REFERENCE FORMULA
Reference formula
Reference basis: 1000 mL
| Ingredient | Source quantity | Scaled quantity |
|---|---|---|
| Benzoic acid | 50 g | — |
| Propylene glycol | 750 mL | — |
| Freshly boiled and cooled purified water | q.s. ad 1000 mL | — |
REFERENCE FORMULA SCALING
Proportional quantities of the same formula
Arithmetic aid. It does not change strength, dose, method or BUD and does not authorise compounding.
Theoretical calculation sheet
CGR-BP-048 · Benzoic Acid Solution
Not an approved master record or batch release. BUD is not calculated.
| Ingredient | Reference | Calculated | Lot | Actual quantity |
|---|
Prerequisite formulations
No separate prerequisite monograph is listed.
Documentation
Preparation description
Liquid base or auxiliary solution: Benzoic Acid Solution. Additional appearance criteria are not established by the specific text reviewed. [1]
Action and use
Pharmaceutical base or excipient for incorporation into an appropriate preparation. Compatibility with each active requires separate assessment. [1]
Specifications
Benzoic acid 4.75–5.25% w/v; mass/mL 1.045–1.055 g. [1]
Light
Finished-product photostability is not specified. Any required container light protection is stated under Storage. [1]
Air and oxidation
No oxidative stability study of the finished mixture or inert-atmosphere requirement is provided. Use the source container. [1]
Water and solubility
Humidity
Temperature
No permitted temperature excursion or freeze–thaw cycle is established. Processing and storage temperatures are stated in their respective fields. [1]
pH and compatibility
Benzoic acid/benzoate preservation is described by EMA in acidic conditions, pH 2.5–4.5. Preservation at higher pH must not be assumed. [4]
Other interactions
No complete compatibility test with added actives or alternative excipients is provided. Substitutions require separate evidence. [1]
Ingredient-specific information
Propylene glycol (1,2-propanediol): colourless viscous water-miscible cosolvent and humectant. A small amount does not establish adequate preservation.
Propylene Glycol: raw-material water solubility is classified as miscible by JP.
Benzoic Acid: raw-material water solubility is classified as slightly soluble by JP.
Propylene glycol: retain original manufacturer, lot and reliable certificate. For the applicable raw materials, FDA describes DEG and EG testing, each limited to 0.10% under the relevant monograph. This is a raw-material limit. [3], [5], [6], [7]
Propylene Glycol: raw-material water solubility is classified as miscible by JP.
Benzoic Acid: raw-material water solubility is classified as slightly soluble by JP.
Propylene glycol: retain original manufacturer, lot and reliable certificate. For the applicable raw materials, FDA describes DEG and EG testing, each limited to 0.10% under the relevant monograph. This is a raw-material limit. [3], [5], [6], [7]
Staff protection
Risk assessment
Propylene glycol: assess exposure from all medicines, especially in neonates, children under 5 and renal/hepatic impairment. For oral dosing: mg/kg/day = mg/mL × daily mL ÷ body weight in kg.
Benzoic acid/benzoates may worsen neonatal jaundice through bilirubin displacement. Assess use in neonates up to 4 weeks; topical exposure can also irritate.
Reference batch: 1000 mL. First ingredient: Benzoic acid, 50 g. Independently check chemical form, units and every scale conversion before weighing.
As an intermediate, label identity and strength clearly and do not dispense as a finished medicine. Dilution or addition of an active requires new excipient, preservation and BUD calculations. Confirm release of every required base.
For the local assessment record quantity per preparation, work frequency, duration of open handling, potential exposure routes and effectiveness of controls. These are assessment inputs; no fictitious final risk score is assigned.
Release checkpoint: confirm final volume or mass at the reference temperature, intended clarity or dispersion, and specified container/closure. Do not equate grams and millilitres without a justified density. [1], [3], [4], [11], [13]
Benzoic acid/benzoates may worsen neonatal jaundice through bilirubin displacement. Assess use in neonates up to 4 weeks; topical exposure can also irritate.
Reference batch: 1000 mL. First ingredient: Benzoic acid, 50 g. Independently check chemical form, units and every scale conversion before weighing.
As an intermediate, label identity and strength clearly and do not dispense as a finished medicine. Dilution or addition of an active requires new excipient, preservation and BUD calculations. Confirm release of every required base.
For the local assessment record quantity per preparation, work frequency, duration of open handling, potential exposure routes and effectiveness of controls. These are assessment inputs; no fictitious final risk score is assigned.
Release checkpoint: confirm final volume or mass at the reference temperature, intended clarity or dispersion, and specified container/closure. Do not equate grams and millilitres without a justified density. [1], [3], [4], [11], [13]
Compounding conditions
BUD rationale
No specific experimental period was located covering the complete exact formulation, container and microbiological suitability.
Contains 750 mL propylene glycol, water to 1000 mL and 50 g benzoic acid. Do not assign final aw from another polyol’s table without mixture evidence. Select a conservative aqueous limit only if benzoic-acid crystallisation at 2–8 °C is excluded.
Selected conservative general rule: up to 14 days at 2–8 °C for an aqueous form without adequately established preservation. Refrigeration must not cause precipitation, irreversible separation or other loss of suitability. If that condition fails, do not apply 14 days at room temperature; obtain specific short-use evidence.
Use-by date = the earliest allowed date from preparation plus selected period, ingredient expiries and any shorter supported limit. In-use dating never extends overall BUD. Complete the actual date for the batch after the required checks.
A default is a conservative dating limit, not experimental proof of batch stability. Its category depends on final composition, preservation and permitted temperatures. Water percentage or loss on drying does not determine aw. Document using SOP-014/F-006; use SOP-017/F-012 for specific aw evidence.
USP clarification: aw measurement is not required for every nonsterile preparation. Category assignment may use the exact composition and relevant representative examples; an uncertain or borderline formulation is best assessed by a suitable specific measurement. This edition contains no measured aw or released batch. The final preparation generally must not outlast the remaining BUD of its compounded bases/intermediates. An exception requires specific justification that physical, chemical and microbiological quality is not adversely affected. Record the final limit, intermediate preparation dates and their actual expiry dates separately. [1], [10], [12], [14]
Contains 750 mL propylene glycol, water to 1000 mL and 50 g benzoic acid. Do not assign final aw from another polyol’s table without mixture evidence. Select a conservative aqueous limit only if benzoic-acid crystallisation at 2–8 °C is excluded.
Selected conservative general rule: up to 14 days at 2–8 °C for an aqueous form without adequately established preservation. Refrigeration must not cause precipitation, irreversible separation or other loss of suitability. If that condition fails, do not apply 14 days at room temperature; obtain specific short-use evidence.
Use-by date = the earliest allowed date from preparation plus selected period, ingredient expiries and any shorter supported limit. In-use dating never extends overall BUD. Complete the actual date for the batch after the required checks.
A default is a conservative dating limit, not experimental proof of batch stability. Its category depends on final composition, preservation and permitted temperatures. Water percentage or loss on drying does not determine aw. Document using SOP-014/F-006; use SOP-017/F-012 for specific aw evidence.
USP clarification: aw measurement is not required for every nonsterile preparation. Category assignment may use the exact composition and relevant representative examples; an uncertain or borderline formulation is best assessed by a suitable specific measurement. This edition contains no measured aw or released batch. The final preparation generally must not outlast the remaining BUD of its compounded bases/intermediates. An exception requires specific justification that physical, chemical and microbiological quality is not adversely affected. Record the final limit, intermediate preparation dates and their actual expiry dates separately. [1], [10], [12], [14]
Prerequisites
No separately registered base is required. Any commercial vehicle remains the exact named product in the formula table. [1]
Equipment
Balance with suitable minimum weight, mortar/pestle or homogeniser, mixing vessels, spatulas, thermometer for heated processes and volumetric equipment for mL quantities. [1]
Compounding method
Dissolve benzoic acid in propylene glycol; add water in portions with continuous stirring to final volume. [1]
Observations
The final quantity is the master-formula basis. Record actual yield, losses and deviations in the batch record. [1]
Container and packaging
Selection for local assessment: well-closed bottle compatible with the liquid. Check cleanliness, integrity, closure and material compatibility before filling. The specific monograph does not validate a particular commercial container. [1]
Quality control
Add 20 mL previously neutralised 96% ethanol to 10 mL sample and titrate with 0.1 M NaOH/phenolphthalein R1. Each mL equals 12.21 mg benzoic acid.
Polyol incoming QC: pharmacies test each lot or ensure documented testing by a reliable supplier, as described by FDA. IR identity alone does not exclude DEG/EG.
Record the method, acceptance criterion, actual result and reviewer separately in F-005. A critical specification failure requires quarantine and investigation under SOP-015; retesting needs justification. [1], [7], [13]
Polyol incoming QC: pharmacies test each lot or ensure documented testing by a reliable supplier, as described by FDA. IR identity alone does not exclude DEG/EG.
Record the method, acceptance criterion, actual result and reviewer separately in F-005. A critical specification failure requires quarantine and investigation under SOP-015; retesting needs justification. [1], [7], [13]
Storage
Dispensing
Intermediate base for compounding. Adding an active requires reassessment of the final composition, pH, preservation and BUD. [1]
Labelling
v9_controls
The numeric value is a literature reference ceiling subject to its specific conditions. No actual batch BUD has been assigned and no aw measurements have been produced. The exact formula, prerequisites, container, storage and quality evidence require approval for the actual application. The BUD clock starts when compounding begins. Use the shortest applicable supported limit and assess in-use dating separately. USP categories are a technical framework and are not presented as Greek legislation.
Independent Greek/English adaptation and organisation of facts from the cited source. This is not an official translation or publisher endorsement.
Sources and references
- British Pharmacopoeia 2016 — Benzoic Acid Solution2016PDF pp. 1; user-supplied BP extract; URL is publisher catalogue, not the licensed full monographmaster formula2026-09-10
- PN/L/PG/002/00 INDUMENTARIAΔιαθέσιμο κείμενο / Retrieved textPDF pp. 1–5general staff protection2026-09-10
- EMA — Questions and answers on propylene glycol used as an excipient, EMA/CHMP/704195/20139 October 2017Sections 1–3 and annexingredient facts2026-09-12
- EMA — Questions and answers on benzoic acid and benzoates, EMA/CHMP/508189/20139 October 2017Preservative pH and neonatal safetyingredient facts2026-09-12
- MHLW — Japanese Pharmacopoeia XVIII: Propylene GlycolJP XVIII, 2021; English textPrinted p. 1600; Description; Containers and storageraw-material monograph2026-09-12
- MHLW — Japanese Pharmacopoeia XVIII: Benzoic AcidJP XVIII, 2021; English textPrinted p. 523; Description; Containers and storageraw-material monograph2026-09-12
- FDA — Testing of Glycerin, Propylene Glycol, Maltitol Solution, Hydrogenated Starch Hydrolysate, Sorbitol Solution, and Other High-Risk Drug Components for Diethylene Glycol and Ethylene GlycolMay 2023, revision 1Recommendations; section on pharmacy compoundingraw material quality2026-09-12
- ASHP — USP <795> Key Changes2023pp. 1–3: scope, water activity and staff precautionsprofessional guidance; not the licensed USP chapter2026-09-12
- Texas State Board of Pharmacy — adopted 22 TAC §291.131, nonsterile compoundingTexas Register, 7 June 2024Beyond-use dating: aw categories, 14/35/90/180 days, limits and extensionspublic regulatory implementation of USP <795> BUD framework; not Greek law2026-09-12
- Illinois IDFPR — Nonsterile Compounding Self-Inspection ReportPublic checklist, retrieved 12 September 2026pp. 15–16, Establishing beyond-use datesPublic regulatory implementation of USP <795>; not Greek law; general limits and requirements for extension2026-09-12
- NIOSH — Managing Hazardous Drug Exposures: Information for Healthcare Settings2023; DHHS (NIOSH) 2023-130Risk assessment; printed pp. 27–33, activity/formulation control tableWorkplace exposure, hierarchy of controls and activity-specific PPE; US government public-domain document2026-09-12
- USP — Compounding Standards and Beyond-Use Dates, 2022 updateNovember 2022, published by USP; public copy hosted by Mississippi Boardpp. 1–2; nonsterile tableRisk-based default categories; not product-specific stability or Greek law2026-09-12
- PIC/S — Guide to Good Practices for the Preparation of Medicinal Products in Healthcare EstablishmentsPE 010-4, 1 March 2014Chapters 1–9; Annex 2 (nonsterile liquids, creams, ointments)Professional quality-system framework; not automatic national legal adoption or certification2026-09-12
- USP — General Chapter <795> FAQsUpdated 1 November 2023Questions 52, 54–56, 60–62; PDF pp. 11–14Primary clarification of aw classification, extension prerequisites and compounded-component BUDs; not automatic Greek legal adoption2026-10-14