ivermectin/permethrin at all thresholds based on the cost-effectiveness acceptability curve. Conclusion Both ivermectin-based regimens seem to be cost-saving compared to permethrin in the treatment of classic scabies in the Philippine outpatient setting. Clinicians may consider oral ivermectin, alone or in combination with permethrin as an alternative first-line or second-line treatment depending on patient preference, adverse event risk profile, availability, and economic capacity. This needs to be confirmed using primary data from Filipino patients to enhance the robustness of the findings and support evidence-based local decision-making in different settings. Less uncertainty in modelled parameters can give greater confidence in the results, which can be adopted for budget impact analysis and allow more rational resource allocation. Value of information analysis can be done to determine whether the expense of future RCTs or surveys in Filipinos to collect primary data is worth it. The cost of reducing uncertainty, if deemed worth the cost of further studies, may facilitate population-level decision-making and budget planning. Findings may further inform practice guideline development, coverage decisions, and national control program planning by providing the most cost-effective scabies intervention.
Scabies ; Ivermectin ; Permethrin ; Cost-Benefit Analysis

Background and Objective: Staphylococcus aureus is the leading cause of skin and soft tissue infections such as abscesses, furuncles, and cellulitis. Biofilm forming strains of S. aureus have higher incidence of antimicrobial resistance to at least three or more antibiotics and are considered as multidrug resistant. Since S. aureus biofilm-producing strains have higher rates of multidrug and methicillin resistance compared to non-biofilm-producing strains, the need for alternative therapeutic option is important. Furthermore, rates of methicillin-resistant Staphylococcus aureus (MRSA) in Asia remain high. Results of the study may provide support for the clinical uses of P. betle as a topical antibacterial and antiseptic in the treatment and prevention of infections involving the skin, mouth, throat, and indwelling medical devices. Thus, this study aimed to evaluate the in vitro antibacterial and antibiofilm activities of Piper betle L. ethanolic leaf extract (PBE) against a biofilm-forming methicillin-sensitive Staphylococcus aureus ATCC 29213 (MSSA). Methods: The minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of PBE against MSSA were determined using the agar dilution assay. The biofilm inhibition and eradication assays using crystal violet were done to quantify the antibiofilm activities of PBE on MSSA biofilm. Results: PBE showed activity against MSSA in agar dilution assay with MIC and MBC values of 2500 μg/mL and 5000 μg/mL, respectively. At subinhibitory concentrations, PBE showed biofilm inhibition activity at 1250 μg/mL but a lower percent eradication of biofilms as compared to oxacillin was noted. Conclusion PBE showed antibacterial activities including biofilm inhibition against methicillin-sensitive Staphylococcus aureus ATCC 29213 (MSSA).
Piper betle ; Staphylococcus aureus ; Anti-Bacterial Agents ; Biofilms