REFERENCE FORMULA
Reference formula
Reference basis: 100 g
| Ingredient | Source quantity | Scaled quantity |
|---|---|---|
| Methylparaben | 8 g | — |
| Propylparaben | 2 g | — |
| Propylene glycol | q.s. ad 100 g | — |
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-ES-017 · Hydroxybenzoate Concentrate EX025
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
Clear, colourless solution. [1]
Action and use
Compounding base or auxiliary vehicle as named; addition of an active requires separate compatibility/stability assessment. [1]
Specifications
Clear, colourless solution. [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
Propylene Glycol: JP classifies the corresponding pure raw material as miscible in water.
Methyl Parahydroxybenzoate: JP classifies the corresponding pure raw material as slightly soluble in water.
Propyl Parahydroxybenzoate: JP classifies the corresponding pure raw material as very slightly soluble in water. [6], [7], [8]
Methyl Parahydroxybenzoate: JP classifies the corresponding pure raw material as slightly soluble in water.
Propyl Parahydroxybenzoate: JP classifies the corresponding pure raw material as very slightly soluble in water. [6], [7], [8]
Humidity
Temperature
For the finished product the source specifies:
Amber bottle; <30 °C, protected from moisture. [1]
Amber bottle; <30 °C, protected from moisture. [1]
pH and compatibility
No finished-product pH range is specified. Do not add a pH adjuster without a supported formula change. [1]
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.
Methyl Parahydroxybenzoate: raw-material water solubility is classified as slightly soluble by JP.
Propyl Parahydroxybenzoate: raw-material water solubility is classified as very 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. [5], [6], [7], [8], [9]
Propylene Glycol: raw-material water solubility is classified as miscible by JP.
Methyl Parahydroxybenzoate: raw-material water solubility is classified as slightly soluble by JP.
Propyl Parahydroxybenzoate: raw-material water solubility is classified as very 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. [5], [6], [7], [8], [9]
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.
Reference batch: 100 g. First ingredient: Methylparaben, 8 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.
For this procedure’s heating stage, check thermometer, heating method, duration and prevention of overheating/solvent loss. Completion of mixing does not establish cooling or complete homogenisation.
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], [5], [13], [15]
Reference batch: 100 g. First ingredient: Methylparaben, 8 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.
For this procedure’s heating stage, check thermometer, heating method, duration and prevention of overheating/solvent loss. Completion of mixing does not establish cooling or complete homogenisation.
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], [5], [13], [15]
Compounding conditions
The corresponding AEMPS SOP specifies room temperature 25 ± 5°C and relative humidity ≤60%, unless the particular formula requires otherwise. This is the work environment, not processing or storage temperature.
Follow the addition sequence, temperatures and times stated under Preparation Procedure. The specific monograph is not a complete qualification of the local facility/equipment. [1], [3]
Follow the addition sequence, temperatures and times stated under Preparation Procedure. The specific monograph is not a complete qualification of the local facility/equipment. [1], [3]
BUD rationale
Period reported by source: 6 months.
This duration is a specific formulary/source instruction. This review did not verify a complete primary study establishing chemical, physical and microbiological extension for the same finished formulation.
Selected general rule: up to 180 days at 20–25 °C for a solid or nonaqueous nonoral-liquid form with supported aw <0.6. Initial quality/moisture, exclusion of water ingress and physical suitability must support this category.
The reference-policy ceiling in this edition is the shorter of the source period above and the general ceiling. Extension needs matching active/excipients/strength, container, temperature, a stability-indicating method and the required microbiological evidence for aqueous extension. An applicable official USP–NF compounded monograph is assessed separately in its complete text.
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 does not require water-activity measurement for every nonsterile preparation. A justified classification of the actual formulation may guide dating; record it explicitly as inferred, not measured. Uncertain or borderline classification requires specific evidence or a suitable measurement. Finished-product dating does not outlast the available dating of previously compounded components/bases unless adequate specific evidence for the exact finished preparation has been formally adopted. [1], [11], [12], [14], [16]
This duration is a specific formulary/source instruction. This review did not verify a complete primary study establishing chemical, physical and microbiological extension for the same finished formulation.
Selected general rule: up to 180 days at 20–25 °C for a solid or nonaqueous nonoral-liquid form with supported aw <0.6. Initial quality/moisture, exclusion of water ingress and physical suitability must support this category.
The reference-policy ceiling in this edition is the shorter of the source period above and the general ceiling. Extension needs matching active/excipients/strength, container, temperature, a stability-indicating method and the required microbiological evidence for aqueous extension. An applicable official USP–NF compounded monograph is assessed separately in its complete text.
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 does not require water-activity measurement for every nonsterile preparation. A justified classification of the actual formulation may guide dating; record it explicitly as inferred, not measured. Uncertain or borderline classification requires specific evidence or a suitable measurement. Finished-product dating does not outlast the available dating of previously compounded components/bases unless adequate specific evidence for the exact finished preparation has been formally adopted. [1], [11], [12], [14], [16]
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 both parabens in propylene glycol using a water bath at about 50 °C. [1]
Observations
Concentrate for dilution; contains propylene glycol. [1]
Container and packaging
Amber bottle; <30 °C, protected from moisture. [1]
Quality control
Clear, colourless solution.
Additional tests from the referenced SOP:
Appearance and mass/volume. For batches: colour, clarity/opalescence, relative density, pH and microbiological testing RFE 5.1.4.
pH under PN/CP/001: normally test the untreated sample unless otherwise specified. Accurate measurement follows potentiometric RFE 2.2.3; strips are limited to checks not requiring high accuracy.
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], [3], [4], [9], [15]
Additional tests from the referenced SOP:
Appearance and mass/volume. For batches: colour, clarity/opalescence, relative density, pH and microbiological testing RFE 5.1.4.
pH under PN/CP/001: normally test the untreated sample unless otherwise specified. Accurate measurement follows potentiometric RFE 2.2.3; strips are limited to checks not requiring high accuracy.
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], [3], [4], [9], [15]
Storage
Amber bottle; <30 °C, protected from moisture. [1]
Dispensing
Intermediate base for compounding. Adding an active requires reassessment of the final composition, pH, preservation and BUD. [1]
Labelling
Hydroxybenzoate Concentrate EX025
Compounding base — not for direct administration
Quantity: ____ Batch: ____
Prepared: ____ Use by: ____
Patient / dose / frequency: ____
Storage: Amber bottle; <30 °C, protected from moisture.
Temperature for this batch BUD: ____ [1]
Compounding base — not for direct administration
Quantity: ____ Batch: ____
Prepared: ____ Use by: ____
Patient / dose / frequency: ____
Storage: Amber bottle; <30 °C, protected from moisture.
Temperature for this batch BUD: ____ [1]
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
- FN/2003/EX/025 SOLUCIÓN CONCENTRADA DE HIDROXIBENZOATOS2003PDF pp. 2master formula2026-09-10
- PN/L/PG/002/00 INDUMENTARIAΔιαθέσιμο κείμενο / Retrieved textPDF pp. 1–5general staff protection2026-09-10
- PN/L/FF/007/00 ELABORACIÓN DE SOLUCIONESΔιαθέσιμο κείμενο / Retrieved textPDF pp. 1–6preparation sop2026-09-10
- PN/L/CP/001/00 DETERMINACIÓN DE PHΔιαθέσιμο κείμενο / Retrieved textPDF pp. 1–5qc method2026-09-10
- EMA — Questions and answers on propylene glycol used as an excipient, EMA/CHMP/704195/20139 October 2017Sections 1–3 and annexingredient facts2026-09-12
- MHLW — Japanese Pharmacopoeia XVIII: Propylene GlycolJP XVIII, 2021; English textPrinted p. 1600; Description; Containers and storageraw-material monograph2026-09-12
- MHLW — Japanese Pharmacopoeia XVIII: Methyl ParahydroxybenzoateJP XVIII, 2021; English textPrinted p. 1343; Description; Containers and storageraw-material monograph2026-09-12
- MHLW — Japanese Pharmacopoeia XVIII: Propyl ParahydroxybenzoateJP XVIII, 2021; English textPrinted p. 1601; 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> FAQs (official, updated 1 November 2023)Updated 1 November 2023; retrieved 14 October 2026Q52, Q61–64; use with the applicable full chapterWater-activity classification, component dating and BUD documentation; general professional framework, not a Greek legal adoption or formula-specific study2026-10-14